Android学习笔记总结
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搭建 Android 的开发环境，以及写一个简单的示例程序
· 在 Windows 下搭建 Android 开发环境
· Android 项目的目录结构说明
· 写一个简单的 Hello World 程序
一、在 Windows 下搭建 Android 开发环境
1、安装 JDK (Java Development Kit)
http://download.java.net/jdk6/
2、安装 Android SDK
http://developer.android.com/sdk
3、安装 Eclipse
http://www.eclipse.org/
4、打开 Eclipse ，并安装其 Android 插件（ADT）
打开菜单 "Help" -> "Install New Software"，在 "Availabe Software" 中加入地址 http://dl-ssl.google.com/android/eclipse/ ，然后安装 ADT(Android Development Tools)
5、新建 Android 项目
"New" -> Android Project，Project Name - 项目名称；Build Target - 编译项目的 SDK 版本；Application name - 程序名称；Package name - 包名；Min SDK Version - 程序所支持的最低 SDK 版本代号（2 对应 1.1，3 对应 1.5，4 对应 1.6）
6、运行 Android 项目
打开菜单 "Run" -> "Run Configurations" -> New launch configuration，设置启动项目名称，在 Android 选项卡中选择启动项目，在 Target 选项卡中设置模拟器
7、创建/使用模拟 SD 卡
创建 SD 卡，运行类似如下命令：mksdcard -l sdcard 512M d:\android\sdcard.img
模拟器中使用 SD 卡，在项目配置的 Target 选项卡的 "Additional Emulator Command Line Options" 框中输入类似如下参数：-sdcard d:\android\sdcard.img
8、配置模拟器
运行类似如下命令：android create avd --name android15 --target 2。或者直接在菜单 "Window" -> "Android AVD Manager" 中配置模拟器
9、浏览模拟 SD 卡中的内容
调试程序，在 DDMS 中选择 "File Explorer" ，在其中的 sdcard 目录下就是模拟 SD 卡中的内容
10、查看日志 LogCat
Window -> Show View -> Other -> Android -> LogCat
11、在模拟器中安装/卸载 apk
安装 apk 运行类似如下命令：adb install name.apk；卸载 apk 运行类似如下命令：adb uninstall packagename（注：这里的参数是需要卸载的包名）
12、反编译 Android 程序
解压 apk 文件，取出其中的 classes.dex 文件，运行类似如下命令：dexdump.exe -d classes.dex > dump.txt（其意思是将 classes.dex dump 出来，并将反编译后的代码保存到指定的文本文件中）
13、人品不好是出现的某些错误的解决办法
如果出现类似如下的错误等
no classfiles specified
Conversion to Dalvik format failed with error 1
解决办法：Project -> Clean
出现 Android SDK Content Loader 60% （一直卡在 60%）
解决办法：Project -> 去掉 Build Automatically 前面的勾
14、查看 SDK 源代码
先想办法搞到源代码，如这个地址 http://www.digginmobile.com/android.asp ，然后将其解压到 SDK 根路径下的 sources 文件夹内即可
二、Android 项目的目录结构
1、src - 用于放置源程序
2、gen - 自动生成 R.java 文件，用于引用资源文件（即 res 目录下的数据）
3、assets - 用于放置原始文件，Android 不会对此目录下的文件做任何处理，这是其与 res 目录不同的地方
4、res/drawable - 用于放置图片之类的资源；res/layout - 用于放置布局用的 xml 文件；res/values - 用于放置一些常量数据
5、AndroidManifest.xml - Android 程序的清单文件，相当于配置文件，配置应用程序名称、图标、Activity、Service、Receiver等
三、Hello World 程序
1、res/layout/main.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<!--
设置 ID 的方式：ID前加前缀，@+id/
引用资源文件内字符串资源的方式：指定的资源名称前加前缀，@string/
-->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/layout"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/txt"
/>
</LinearLayout>
2、res/values/strings.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">layout 直接调用 values 中的字符串</string>
<string name="hello2">编程方式调用 values 中的字符串</string>
<string name="app_name">webabcd_hello</string>
</resources>
3、res/drawable 目录下放置一个名为 icon.png 的图片文件
4、AndroidManifest.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.webabcd.hello"
android:versionCode="1"
android:versionName="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".Main"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<uses-sdk android:minSdkVersion="3" />
</manifest>
5、Main.java
代码
package com.webabcd.hello;
import android.app.Activity;
import android.os.Bundle;
import android.widget.LinearLayout;
import android.widget.TextView;
public class Main extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// 将指定的布局文件作为 Activity 所显示的内容
setContentView(R.layout.main);
// 动态地在指定的容器控件上添加新的控件
TextView txt = new TextView(this);
txt.setText("动态添加控件");
// setContentView(txt);
((LinearLayout)this.findViewById(R.id.layout)).addView(txt);
// 引用资源文件内的内容作为输出内容
TextView txt1 = (TextView)this.findViewById(R.id.txt);
txt1.setText(this.getString(R.string.hello2));
}
}
Android(2) - 布局(Layout)和菜单(Menu)
介绍
在 Android 中各种布局的应用，以及菜单效果的实现
· 各种布局方式的应用，FrameLayout, LinearLayout, TableLayout, AbsoluteLayout, RelativeLayout
· 为指定元素配置上下文菜单，为应用程序配置选项菜单，以及多级菜单的实现
1、各种布局方式的演示
res/layout/main.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<!--
layout_width - 宽。fill_parent: 宽度跟着父元素走；wrap_content: 宽度跟着本身的内容走；直接指定一个 px 值来设置宽
layout_height - 高。fill_parent: 高度跟着父元素走；wrap_content: 高度跟着本身的内容走；直接指定一个 px 值来设置高
-->
<!--
LinearLayout - 线形布局。
orientation - 容器内元素的排列方式。vertical: 子元素们垂直排列；horizontal: 子元素们水平排列
gravity - 内容的排列形式。常用的有 top, bottom, left, right, center 等，详见文档
-->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:gravity="right"
android:layout_width="fill_parent" android:layout_height="fill_parent">
<!--
FrameLayout - 层叠式布局。以左上角为起点，将 FrameLayout 内的元素一层覆盖一层地显示
-->
<FrameLayout android:layout_height="wrap_content"
android:layout_width="fill_parent">
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="FrameLayout">
</TextView>
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="Frame Layout">
</TextView>
</FrameLayout>
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="@string/hello" />
<!--
TableLayout - 表格式布局。
TableRow - 表格内的行，行内每一个元素算作一列
collapseColumns - 设置 TableLayout 内的 TableRow 中需要隐藏的列的列索引，多个用“,”隔开
stretchColumns - 设置 TableLayout 内的 TableRow 中需要拉伸（该列会拉伸到所有可用空间）的列的列索引，多个用“,”隔开
shrinkColumns - 设置 TableLayout 内的 TableRow 中需要收缩（为了使其他列不会被挤到屏幕外，此列会自动收缩）的列的列索引，多个用“,”隔开
-->
<TableLayout android:id="@+id/TableLayout01"
android:layout_width="fill_parent" android:layout_height="wrap_content"
android:collapseColumns="1">
<TableRow android:id="@+id/TableRow01" android:layout_width="fill_parent"
android:layout_height="wrap_content">
<TextView android:layout_width="wrap_content"
android:layout_weight="1" android:layout_height="wrap_content"
android:text="行1列1" />
<TextView android:layout_width="wrap_content"
android:layout_weight="1" android:layout_height="wrap_content"
android:text="行1列2" />
<TextView android:layout_width="wrap_content"
android:layout_weight="1" android:layout_height="wrap_content"
android:text="行1列3" />
</TableRow>
<TableRow android:id="@+id/TableRow01" android:layout_width="wrap_content"
android:layout_height="wrap_content">
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="行2列1" />
</TableRow>
</TableLayout>
<!--
AbsoluteLayout - 绝对定位布局。
layout_x - x 坐标。以左上角为顶点
layout_y - y 坐标。以左上角为顶点
-->
<AbsoluteLayout android:layout_height="wrap_content"
android:layout_width="fill_parent">
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="AbsoluteLayout"
android:layout_x="100px"
android:layout_y="100px" />
</AbsoluteLayout>
<!--
RelativeLayout - 相对定位布局。
layout_centerInParent - 将当前元素放置到其容器内的水平方向和垂直方向的中央位置（类似的属性有 ：layout_centerHorizontal, layout_alignParentLeft 等）
layout_marginLeft - 设置当前元素相对于其容器的左侧边缘的距离
layout_below - 放置当前元素到指定的元素的下面
layout_alignRight - 当前元素与指定的元素右对齐
-->
<RelativeLayout android:id="@+id/RelativeLayout01"
android:layout_width="fill_parent" android:layout_height="fill_parent">
<TextView android:layout_width="wrap_content" android:id="@+id/abc"
android:layout_height="wrap_content" android:text="centerInParent=true"
android:layout_centerInParent="true" />
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="marginLeft=20px"
android:layout_marginLeft="20px" />
<TextView android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="xxx"
android:layout_below="@id/abc" android:layout_alignRight="@id/abc" />
</RelativeLayout>
</LinearLayout>
res/values/strings.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hello Layout</string>
<string name="app_name">webabcd_layout</string>
</resources>
Main.java
代码
package com.webabcd.layout;
import android.app.Activity;
import android.os.Bundle;
public class Main extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}
2、上下文菜单，选项菜单，子菜单
res/layout/main.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:id="@+id/txt1" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="@string/hello_contextMenu" />
<TextView android:id="@+id/txt2" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="@string/hello_subMenu" />
</LinearLayout>
res/values/strings.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello_contextMenu">Hello Context Menu</string>
<string name="hello_subMenu">Hello Context Sub Menu</string>
<string name="app_name">webabcd_menu</string>
</resources>
Main.java
代码
package com.webabcd.menu;
import android.app.Activity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuItem;
import android.view.SubMenu;
import android.view.View;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.TextView;
import android.widget.Toast;
// 演示两种菜单的实现方式：上下文菜单（通过在某元素上长按，来呼出菜单）和选项菜单（通过按手机上的菜单按钮，来呼出菜单）
public class Main extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 为 R.id.txt1 注册一个上下文菜单（在此 TextView 上长按，则会呼出上下文菜单）
// 具体呼出的菜单内容需要重写 onCreateContextMenu 来创建
TextView txt1 = (TextView) this.findViewById(R.id.txt1);
this.registerForContextMenu(txt1);
// 为 R.id.txt2 注册一个上下文菜单
TextView txt2 = (TextView) this.findViewById(R.id.txt2);
this.registerForContextMenu(txt2);
}
// 重写 onCreateContextMenu 用以创建上下文菜单
// 重写 onContextItemSelected 用以响应上下文菜单
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
// 创建 R.id.txt1 的上下文菜单
if (v == (TextView) this.findViewById(R.id.txt1)) {
// ContextMenu.setIcon() - 设置菜单的图标
// ContextMenu.setHeaderTitle() - 设置菜单的标题
menu.setHeaderIcon(R.drawable.icon01);
menu.setHeaderTitle("我是菜单");
// 用 ContextMenu.add() 来增加菜单项，返回值为 MenuItem
// 第一个参数：组ID
// 第二个参数：菜单项ID
// 第三个参数：顺序号
// 第四个参数：菜单项上显示的内容
menu.add(1, 0, 0, "菜单1");
// MenuItem - 新增菜单项后的返回类型，针对菜单项的其他设置在此对象上操作
menu.add(1, 1, 1, "菜单2").setCheckable(true);
}
// 创建 R.id.txt2 的上下文菜单（多级上下文菜单）
else if (v == (TextView) this.findViewById(R.id.txt2)) {
// ContextMenu.addSubMenu("菜单名称") - 用来添加子菜单。子菜单其实就是一个特殊的菜单
SubMenu sub = menu.addSubMenu("父菜单1");
sub.setIcon(R.drawable.icon01);
sub.add(0, 0, 0, "菜单1");
sub.add(0, 1, 1, "菜单2");
sub.setGroupCheckable(1, true, true);
SubMenu sub2 = menu.addSubMenu("父菜单2");
sub2.setIcon(R.drawable.icon01);
sub2.add(1, 0, 0, "菜单3");
sub2.add(1, 1, 1, "菜单4");
sub2.setGroupCheckable(1, true, false);
}
}
// 重写 onCreateOptionsMenu 用以创建选项菜单
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuItem menuItem = menu.add(0, 0, 0, "菜单111111111111111111111");
// MenuItem.setIcon() - 设置菜单项的图标
// MenuItem.setTitleCondensed() - 菜单的简标题，如果指定了简标题的话，菜单项上的标题将会以此简标题为准
// MenuItem.setAlphabeticShortcut() - 设置选中此菜单项的快捷键
// 注：菜单项超过 6 个的话，第 6 个菜单将会变为 More 菜单，多余的菜单会在单击 More 菜单之后显示出来
menuItem.setIcon(R.drawable.icon01);
menuItem.setTitleCondensed("菜单1");
menuItem.setAlphabeticShortcut('a');
menu.add(0, 1, 1, "菜单2").setIcon(R.drawable.icon02);
menu.add(0, 2, 2, "菜单3").setIcon(R.drawable.icon03);
menu.add(0, 3, 3, "菜单4");
menu.add(0, 4, 4, "菜单5");
menu.add(0, 5, 5, "菜单6");
menu.add(0, 6, 6, "菜单7").setIcon(R.drawable.icon04);
menu.add(0, 7, 7, "菜单8").setIcon(R.drawable.icon05);
return true;
}
// 重写 onOptionsItemSelected 用以响应选项菜单
@Override
public boolean onOptionsItemSelected(MenuItem item) {
super.onOptionsItemSelected(item);
Toast.makeText(Main.this, "被单击的菜单项为：" + String.valueOf(item.getItemId()), Toast.LENGTH_SHORT).show();
return false;
}
}
Android(3) - 对话框(Dialog)和通知(Notification)
介绍
在 Android 中种对话框及各种通知效果的应用
· 常用对话框的使用，弹出式对话框、日期选择对话框、时间选择对话框、进度条对话框
· 通知（出现在通知列表）和提示性通知（Toast）的演示
1、常用对话框的演示
res/layout/main.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:id="@+id/txtMsg" android:layout_width="wrap_content"
android:layout_height="wrap_content"></TextView>
<Button android:id="@+id/btn1" android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
<Button android:id="@+id/btn2" android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
<Button android:id="@+id/btn3" android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
<Button android:id="@+id/btn4" android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
<Button android:id="@+id/btn5" android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
<Button android:id="@+id/btn6" android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
</LinearLayout>
res/layout/view.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:text="我是一个 View"
android:layout_width="wrap_content" android:layout_height="wrap_content">
</TextView>
</LinearLayout>
res/values/array.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<!--
定义一个名为 ary 的 string 类型的数组
-->
<string-array name="ary">
<item>项目 1</item>
<item>项目 2</item>
</string-array>
</resources>
Main.java
代码
package com.webabcd.dialog;
import java.util.Calendar;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.app.TimePickerDialog;
import android.app.DatePickerDialog.OnDateSetListener;
import android.app.TimePickerDialog.OnTimeSetListener;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.view.View;
import android.widget.DatePicker;
import android.widget.TextView;
import android.widget.TimePicker;
import android.widget.Button;
public class Main extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 弹出式对话框的 Demo。先调用 Builder()，在 Create()， 需要显示对话框的是后再调用 show()
AlertDialog dialog = new AlertDialog.Builder(this).setTitle("弹出对话框").create();
dialog.show();
// 以下是各种对话框的 Demo
MyButtonClickListener listener = new MyButtonClickListener();
Button btn1 = (Button) this.findViewById(R.id.btn1);
btn1.setText("简单的对话框的 Demo");
btn1.setOnClickListener(listener);
Button btn2 = (Button) this.findViewById(R.id.btn2);
btn2.setText("包括常用设置的对话框(数据来自 xml)");
btn2.setOnClickListener(listener);
Button btn3 = (Button) this.findViewById(R.id.btn3);
btn3.setText("弹出的对话框的内容是一个 View");
btn3.setOnClickListener(listener);
Button btn4 = (Button) this.findViewById(R.id.btn4);
btn4.setText("日期选择对话框");
btn4.setOnClickListener(listener);
Button btn5 = (Button) this.findViewById(R.id.btn5);
btn5.setText("时间选择对话框");
btn5.setOnClickListener(listener);
Button btn6 = (Button) this.findViewById(R.id.btn6);
btn6.setText("进度条对话框");
btn6.setOnClickListener(listener);
}
class MyButtonClickListener implements View.OnClickListener {
@Override
public void onClick(View v) {
// 具体的对话框的实现可以通过重写 onCreateDialog 完成
switch (v.getId()) {
case R.id.btn1:
Main.this.showDialog(0);
break;
case R.id.btn2:
Main.this.showDialog(1);
break;
case R.id.btn3:
Main.this.showDialog(2);
break;
case R.id.btn4:
Main.this.showDialog(3);
break;
case R.id.btn5:
Main.this.showDialog(4);
break;
case R.id.btn6:
Main.this.showDialog(5);
break;
}
}
}
@Override
public Dialog onCreateDialog(int id) {
switch (id) {
case 0:
// 一个简单的弹出对话框
return new AlertDialog.Builder(this).setTitle("这是一个简单的弹出对话框的 Demo")
.create();
case 1:
// 一个相对复杂的弹出对话框
return new AlertDialog.Builder(this)
.setTitle("标题") // 设置标题
// .setCustomTitle(View) // 以一个 View 作为标题
.setIcon(R.drawable.icon01) // 设置标题图片
// .setMessage("信息") // 需要显示的弹出内容
.setPositiveButton("确定", new OnClickListener() { // 设置弹框的确认按钮所显示的文本，以及单击按钮后的响应行为
@Override
public void onClick(DialogInterface a0, int a1) {
TextView txtMsg = (TextView) Main.this.findViewById(R.id.txtMsg);
txtMsg.append("单击了对话框上的“确认”按钮\n");
}
})
.setItems(R.array.ary, new DialogInterface.OnClickListener() { // 弹框所显示的内容来自一个数组。数组中的数据会一行一行地依次排列
public void onClick(DialogInterface dialog, int which) {
}
})
// 其他常用方法如下
// .setMultiChoiceItems(arg0, arg1, arg2)
// .setSingleChoiceItems(arg0, arg1, arg2)
// .setNeutralButton(arg0, arg1)
// .setNegativeButton(arg0, arg1)
.create();
case 2:
// 弹出对话框为指定的 View 的 Demo
return new AlertDialog.Builder(this).setTitle("此对话框的内容是一个 View")
.setView(this.findViewById(R.layout.view)).create();
case 3:
// 弹出日期选择对话框
Calendar c = Calendar.getInstance();
return new DatePickerDialog(this, new OnDateSetListener() {
@Override
public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
TextView txtMsg = (TextView) Main.this.findViewById(R.id.txtMsg);
txtMsg.append("新设置的日期为：" + String.valueOf(year) + "-"
+ String.valueOf(monthOfYear) + "-"
+ String.valueOf(dayOfMonth) + "\n");
}
}, c.get(Calendar.YEAR), c.get(Calendar.MONTH), c.get(Calendar.DATE));
case 4:
// 弹出时间选择对话框
Calendar c2 = Calendar.getInstance();
return new TimePickerDialog(this, new OnTimeSetListener() {
@Override
public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
TextView txtMsg = (TextView) Main.this.findViewById(R.id.txtMsg);
txtMsg.append("新设置的时间为："
+ String.valueOf(hourOfDay) + ":"
+ String.valueOf(minute) + "\n");
}
}, c2.get(Calendar.HOUR), c2.get(Calendar.MINUTE), true);
case 5:
// 弹出进度条对话框
ProgressDialog progress = new ProgressDialog(this);
progress.setMessage("loading...");
return progress;
default:
return null;
}
}
}
2、各种提示效果的演示
res/layout/main.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<Button android:id="@+id/btn1" android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
<Button android:id="@+id/btn2" android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
<Button android:id="@+id/btn3" android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
<Button android:id="@+id/btn4" android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
</LinearLayout>
res/layout/view.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:id="@+id/txtMsg" android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
Main.java
代码
package com.webabcd.notification;
import android.app.Activity;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class Main extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 通过 Tost.makeText().show() 来实现提示性的通知效果
// 短时间的提示性通知的 Demo
Button btn1 = (Button) this.findViewById(R.id.btn1);
btn1.setText("短时间提示");
btn1.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
Toast.makeText(Main.this, "我是短时间提示", Toast.LENGTH_SHORT).show();
}
});
// 长时间的提示性通知的 Demo
Button btn2 = (Button) this.findViewById(R.id.btn2);
btn2.setText("长时间提示");
btn2.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
Toast.makeText(Main.this, "我是长时间提示", Toast.LENGTH_LONG).show();
}
});
// 以一个 View 作为提示性通知的 Demo
Button btn3 = (Button) this.findViewById(R.id.btn3);
btn3.setText("以一个 View 做提示");
btn3.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
View view = inflateView(R.layout.view);
TextView txtMsg = (TextView) view.findViewById(R.id.txtMsg);
txtMsg.setText("提示内容");
Toast toast = new Toast(Main.this);
toast.setView(view);
toast.setDuration(Toast.LENGTH_LONG);
toast.show();
}
});
Button btn4 = (Button) this.findViewById(R.id.btn4);
btn4.setText("发出一个通知（Notification）");
btn4.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
// 实例化通知管理器
NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
// 指定单击通知后所打开的详细的通知页面（单击通知后打开 NotificationView）
PendingIntent contentIntent = PendingIntent.getActivity(
Main.this, 0, new Intent(Main.this, NotificationView.class), 0);
// 实例化一个通知，并指定其图标和标题（在提示栏上显示）
Notification n = new Notification(R.drawable.icon01, "我是滚动的通知信息我是滚动的通知信息我是滚动的通知信息", System.currentTimeMillis());
// 设置通知的发送人和通知的详细内容（打开提示栏后在通知列表中显示）
n.setLatestEventInfo(Main.this, "通知发送人", "我是详细的通知信息我是详细的通知信息我是详细的通知信息", contentIntent);
// 100 毫秒延迟后，震动 250 毫秒，暂停 100 毫秒后，再震动 500 毫秒
n.vibrate = new long[] { 100, 250, 100, 500 };
// 发出通知（其中第一个参数为通知标识符）
nm.notify(0, n);
}
});
}
// 将指定的 xml 资源转换为一个 View
private View inflateView(int resource) {
LayoutInflater vi = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
return vi.inflate(resource, null);
}
// 打开详细通知页后此 Activity 会被 Pause，从详细通知页返回后此 Activity 会被 Resume
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
Log.d("MyDebug", "onPause");
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
Log.d("MyDebug", "onResume");
}
}
NotificationView.java
代码
package com.webabcd.notification;
import android.app.Activity;
import android.app.NotificationManager;
import android.os.Bundle;
import android.widget.TextView;
// 单击通知列表的某个通知后，所打开的详细的通知页
public class NotificationView extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.view);
TextView txtMsg = (TextView)this.findViewById(R.id.txtMsg);
txtMsg.setText("点通知之后所链接到的 Activity");
NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
// 取消显示在通知列表中的指定通知（参数为通知标识符）
nm.cancel(0);
// 需要关闭此 Activity 的话就 finish 它既可
// this.finish();
}
}
Android(4) - 活动(Activity), 服务(Service), 广播(Broadcast), 广播接收器(BroadcastReceiver)
介绍
在 Android 中使用 Activity, Service, Broadcast, BroadcastReceiver
活动(Activity) - 用于表现功能
服务(Service) - 相当于后台运行的 Activity
广播(Broadcast) - 用于发送广播
广播接收器(BroadcastReceiver) - 用于接收广播
Intent - 用于连接以上各个组件，并在其间传递消息
1、演示 Activity 的基本用法，一个 Activity 启动另一个 Activity，启动另一个 Activity 时为其传递参数，被启动的 Activity 返回参数给启动者的 Activity
Main.java
代码
package com.webabcd.activity;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class Main extends Activity {
TextView txt;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.main);
txt = (TextView) this.findViewById(R.id.txt);
txt.setText("Activity 1");
Button btn = (Button) this.findViewById(R.id.btn);
btn.setText("启动另一个Activity");
btn.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View v) {
// 实例化 Intent，指定需要启动的 Activity
Intent intent = new Intent();
intent.setClass(Main.this, MyActivity.class);
// 实例化 Bundle，设置需要传递的参数
Bundle bundle = new Bundle();
bundle.putString("name", "webabcd");
bundle.putDouble("salary", 100.13);
// 将需要传递的参数赋值给 Intent 对象
intent.putExtras(bundle);
// startActivity(intent); // 启动指定的 Intent（不等待返回结果）
// Main.this.finish();
// 启动指定的 Intent，并等待返回结果
// 其中第二个参数如果大于等于零，则返回结果时会回调 onActivityResult() 方法
startActivityForResult(intent, 0);
}
});
Log.d("MyDebug", "onCreate");
}
// 被启动的 Activity 返回结果时的回调函数
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode == Activity.RESULT_OK){
Bundle bundle = data.getExtras();
String name = bundle.getString("name");
double salary = bundle.getDouble("salary");
txt.setText("Activity 1" + "\n名字：" + name + "\n薪水：" + String.valueOf(salary));
}
}
@Override
protected void onStart() {
// TODO Auto-generated method stub
super.onStart();
Log.d("MyDebug", "onStart");
}
@Override
protected void onStop() {
// TODO Auto-generated method stub
super.onStop();
Log.d("MyDebug", "onStop");
}
@Override
protected void onRestart() {
// TODO Auto-generated method stub
super.onRestart();
Log.d("MyDebug", "onRestart");
}
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
Log.d("MyDebug", "onPause");
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
Log.d("MyDebug", "onResume");
}
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
Log.d("MyDebug", "onDestroy");
}
}
MyActivity.java
代码
package com.webabcd.activity;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
// 被另一个 Activity 所启动的 Activity
public class MyActivity extends Activity {
Intent intent;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.main2);
// 获取启动者传递过来的参数
intent = this.getIntent();
Bundle bundle = intent.getExtras();
String name = bundle.getString("name");
double salary = bundle.getDouble("salary");
TextView txt = (TextView) this.findViewById(R.id.txt);
txt.setText("Activity 2" + "\n名字：" + name + "\n薪水：" + String.valueOf(salary));
Button btn = (Button) this.findViewById(R.id.btn);
btn.setText("返回前一个Activity");
btn.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
// 返回参数给启动者
MyActivity.this.setResult(Activity.RESULT_OK, intent);
MyActivity.this.finish();
}
});
}
}
AndroidManifest.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.webabcd.activity" android:versionCode="1"
android:versionName="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".Main" android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<!--
如果有需要用到的 Activity ，则都要在这里做相应的配置
-->
<activity android:name=".MyActivity" android:label="Activity 2" />
</application>
<uses-sdk android:minSdkVersion="3" />
</manifest>
2、Service, Broadcast, BroadcastReceiver 的演示
Main.java
代码
package com.webabcd.service;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;
/*
* startService() 和 bindService() 的区别
* startService() - 正常理解就好
* bindService() - 使当前上下文对象（本例中就是 Activity）通过一个 ServiceConnection 对象邦定到指定的 Service 。这样，如果上下文对象销毁了的话，那么其对应的 Service 也会被销毁
*/
public class Main extends Activity implements OnClickListener {
private TextView txtMsg;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
setTitle("android 之 service");
this.findViewById(R.id.btnStart).setOnClickListener(this);
this.findViewById(R.id.btnStop).setOnClickListener(this);
this.findViewById(R.id.btnBind).setOnClickListener(this);
this.findViewById(R.id.btnUnbind).setOnClickListener(this);
txtMsg = (TextView)this.findViewById(R.id.txtMsg);
// 实例化自定义的 BroadcastReceiver
receiver = new UpdateReceiver();
IntentFilter filter = new IntentFilter();
// 为 BroadcastReceiver 指定 action ，使之用于接收同 action 的广播
filter.addAction("com.webabcd.service.msg");
// 以编程方式注册 BroadcastReceiver 。配置方式注册 BroadcastReceiver 的例子见 AndroidManifest.xml 文件
// 一般在 OnStart 时注册，在 OnStop 时取消注册
this.registerReceiver(receiver, filter);
// this.unregisterReceiver(receiver);
}
@Override
public void onClick(View v) {
Intent intent = new Intent(Main.this, MyService.class);
switch (v.getId()) {
case R.id.btnStart:
this.startService(intent);
break;
case R.id.btnStop:
this.stopService(intent);
break;
case R.id.btnBind:
this.bindService(intent, conn, Context.BIND_AUTO_CREATE);
break;
case R.id.btnUnbind:
this.unbindService(conn);
break;
}
}
// bindService() 所需的 ServiceConnection 对象
private ServiceConnection conn = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName className, IBinder service) {
}
@Override
public void onServiceDisconnected(ComponentName className) {
}
};
private String msg="";
private UpdateReceiver receiver;
// 实现一个 BroadcastReceiver，用于接收指定的 Broadcast
public class UpdateReceiver extends BroadcastReceiver{
@Override
public void onReceive(Context context, Intent intent) {
msg = intent.getStringExtra("msg");
txtMsg.append(msg + "\n");
}
}
}
MyService.java
代码
package com.webabcd.service;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;
// 演示 Service 的生命周期。具体信息运行程序后在 LogCat 中查看
public class MyService extends Service {
@Override
public IBinder onBind(Intent intent) {
Log.d("MyDebug", "onBind");
sendMsg("onBind");
// TODO Auto-generated method stub
return null;
}
@Override
public void onCreate() {
// TODO Auto-generated method stub
super.onCreate();
Log.d("MyDebug", "onCreate");
sendMsg("onCreate");
}
@Override
public void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
Log.d("MyDebug", "onDestroy");
sendMsg("onDestroy");
}
@Override
public void onRebind(Intent intent) {
// TODO Auto-generated method stub
super.onRebind(intent);
Log.d("MyDebug", "onRebind");
sendMsg("onRebind");
}
@Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
Log.d("MyDebug", "onStart");
sendMsg("onStart");
}
@Override
public boolean onUnbind(Intent intent) {
Log.d("MyDebug", "onUnbind");
sendMsg("onUnbind");
// TODO Auto-generated method stub
return super.onUnbind(intent);
}
// 发送广播信息
private void sendMsg(String msg){
// 指定广播目标的 action （注：指定了此 action 的 receiver 会接收此广播）
Intent intent = new Intent("com.webabcd.service.msg");
// 需要传递的参数
intent.putExtra("msg", msg);
// 发送广播
this.sendBroadcast(intent);
}
}
MyBootReceiver.java
代码
package com.webabcd.service;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
public class MyBootReceiver extends BroadcastReceiver {
// 用于接收满足条件的 Broadcast（相应的 Broadcast 的注册信息详见 AndroidManifest.xml ，当系统启动完毕后会调用这个广播接收器）
@Override
public void onReceive(Context arg0, Intent arg1) {
Log.d("MyDebug", "onReceive");
// 启动服务
Intent service = new Intent(arg0, MyService.class);
arg0.startService(service);
}
}
AndroidManifest.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.webabcd.service" android:versionCode="1"
android:versionName="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".Main" android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<!--
如果有需要用到的 service ，则都要在这里做相应的配置
-->
<service android:name=".MyService"></service>
<!--
注册一个 BroadcastReceiver
其 intent-filter 为 android.intent.action.BOOT_COMPLETED（用于接收系统启动完毕的 Broadcast）
-->
<receiver android:name=".MyBootReceiver">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
</application>
<!--
接受系统启动完毕的 Broadcast 的权限
-->
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-sdk android:minSdkVersion="3" />
</manifest>
Android(5) - 控件(View)之TextView, Button, ImageButton, ImageView, CheckBox, RadioButton, AnalogClock, DigitalClock
介绍
在 Android 中使用各种控件(View)
· TextView - 文本显示控件
· Button - 按钮控件
· ImageButton - 图片按钮控件
· ImageView - 图片显示控件
· CheckBox - 复选框控件
· RadioButton - 单选框控件
· AnalogClock - 钟表（带表盘的那种）控件
· DigitalClock - 电子表控件
1、TextView 的 Demo
textview.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
TextView - 文本显示控件
-->
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content" android:id="@+id/textView" />
</LinearLayout>
_TextView.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class _TextView extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.textview);
// 设置 Activity 的标题
setTitle("TextView");
TextView txt = (TextView) this.findViewById(R.id.textView);
// 设置文本显示控件的文本内容，需要换行的话就用“\n”
txt.setText("我是 TextView\n显示文字用的");
}
}
2、Button 的 Demo
button.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content" android:id="@+id/textView" />
<!--
Button - 按钮控件
-->
<Button android:id="@+id/button"
android:layout_width="wrap_content" android:layout_height="wrap_content">
</Button>
</LinearLayout>
_Button.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class _Button extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.button);
setTitle("Button");
Button btn = (Button) this.findViewById(R.id.button);
btn.setText("click me");
// setOnClickListener() - 响应按钮的鼠标单击事件
btn.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View v) {
TextView txt = (TextView) _Button.this.findViewById(R.id.textView);
txt.setText("按钮被单击了");
}
});
}
}
3、ImageButton 的 Demo
imagebutton.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content" android:id="@+id/textView" />
<!--
ImageButton - 图片按钮控件
-->
<ImageButton android:id="@+id/imageButton"
android:layout_width="wrap_content" android:layout_height="wrap_content">
</ImageButton>
</LinearLayout>
_ImageButton.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.TextView;
public class _ImageButton extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.imagebutton);
setTitle("ImageButton");
ImageButton imgButton = (ImageButton) this.findViewById(R.id.imageButton);
// 设置图片按钮的背景
imgButton.setBackgroundResource(R.drawable.icon01);
// setOnClickListener() - 响应图片按钮的鼠标单击事件
imgButton.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View v) {
TextView txt = (TextView) _ImageButton.this.findViewById(R.id.textView);
txt.setText("图片按钮被单击了");
}
});
}
}
4、ImageView 的 Demo
imageview.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
ImageView - 图片显示控件
-->
<ImageView android:id="@+id/imageView" android:layout_width="wrap_content"
android:layout_height="wrap_content"></ImageView>
</LinearLayout>
_ImageView.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.widget.ImageView;
public class _ImageView extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.imageview);
setTitle("ImageView");
ImageView imgView = (ImageView) this.findViewById(R.id.imageView);
// 指定需要显示的图片
imgView.setBackgroundResource(R.drawable.icon01);
}
}
5、CheckBox 的 Demo
checkbox.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content" android:id="@+id/textView" />
<!--
CheckBox - 复选框控件
-->
<CheckBox android:text="CheckBox01" android:id="@+id/chk1"
android:layout_width="wrap_content" android:layout_height="wrap_content"></CheckBox>
<CheckBox android:text="CheckBox02" android:id="@+id/chk2"
android:layout_width="wrap_content" android:layout_height="wrap_content"></CheckBox>
<CheckBox android:text="CheckBox03" android:id="@+id/chk3"
android:layout_width="wrap_content" android:layout_height="wrap_content"></CheckBox>
</LinearLayout>
_CheckBox.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.TextView;
public class _CheckBox extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.checkbox);
setTitle("CheckBox");
CheckBox chk = (CheckBox) this.findViewById(R.id.chk1);
// setOnCheckedChangeListener() - 响应复选框的选中状态改变事件
chk.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
TextView txt = (TextView) _CheckBox.this.findViewById(R.id.textView);
txt.setText("CheckBox01 的选中状态：" + String.valueOf(isChecked));
}
});
}
}
6、RadioButton 的 Demo
radiobutton.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content" android:id="@+id/textView" />
<!--
RadioButton - 单选框控件
RadioGroup - 对其内的单选框控件做分组
checkedButton - 指定组内被选中的单选框的 ID
-->
<RadioGroup android:id="@+id/radioGroup"
android:layout_width="fill_parent" android:layout_height="fill_parent"
android:checkedButton="@+id/rad3" android:orientation="horizontal"
android:gravity="center_vertical|center_horizontal">
<RadioButton android:text="rad1" android:id="@+id/rad1"
android:layout_width="wrap_content" android:layout_height="wrap_content"></RadioButton>
<RadioButton android:text="rad2" android:id="@+id/rad2"
android:layout_width="wrap_content" android:layout_height="wrap_content"></RadioButton>
<RadioButton android:text="rad3" android:id="@+id/rad3"
android:layout_width="wrap_content" android:layout_height="wrap_content"></RadioButton>
</RadioGroup>
</LinearLayout>
_RadioButton.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
public class _RadioButton extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.radiobutton);
setTitle("RadioButton");
RadioGroup group = (RadioGroup) this.findViewById(R.id.radioGroup);
// setOnCheckedChangeListener() - 响应单选框组内的选中项发生变化时的事件
group.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
TextView txt = (TextView) _RadioButton.this.findViewById(R.id.textView);
txt.setText(((RadioButton)findViewById(checkedId)).getText() + " 被选中");
}
});
}
}
7、AnalogClock 的 Demo
analogclock.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
AnalogClock - 钟表（带表盘的那种）控件
-->
<AnalogClock android:id="@+id/analogClock"
android:layout_width="wrap_content" android:layout_height="wrap_content">
</AnalogClock>
</LinearLayout>
_AnalogClock.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
public class _AnalogClock extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.analogclcok);
setTitle("AnalogClock");
}
}
8、DigitalClock 的 Demo
digitalclock.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
DigitalClock - 电子表控件
-->
<DigitalClock android:id="@+id/digitalClock"
android:layout_width="wrap_content" android:layout_height="wrap_content">
</DigitalClock>
</LinearLayout>
_DigitalClock.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
public class _DigitalClock extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.digitalclcok);
setTitle("DigitalClcok");
}
}
Android(6) - 控件(View)之DatePicker, TimePicker, ToggleButton, EditText, ProgressBar, SeekBar, AutoCompleteTextView, MultiAutoCompleteTextView
介绍
在 Android 中使用各种控件(View)
· DatePicker - 日期选择控件
· TimePicker - 时间选择控件
· ToggleButton - 双状态按钮控件
· EditText - 可编辑文本控件
· ProgressBar - 进度条控件
· SeekBar - 可拖动的进度条控件
· AutoCompleteTextView - 支持自动完成功能的可编辑文本控件
· MultiAutoCompleteTextView - 支持自动完成功能的可编辑文本控件，允许输入多值（多值之间会自动地用指定的分隔符分开）
1、DatePicker 的 Demo
datepicker.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
DatePicker - 日期选择控件
-->
<DatePicker android:id="@+id/datePicker"
android:layout_width="wrap_content" android:layout_height="wrap_content">
</DatePicker>
</LinearLayout>
_DatePicker.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
public class _DatePicker extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.datepicker);
// 具体的应用可参见对话框中的示例
setTitle("DatePicker");
}
}
2、TimePicker 的 Demo
timepicker.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
TimePicker - 时间选择控件
-->
<TimePicker android:id="@+id/timePicker"
android:layout_width="wrap_content" android:layout_height="wrap_content">
</TimePicker>
</LinearLayout>
_TimePicker.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
public class _TimePicker extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.timepicker);
// 具体的应用可参见对话框中的示例
setTitle("TimePicker");
}
}
3、ToggleButton 的 Demo
togglebutton.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content" android:id="@+id/textView" />
<!--
ToggleButton - 双状态按钮控件
textOn - 当按钮状态为 true 时所显示的文本
textOff - 当按钮状态为 false 时所显示的文本
-->
<ToggleButton android:id="@+id/toggleButton"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:textOn="关闭" android:textOff="打开" />
</LinearLayout>
_ToggleButton.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.ToggleButton;
public class _ToggleButton extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.togglebutton);
setTitle("ToggleButton");
final ToggleButton btn = (ToggleButton) this.findViewById(R.id.toggleButton);
// setOnClickListener() - 响应按钮的鼠标单击事件
btn.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View v) {
TextView txt = (TextView) _ToggleButton.this.findViewById(R.id.textView);
// ToggleButton.isChecked() - 双状态按钮的按钮状态
txt.setText("按钮状态：" + String.valueOf(btn.isChecked()));
}
});
}
}
4、EditText 的 Demo
edittext.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
EditText - 可编辑文本控件
-->
<EditText android:id="@+id/editText" android:layout_width="fill_parent"
android:layout_height="wrap_content">
</EditText>
</LinearLayout>
_EditText.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.widget.EditText;
public class _EditText extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.edittext);
setTitle("EditText");
EditText txt = (EditText) this.findViewById(R.id.editText);
txt.setText("我可编辑");
}
}
5、ProgressBar 的 Demo
progressbar.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
ProgressBar - 进度条控件
-->
<!--以下分别为大、中、小的进度条控件（圆圈状）-->
<ProgressBar android:id="@+android:id/progress_large"
style="?android:attr/progressBarStyleLarge" android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<ProgressBar android:id="@+android:id/progress"
android:layout_width="wrap_content" android:layout_height="wrap_content" />
<ProgressBar android:id="@+android:id/progress_small"
style="?android:attr/progressBarStyleSmall" android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<!--
进度条控件（条状）的演示
style - 进度条的样式，本例使用内置样式
max - 进度的最大值
progress - 第一进度位置
secondaryProgress - 第二进度位置
-->
<ProgressBar android:id="@+id/progress_horizontal"
style="?android:attr/progressBarStyleHorizontal" android:layout_width="200px"
android:layout_height="wrap_content" android:max="100"
android:progress="50" android:secondaryProgress="75" />
</LinearLayout>
_ProgressBar.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.view.Window;
// 另见对话框中的进度条
public class _ProgressBar extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
// 设置特性以允许在应用程序的标题栏上显示进度条（条状）
requestWindowFeature(Window.FEATURE_PROGRESS);
// 设置特性以允许在应用程序的标题栏上显示进度条（圆圈状）
requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
this.setContentView(R.layout.progressbar);
setTitle("ProgressBar");
// 在标题栏上显示进度条（条状）
setProgressBarVisibility(true);
// 在标题栏上显示进度条（圆圈状）
setProgressBarIndeterminateVisibility(true);
// 指定进度条的进度
setProgress(50 * 100);
setSecondaryProgress(75 * 100);
}
}
6、SeekBar 的 Demo
seekbar.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
SeekBar - 可拖动的进度条控件
max - 进度的最大值
progress - 第一进度位置
secondaryProgress - 第二进度位置
-->
<SeekBar android:id="@+id/seekBar" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:max="100"
android:progress="50" android:secondaryProgress="75" />
<TextView android:id="@+id/progress" android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<TextView android:id="@+id/tracking" android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>
_SeekBar.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.widget.SeekBar;
import android.widget.TextView;
public class _SeekBar extends Activity implements
SeekBar.OnSeekBarChangeListener {
SeekBar mSeekBar;
TextView mProgressText;
TextView mTrackingText;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.seekbar);
setTitle("SeekBar");
mSeekBar = (SeekBar) findViewById(R.id.seekBar);
// setOnSeekBarChangeListener() - 响应拖动进度条事件
mSeekBar.setOnSeekBarChangeListener(this);
mProgressText = (TextView) findViewById(R.id.progress);
mTrackingText = (TextView) findViewById(R.id.tracking);
}
// 拖动进度条后，进度发生改变时的回调事件
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromTouch) {
mProgressText.setText(progress + "%");
}
// 拖动进度条前开始跟踪触摸
public void onStartTrackingTouch(SeekBar seekBar) {
mTrackingText.setText("开始跟踪触摸");
}
// 拖动进度条后停止跟踪触摸
public void onStopTrackingTouch(SeekBar seekBar) {
mTrackingText.setText("停止跟踪触摸");
}
}
7、AutoCompleteTextView 的 Demo
autocompletetextview.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
AutoCompleteTextView - 支持自动完成功能的可编辑文本控件
-->
<AutoCompleteTextView android:id="@+id/editText"
android:layout_width="fill_parent" android:layout_height="wrap_content" />
</LinearLayout>
_AutoCompleteTextView.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
public class _AutoCompleteTextView extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.autocompletetextview);
setTitle("AutoCompleteTextView");
// 实例化适配器，指定显示格式及数据源
ArrayAdapter<String> adapter = new ArrayAdapter<String>(
this,
android.R.layout.simple_dropdown_item_1line,
ary);
AutoCompleteTextView textView = (AutoCompleteTextView) findViewById(R.id.editText);
// 指定自动完成控件的适配器
textView.setAdapter(adapter);
}
// 自动完成控件的所需数据的数据源
private String[] ary = new String[] {
"abc",
"abcd",
"abcde",
"abcdef",
"abcdefg",
"hij",
"hijk",
"hijkl",
"hijklm",
"hijklmn",
};
}
8、MultiAutoCompleteTextView 的 Demo
multiautocompletetextview.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
MultiAutoCompleteTextView - 支持自动完成功能的可编辑文本控件，允许输入多值（多值之间会自动地用指定的分隔符分开）
-->
<MultiAutoCompleteTextView android:id="@+id/editText"
android:layout_width="fill_parent" android:layout_height="wrap_content" />
</LinearLayout>
_MultiAutoCompleteTextView.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.MultiAutoCompleteTextView;
public class _MultiAutoCompleteTextView extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.multiautocompletetextview);
setTitle("MultiAutoCompleteTextView");
// 实例化适配器，指定显示格式及数据源
ArrayAdapter<String> adapter = new ArrayAdapter<String>(
this,
android.R.layout.simple_dropdown_item_1line,
ary);
MultiAutoCompleteTextView textView = (MultiAutoCompleteTextView) findViewById(R.id.editText);
textView.setAdapter(adapter);
// 设置多个值之间的分隔符，此处为逗号
textView.setTokenizer(new MultiAutoCompleteTextView.CommaTokenizer());
}
// 自动完成控件的所需数据的数据源
private String[] ary = new String[] {
"abc",
"abcd",
"abcde",
"abcdef",
"abcdefg",
"hij",
"hijk",
"hijkl",
"hijklm",
"hijklmn",
};
}
Android(7) - 控件(View)之ZoomControls, Include, VideoView, WebView, RatingBar, Tab, Spinner, Chronometer, ScrollView
介绍
在 Android 中使用各种控件(View)
· ZoomControls - 放大/缩小按钮控件
· Include - 整合控件
· VideoView - 视频播放控件
· WebView - 浏览器控件
· RatingBar - 评分控件
· Tab - 选项卡控件
· Spinner - 下拉框控件
· Chronometer - 计时器控件
· ScrollView - 滚动条控件
1、ZoomControls 的 Demo
zoomcontrols.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
放大/缩小按钮控件
-->
<ZoomControls android:id="@+id/zoomControls"
android:layout_width="wrap_content" android:layout_height="wrap_content"></ZoomControls>
</LinearLayout>
_ZoomControls.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Toast;
import android.widget.ZoomControls;
public class _ZoomControls extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.zoomcontrols);
setTitle("ZoomControls");
ZoomControls zoomControls = (ZoomControls) this.findViewById(R.id.zoomControls);
// setOnZoomInClickListener() - 响应单击放大按钮的事件
zoomControls.setOnZoomInClickListener(new OnClickListener() {
public void onClick(View v) {
Toast.makeText(_ZoomControls.this, "单击了放大按钮", Toast.LENGTH_SHORT).show();
}
});
// setOnZoomOutClickListener() - 响应单击缩小按钮的事件
zoomControls.setOnZoomOutClickListener(new OnClickListener() {
public void onClick(View v) {
Toast.makeText(_ZoomControls.this, "单击了缩小按钮", Toast.LENGTH_SHORT).show();
}
});
}
}
2、Include 的 Demo
include.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
include - 整合控件，将指定的 layout 整合进来
layout - 指定需要整合 layout
-->
<include android:id="@+id/cell1" layout="@layout/include_1" />
<include android:id="@+id/cell2" android:layout_width="fill_parent" layout="@layout/include_2" />
</LinearLayout>
include_1.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:text="TextView01" android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
include_2.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:text="TextView02" android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
_Include.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
public class _Include extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.include);
setTitle("Include");
}
}
3、VideoView 的 Demo
videoview.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
VideoView - 视频播放控件
-->
<VideoView android:id="@+id/videoView" android:layout_width="wrap_content"
android:layout_height="wrap_content">
</VideoView>
</LinearLayout>
_VideoView.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.net.Uri;
import android.os.Bundle;
import android.widget.MediaController;
import android.widget.VideoView;
public class _VideoView extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.videoview);
setTitle("VideoView");
VideoView videoView = (VideoView) findViewById(R.id.videoView);
// 指定需要播放的视频的地址
videoView.setVideoURI(Uri.parse("android.resource://com.webabcd.view/" + R.raw.demo));
// videoView.setVideoPath();
// 设置播放器的控制条
videoView.setMediaController(new MediaController(this));
// 开始播放视频
videoView.start();
}
}
4、WebView 的 Demo
webview.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
WebView - 浏览器控件（WebKit 内核）
-->
<WebView android:layout_width="fill_parent"
android:layout_height="wrap_content" android:id="@+id/webView" />
</LinearLayout>
_WebView.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.webkit.WebSettings;
import android.webkit.WebView;
public class _WebView extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.webview);
setTitle("WebView");
WebView webView = (WebView) findViewById(R.id.webView);
// 配置浏览器，使其可支持 JavaScript
WebSettings webSettings = webView.getSettings();
webSettings.setJavaScriptEnabled(true);
// 清除浏览器缓存
webView.clearCache(true);
// 指定浏览器需要解析的 url 地址
webView.loadUrl("http://webabcd.cnblogs.com/");
// 指定浏览器需要解析的 html 数据
// webView.loadData("<a href='http://webabcd.cnblogs.com/'>webabcd</a>", "text/html", "utf-8");
}
}
5、RatingBar 的 Demo
ratingbar.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
RatingBar - 评分控件
numStars - 评分控件的星星的数量
rating - 当前评分的值
-->
<RatingBar android:id="@+id/ratingBar" android:numStars="5"
android:rating="1.5" android:layout_width="wrap_content"
android:layout_height="wrap_content">
</RatingBar>
<TextView android:id="@+id/textView" android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
_RatingBar.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.widget.RatingBar;
import android.widget.TextView;
public class _RatingBar extends Activity implements RatingBar.OnRatingBarChangeListener {
private RatingBar mRatingBar;
private TextView mTextView;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.ratingbar);
setTitle("RatingBar");
mTextView = (TextView) findViewById(R.id.textView);
mRatingBar = (RatingBar) findViewById(R.id.ratingBar);
// setOnRatingBarChangeListener() - 响应评分值发生改变的事件
mRatingBar.setOnRatingBarChangeListener(this);
}
@Override
public void onRatingChanged(RatingBar ratingBar, float rating,
boolean fromUser) {
mTextView.setText(String.valueOf(rating));
}
}
6、Tab 的 Demo
tab.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="fill_parent">
<!-- Tab 1 的内容 -->
<TextView android:id="@+id/view1" android:layout_width="fill_parent"
android:layout_height="fill_parent" android:text="tab1 content" />
<!-- Tab 2 的内容 -->
<TextView android:id="@+id/view2" android:layout_width="fill_parent"
android:layout_height="fill_parent" android:text="tab2 content" />
</FrameLayout>
_Tab.java
代码
package com.webabcd.view;
import android.app.TabActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.widget.TabHost;
// 实现 Tab 功能的话要继承 TabActivity
public class _Tab extends TabActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
TabHost tabHost = getTabHost();
LayoutInflater.from(this).inflate(R.layout.tab, tabHost.getTabContentView(), true);
// Tab 1 的内容
tabHost.addTab(tabHost.newTabSpec("tab1")
.setIndicator("tab1")
.setContent(R.id.view1));
// Tab 2 的内容（设置了 Tab 图片）
tabHost.addTab(tabHost.newTabSpec("tab2")
.setIndicator("tab2", getResources().getDrawable(R.drawable.icon01))
.setContent(R.id.view2));
// Tab 3 的内容（设置 Tab 的内容为指定的 Activity）
tabHost.addTab(tabHost.newTabSpec("tab3")
.setIndicator("tab3")
.setContent(new Intent(this, _TextView.class)));
}
}
7、Spinner 的 Demo
spinner.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content" android:id="@+id/textView" />
<!--
Spinner - 下拉框控件
-->
<Spinner android:id="@+id/spinner" android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>
_Spinner.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;
public class _Spinner extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.spinner);
setTitle("Spinner");
Spinner spinner = (Spinner) findViewById(R.id.spinner);
// 设置下拉框控件的标题文本
spinner.setPrompt("请选择");
// 实例化适配器，指定显示格式及数据源
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
this, R.array.colors, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
// setOnItemSelectedListener() - 响应下拉框的选中值发生变化的事件
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> arg0, View arg1,
int arg2, long arg3) {
TextView textView = (TextView)_Spinner.this.findViewById(R.id.textView);
textView.setText(((TextView)arg1).getText());
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
}
}
8、Chronometer 的 Demo
chronometer.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
Chronometer - 计时器控件
-->
<Chronometer android:id="@+id/chronometer"
android:layout_width="wrap_content" android:layout_height="wrap_content" />
<Button android:id="@+id/btnStart" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="开始计时">
<requestFocus />
</Button>
<Button android:id="@+id/btnStop" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="停止计时">
</Button>
<Button android:id="@+id/btnReset" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="计时器复位">
</Button>
</LinearLayout>
_Chronometer.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.os.SystemClock;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Chronometer;
public class _Chronometer extends Activity {
private Chronometer mChronometer;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.chronometer);
setTitle("Chronometer");
Button button;
mChronometer = (Chronometer) findViewById(R.id.chronometer);
// 设置计时器所显示的时间格式
mChronometer.setFormat("计时：(%s)");
button = (Button) findViewById(R.id.btnStart);
button.setOnClickListener(mStartListener);
button = (Button) findViewById(R.id.btnStop);
button.setOnClickListener(mStopListener);
button = (Button) findViewById(R.id.btnReset);
button.setOnClickListener(mResetListener);
}
View.OnClickListener mStartListener = new OnClickListener() {
public void onClick(View v) {
// 启动计时器
mChronometer.start();
}
};
View.OnClickListener mStopListener = new OnClickListener() {
public void onClick(View v) {
// 暂停计时器
mChronometer.stop();
}
};
View.OnClickListener mResetListener = new OnClickListener() {
public void onClick(View v) {
// 复位计时器，即停止计时器
mChronometer.setBase(SystemClock.elapsedRealtime());
}
};
}
9、ScrollView 的 Demo
scrollview.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
ScrollView - 滚动条控件
scrollbarStyle - 滚动条的样式
-->
<ScrollView android:id="@+id/scrollView"
android:layout_width="fill_parent" android:layout_height="200px"
android:scrollbarStyle="outsideOverlay" android:background="@android:drawable/edit_text">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content" android:id="@+id/textView" />
</ScrollView>
</LinearLayout>
_ScrollView.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class _ScrollView extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.scrollview);
setTitle("ScrollView");
TextView textView = (TextView)this.findViewById(R.id.textView);
textView.setText("a\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na\na");
}
}
Android(8) - 控件(View)之TextSwitcher, Gallery, ImageSwitcher, GridView, ListView, ExpandableList
介绍
在 Android 中使用各种控件(View)
· TextSwitcher - 文字转换器控件（改变文字时增加一些动画效果）
· Gallery - 缩略图浏览器控件
· ImageSwitcher - 图片转换器控件（改变图片时增加一些动画效果）
· GridView - 网格控件
· ListView - 列表控件
· ExpandableList - 支持展开/收缩功能的列表控件
1、TextSwitcher 的 Demo
textswitcher.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<Button android:id="@+id/btnChange" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="改变文字" />
<!--
TextSwitcher - 文字转换器控件（改变文字时增加一些动画效果）
-->
<TextSwitcher android:id="@+id/textSwitcher"
android:layout_width="fill_parent" android:layout_height="wrap_content" />
</LinearLayout>
_TextSwitcher.java
代码
package com.webabcd.view;
import java.util.Random;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.TextSwitcher;
import android.widget.TextView;
import android.widget.ViewSwitcher;
public class _TextSwitcher extends Activity implements ViewSwitcher.ViewFactory {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.textswithcer);
setTitle("TextSwithcer");
final TextSwitcher switcher = (TextSwitcher) findViewById(R.id.textSwitcher);
// 指定转换器的 ViewSwitcher.ViewFactory
switcher.setFactory(this);
// 设置淡入和淡出的动画效果
Animation in = AnimationUtils.loadAnimation(this, android.R.anim.fade_in);
Animation out = AnimationUtils.loadAnimation(this, android.R.anim.fade_out);
switcher.setInAnimation(in);
switcher.setOutAnimation(out);
// 单击一次按钮改变一次文字
Button btnChange = (Button) this.findViewById(R.id.btnChange);
btnChange.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
switcher.setText(String.valueOf(new Random().nextInt()));
}
});
}
// 重写 ViewSwitcher.ViewFactory 的 makeView()，返回一个 View
@Override
public View makeView() {
TextView textView = new TextView(this);
textView.setTextSize(36);
return textView;
}
}
2、Gallery 的 Demo
gallery.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<!--
Gallery - 缩略图浏览器控件
spacing - 缩略图列表中各个缩略图之间的间距
-->
<Gallery android:id="@+id/gallery" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:spacing="20px" />
</LinearLayout>
_Gallery.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;
import android.widget.Toast;
import android.widget.Gallery.LayoutParams;
public class _Gallery extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.gallery);
setTitle("Gallery");
Gallery gallery = (Gallery) findViewById(R.id.gallery);
// 为缩略图浏览器指定一个适配器
gallery.setAdapter(new ImageAdapter(this));
// 响应 在缩略图列表上选中某个缩略图后的 事件
gallery.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View v,
int position, long id) {
Toast.makeText(_Gallery.this, String.valueOf(position), Toast.LENGTH_SHORT).show();
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
}
// 继承 BaseAdapter 用以实现自定义的图片适配器
public class ImageAdapter extends BaseAdapter {
private Context mContext;
public ImageAdapter(Context context) {
mContext = context;
}
public int getCount() {
return mThumbIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView image = new ImageView(mContext);
image.setImageResource(mThumbIds[position]);
image.setAdjustViewBounds(true);
image.setLayoutParams(new Gallery.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
return image;
}
}
// 需要显示的图片集合
private Integer[] mThumbIds = { R.drawable.icon01, R.drawable.icon02,
R.drawable.icon03, R.drawable.icon04, R.drawable.icon05 };
}
3、ImageSwitcher 的 Demo
imageswitcher.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<Gallery android:id="@+id/gallery" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:spacing="20px" />
<!--
ImageSwitcher - 图片转换器控件（改变图片时增加一些动画效果）
-->
<ImageSwitcher android:id="@+id/imageSwitcher"
android:layout_width="fill_parent" android:layout_height="wrap_content" />
</LinearLayout>
_ImageSwitcher.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher;
import android.widget.Gallery.LayoutParams;
// 图片转换器的使用基本同文字转换器
// 以下是一个用 ImageSwitcher + Gallery 实现的经典的图片浏览器的 Demo
public class _ImageSwitcher extends Activity implements
ViewSwitcher.ViewFactory {
private ImageSwitcher mSwitcher;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.imageswithcer);
setTitle("ImageSwithcer");
mSwitcher = (ImageSwitcher) findViewById(R.id.imageSwitcher);
mSwitcher.setFactory(this);
mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_in));
mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_out));
Gallery gallery = (Gallery) findViewById(R.id.gallery);
gallery.setAdapter(new ImageAdapter(this));
gallery.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View v,
int position, long id) {
mSwitcher.setImageResource(mImageIds[position]);
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
}
public class ImageAdapter extends BaseAdapter {
private Context mContext;
public ImageAdapter(Context context) {
mContext = context;
}
public int getCount() {
return mThumbIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView image = new ImageView(mContext);
image.setImageResource(mThumbIds[position]);
image.setAdjustViewBounds(true);
image.setLayoutParams(new Gallery.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
return image;
}
}
private Integer[] mThumbIds = { R.drawable.icon01, R.drawable.icon02,
R.drawable.icon03, R.drawable.icon04, R.drawable.icon05 };
private Integer[] mImageIds = { R.drawable.icon01, R.drawable.icon02,
R.drawable.icon03, R.drawable.icon04, R.drawable.icon05 };
@Override
public View makeView() {
ImageView image = new ImageView(this);
image.setMinimumHeight(200);
image.setMinimumWidth(200);
image.setScaleType(ImageView.ScaleType.FIT_CENTER);
image.setLayoutParams(new ImageSwitcher.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
return image;
}
}
4、GridView 的 Demo
gridview.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<!--
GridView - 网格控件
numColumns="auto_fit" - 列数自适应
stretchMode - 缩放模式（stretchMode="columnWidth" - 缩放与列宽大小同步）
-->
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/gridView" android:layout_width="fill_parent"
android:layout_height="fill_parent" android:padding="10px"
android:verticalSpacing="10px" android:horizontalSpacing="10px"
android:numColumns="auto_fit" android:columnWidth="60px"
android:stretchMode="columnWidth" android:gravity="center">
</GridView>
_GridView.java
代码
package com.webabcd.view;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
public class _GridView extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.setContentView(R.layout.gridview);
setTitle("GridView");
GridView gridView = (GridView) findViewById(R.id.gridView);
// 指定网格控件的适配器为自定义的图片适配器
gridView.setAdapter(new ImageAdapter(this));
}
// 自定义的图片适配器
public class ImageAdapter extends BaseAdapter {
private Context mContext;
public ImageAdapter(Context context) {
mContext = context;
}
public int getCount() {
return mThumbIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView;
if (convertView == null) {
imageView = new ImageView(mContext);
imageView.setLayoutParams(new GridView.LayoutParams(48, 48));
imageView.setAdjustViewBounds(false);
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setPadding(5, 5, 5, 5);
} else {
imageView = (ImageView) convertView;
}
imageView.setImageResource(mThumbIds[position]);
return imageView;
}
// 网格控件所需图片数据的数据源
private Integer[] mThumbIds = { R.drawable.icon01, R.drawable.icon02,
R.drawable.icon03, R.drawable.icon04, R.drawable.icon05 };
}
}
5、ListView 的 Demo
main_list_adapter.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<!--
自定义列表适配器的 layout
-->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:id="@+id/text" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:textSize="16sp">
</TextView>
</LinearLayout>
MainListAdapter.java
代码
package com.webabcd.view;
import java.util.List;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
// 继承 BaseAdapter 以实现自定义的列表适配器
public class MainListAdapter extends BaseAdapter {
private LayoutInflater mInflater;
private List<String> mData;
public MainListAdapter(Context context, List<String> data) {
mInflater = LayoutInflater.from(context);
mData = data;
}
@Override
public int getCount() {
return mData.size();
}
@Override
public Object getItem(int position) {
return mData.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
TextView text;
if (convertView == null) {
// 指定一个 layout 作为自定义列表适配器的 layout
convertView = mInflater.inflate(R.layout.main_list_adapter, null);
text = (TextView) convertView.findViewById(R.id.text);
convertView.setTag(text);
} else {
text = (TextView) convertView.getTag();
}
String mItem = mData.get(position);
text.setText(mItem);
return convertView;
}
}
Main.java
代码
package com.webabcd.view;
import java.util.ArrayList;
import java.util.List;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ListView;
// 此处要继承 ListActivity ，用以实现 ListView 的功能
public class Main extends ListActivity {
private List<String> mData;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setTheme(android.R.style.Theme_Light);
setContentView(R.layout.main);
mData = getData();
// 使用自定义的列表适配器来展现数据
MainListAdapter adapter = new MainListAdapter(this, mData);
// 如需使用系统内置的列表适配器，则可以使用类似如下的方法
// ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1, mData);
this.setListAdapter(adapter);
}
// ListView 的数据源
private List<String> getData() {
List<String> items = new ArrayList<String>();
items.add("TextView");
items.add("Button");
items.add("ImageButton");
items.add("ImageView");
items.add("CheckBox");
items.add("RadioButton");
items.add("AnalogClock");
items.add("DigitalClock");
items.add("DatePicker");
items.add("TimePicker");
items.add("ToggleButton");
items.add("EditText");
items.add("ProgressBar");
items.add("SeekBar");
items.add("AutoCompleteTextView");
items.add("MultiAutoCompleteTextView");
items.add("ZoomControls");
items.add("Include");
items.add("VideoView");
items.add("WebView");
items.add("RatingBar");
items.add("Tab");
items.add("Spinner");
items.add("Chronometer");
items.add("ScrollView");
items.add("TextSwitcher");
items.add("ListView");
items.add("Gallery");
items.add("ImageSwitcher");
items.add("GridView");
items.add("ExpandableList");
return items;
}
// ListView 中某项被选中后的逻辑
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
Intent intent = new Intent();
intent.setClassName(this, "com.webabcd.view._" + mData.get(position));
startActivityForResult(intent, 0);
}
}
6、ExpandableList 的 Demo
_ExpandableList.java
代码
package com.webabcd.view;
import android.app.ExpandableListActivity;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.Gravity;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.AbsListView;
import android.widget.BaseExpandableListAdapter;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.ExpandableListView.ExpandableListContextMenuInfo;
// ExpandableList - 可展开/收缩列表
// 继承 ExpandableListActivity 以实现列表的可展开/收缩的功能
public class _ExpandableList extends ExpandableListActivity {
private ExpandableListAdapter mAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setTitle("ExpandableList");
mAdapter = new MyExpandableListAdapter();
setListAdapter(mAdapter);
registerForContextMenu(this.getExpandableListView());
}
// 为列表的每一项创建上下文菜单（即长按后呼出的菜单）
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
menu.setHeaderTitle("ContextMenu");
menu.add(0, 0, 0, "ContextMenu");
}
// 单击上下文菜单后的逻辑
@Override
public boolean onContextItemSelected(MenuItem item) {
ExpandableListContextMenuInfo info = (ExpandableListContextMenuInfo) item.getMenuInfo();
String title = ((TextView) info.targetView).getText().toString();
int type = ExpandableListView.getPackedPositionType(info.packedPosition);
if (type == ExpandableListView.PACKED_POSITION_TYPE_CHILD) {
int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition);
int childPos = ExpandableListView.getPackedPositionChild(info.packedPosition);
Toast.makeText(this, title + " - Group Index: " + groupPos + " Child Index: " + childPos, Toast.LENGTH_SHORT).show();
return true;
} else if (type == ExpandableListView.PACKED_POSITION_TYPE_GROUP) {
int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition);
Toast.makeText(this, title + " - Group Index: " + groupPos, Toast.LENGTH_SHORT).show();
return true;
}
return false;
}
public class MyExpandableListAdapter extends BaseExpandableListAdapter {
// 父列表数据
private String[] groups =
{
"group1",
"group2",
"group3",
"group4"
};
// 子列表数据
private String[][] children =
{
{ "child1" },
{ "child1", "child2" },
{ "child1", "child2", "child3" },
{ "child1", "child2", "child3", "child4" }
};
@Override
public Object getChild(int groupPosition, int childPosition) {
return children[groupPosition][childPosition];
}
@Override
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
@Override
public int getChildrenCount(int groupPosition) {
return children[groupPosition].length;
}
// 取子列表中的某一项的 View
@Override
public View getChildView(int groupPosition, int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
TextView textView = getGenericView();
textView.setText(getChild(groupPosition, childPosition).toString());
return textView;
}
@Override
public Object getGroup(int groupPosition) {
return groups[groupPosition];
}
@Override
public int getGroupCount() {
return groups.length;
}
@Override
public long getGroupId(int groupPosition) {
return groupPosition;
}
// 取父列表中的某一项的 View
@Override
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
TextView textView = getGenericView();
textView.setText(getGroup(groupPosition).toString());
return textView;
}
@Override
public boolean hasStableIds() {
return true;
}
@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
// 获取某一项的 View 的逻辑
private TextView getGenericView() {
AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT, 48);
TextView textView = new TextView(_ExpandableList.this);
textView.setLayoutParams(lp);
textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);
textView.setPadding(32, 0, 0, 0);
return textView;
}
}
}
Android(9) - 数据库支持(SQLite), 内容提供器(ContentProvider)
介绍
在 Android 中使用 SQLite, ContentProvider
· 数据库支持(SQLite) - Android 开发平台提供了操作 SQLite 数据库的相关 API
· 内容提供器(ContentProvider) - 当数据需要在应用程序之间共享时，可以在某程序中使用 ContentProvider 定义 URI， 以使其它应用程序可以通过此 URI 访问指定的数据
1、SQLite 的 Demo
DatabaseHelper.java
代码
package com.webabcd.SQLite;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
// 数据库操作的 Helper 类
public class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context, String name, CursorFactory cursorFactory, int version) {
super(context, name, cursorFactory, version);
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO 创建数据库后，对数据库的操作
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO 更改数据库版本的操作
}
@Override
public void onOpen(SQLiteDatabase db) {
super.onOpen(db);
// TODO 每次成功打开数据库后首先被执行
}
}
Main.java
代码
package com.webabcd.SQLite;
import java.util.Random;
import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class Main extends Activity {
private DatabaseHelper dbHelper;
private static final String DATABASE_NAME = "db.db";
private static final int DATABASE_VERSION = 1;
private static final String TABLE_NAME = "employee";
TextView txtMsg;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
dbHelper = new DatabaseHelper(this, DATABASE_NAME, null,
DATABASE_VERSION);
txtMsg = (TextView) this.findViewById(R.id.txtMsg);
Button btn1 = (Button) this.findViewById(R.id.btn1);
btn1.setText("创建表");
btn1.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
CreateTable();
}
});
Button btn2 = (Button) this.findViewById(R.id.btn2);
btn2.setText("插入 3 条记录");
btn2.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
insertItem();
}
});
Button btn3 = (Button) this.findViewById(R.id.btn3);
btn3.setText("删除全部记录");
btn3.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
deleteItem();
}
});
Button btn4 = (Button) this.findViewById(R.id.btn4);
btn4.setText("更新指定数据");
btn4.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
updateItem();
}
});
Button btn5 = (Button) this.findViewById(R.id.btn5);
btn5.setText("显示全部数据");
btn5.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
showItems();
}
});
Button btn6 = (Button) this.findViewById(R.id.btn6);
btn6.setText("删除表");
btn6.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
dropTable();
}
});
}
// 创建数据表
private void CreateTable() {
SQLiteDatabase db = dbHelper.getWritableDatabase();
String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME
+ " (ID INTEGER PRIMARY KEY, Name VARCHAR, Age INTEGER);";
try {
db.execSQL(sql);
txtMsg.append("数据表成功创建\n");
} catch (SQLException ex) {
txtMsg.append("数据表创建错误\n" + ex.toString() + "\n");
}
}
// 插入数据
private void insertItem() {
SQLiteDatabase db = dbHelper.getWritableDatabase();
try {
Random random = new Random();
for (int i = 0; i < 3; i++) {
String sql = "insert into " + TABLE_NAME
+ " (name, age) values ('name" + String.valueOf(i)
+ "', " + random.nextInt() + ")";
// execSQL() - 执行指定的 sql
db.execSQL(sql);
}
txtMsg.append("成功插入 3 条数据\n");
} catch (SQLException ex) {
txtMsg.append("插入数据失败\n" + ex.toString() + "\n");
}
}
// 删除数据
private void deleteItem() {
try {
SQLiteDatabase db = dbHelper.getWritableDatabase();
db.delete(TABLE_NAME, " id < 999999", null);
txtMsg.append("成功删除数据\n");
} catch (SQLException e) {
txtMsg.append("删除数据失败\n");
}
}
// 更新数据
private void updateItem() {
SQLiteDatabase db = dbHelper.getWritableDatabase();
try {
ContentValues values = new ContentValues();
values.put("name", "批量更新后的名字");
db.update(TABLE_NAME, values, "id<?", new String[] { "3" });
txtMsg.append("成功更新数据\n");
} catch (SQLException e) {
txtMsg.append("更新数据失败\n");
}
}
// 查询数据
private void showItems() {
SQLiteDatabase db = dbHelper.getReadableDatabase();
try {
String[] column = { "id", "name", "age" };
Cursor cursor = db.query(TABLE_NAME, column, null, null, null,
null, null);
Integer num = cursor.getCount();
txtMsg.append("共 " + Integer.toString(num) + " 条记录\n");
cursor.moveToFirst();
while (cursor.getPosition() != cursor.getCount()) {
txtMsg.append(Integer.toString(cursor.getPosition()) + ","
+ String.valueOf(cursor.getString(0)) + ","
+ cursor.getString(1) + ","
+ String.valueOf(cursor.getString(2)) + "\n");
cursor.moveToNext();
}
} catch (SQLException ex) {
txtMsg.append("读取数据失败\n" + ex.toString() + "\n");
}
}
// 删除数据表
private void dropTable() {
SQLiteDatabase db = dbHelper.getWritableDatabase();
String sql = "DROP TABLE IF EXISTS " + TABLE_NAME;
try {
db.execSQL(sql);
txtMsg.append("数据表删除成功\n");
} catch (SQLException ex) {
txtMsg.append("数据表删除错误\n" + ex.toString() + "\n");
}
}
}
2、ContentProvider 的 Demo
MyUser.java
代码
package com.webabcd.contentprovider;
import android.net.Uri;
import android.provider.BaseColumns;
// 自定义 ContentProvider 所需的实体类
public class MyUser {
// 必须要有 _id 字段。本例中 BaseColumn 类中已经包含了 _id 字段
public static final class User implements BaseColumns {
// 定义 CONTENT_URI
public static final Uri CONTENT_URI = Uri.parse("content://com.webabcd.MyContentProvider");
// 表数据列
public static final String USER_NAME = "USER_NAME";
}
}
MyContentProvider.java
代码
package com.webabcd.contentprovider;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import org.apache.http.util.EncodingUtils;
import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.MatrixCursor;
import android.net.Uri;
// 继承 ContentProvider 以实现自定义的 ContentProvider（基于文件的信息存储）
public class MyContentProvider extends ContentProvider {
private File file;
private FileOutputStream out;
private FileInputStream in;
// ContentProvider 的删除数据接口
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
// TODO Auto-generated method stub
return 0;
}
@Override
public String getType(Uri uri) {
// TODO Auto-generated method stub
return null;
}
// ContentProvider 的插入数据接口
@Override
public Uri insert(Uri uri, ContentValues values) {
try {
out = new FileOutputStream(file);
out.write(values.getAsString(MyUser.User.USER_NAME).getBytes());
out.close();
int rowId = 0;
Uri rowUri = ContentUris.appendId(
MyUser.User.CONTENT_URI.buildUpon(), rowId).build();
getContext().getContentResolver().notifyChange(rowUri, null);
return rowUri;
} catch (Exception e) {
return null;
}
}
// 创建用于保存信息的文件
@Override
public boolean onCreate() {
try {
// 每个包中应用程序的私有目录为：/data/data/包名/
// SD 卡目录为：/sdcard
file = new File("/data/data/com.webabcd.contentprovider/",
"demo.txt");
if (!file.exists())
file.createNewFile();
return true;
} catch (Exception ex) {
return false;
}
}
// ContentProvider 的查询数据接口
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
String content;
try {
in = new FileInputStream(file);
int length = (int) file.length();
byte[] buffer = new byte[length];
in.read(buffer, 0, length);
content = EncodingUtils.getString(buffer, "UTF-8");
in.close();
String[] columns = new String[] { MyUser.User._ID, MyUser.User.USER_NAME };
MatrixCursor cur = new MatrixCursor(columns);
String[] values = new String[] { "0", content };
cur.moveToFirst();
cur.addRow(values);
return cur;
} catch (Exception e) {
return null;
}
}
// ContentProvider 的更新数据接口
@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
// TODO Auto-generated method stub
return 0;
}
}
Main.java
代码
package com.webabcd.contentprovider;
import java.util.Random;
import android.app.Activity;
import android.content.ContentUris;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.Contacts;
import android.provider.Contacts.People;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
/*
* 几个常用的系统内置的 ContentProvider 如下：
* content://media/internal/images 这个URI将返回设备上存储的所有图片
* content://contacts/people/ 这个URI将返回设备上的所有联系人信息
* content://contacts/people/45 这个URI返回单个结果（联系人信息中ID为45的联系人记录）
*/
public class Main extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button btn1 = (Button) this.findViewById(R.id.btn1);
btn1.setText("新增联系人记录");
btn1.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
Random random = new Random();
insertRecords("name" + String.valueOf(random.nextInt()), String
.valueOf(random.nextInt()));
}
});
Button btn2 = (Button) this.findViewById(R.id.btn2);
btn2.setText("查看联系人记录");
btn2.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
displayRecords();
}
});
Button btn3 = (Button) this.findViewById(R.id.btn3);
btn3.setText("清除联系人记录");
btn3.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
deleteRecords();
}
});
Button btn4 = (Button) this.findViewById(R.id.btn4);
btn4.setText("更新联系人记录");
btn4.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
// 此处只是演示，id 来自 People._ID ，可参见 displayRecords() 是如何获取 id 的
int id = 0;
updateRecord(id, "修改后的name");
}
});
Button btn5 = (Button) this.findViewById(R.id.btn5);
btn5.setText("新增记录到 MyContentProvider");
btn5.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
insertRecord2MyContentProvider("webabcd");
}
});
Button btn6 = (Button) this.findViewById(R.id.btn6);
btn6.setText("获取记录从 MyContentProvider");
btn6.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
displayRecord2MyContentProvider();
}
});
}
// 调用 ContentProvider 的插入接口
private void insertRecords(String name, String phoneNum) {
ContentValues values = new ContentValues();
values.put(People.NAME, name);
Uri uri = getContentResolver().insert(People.CONTENT_URI, values);
Log.d("MyDebug", uri.toString());
Uri numberUri = Uri.withAppendedPath(uri,
People.Phones.CONTENT_DIRECTORY);
Log.d("MyDebug", numberUri.toString());
values.clear();
values.put(Contacts.Phones.TYPE, People.Phones.TYPE_MOBILE);
values.put(People.NUMBER, phoneNum);
getContentResolver().insert(numberUri, values);
}
// 调用 ContentProvider 的查询接口
private void displayRecords() {
String[] columns = new String[] { People._ID, People.NAME,
People.NUMBER };
Uri contacts = People.CONTENT_URI;
Log.d("MyDebug", contacts.toString());
Cursor cur = managedQuery(contacts, columns, // 要返回的数据字段
null, // WHERE子句
null, // WHERE 子句的参数
null // Order-by子句
);
if (cur.moveToFirst()) {
String id = null;
String name = null;
String phoneNo = null;
while (cur.getPosition() != cur.getCount()) {
id = cur.getString(cur.getColumnIndex(People._ID));
name = cur.getString(cur.getColumnIndex(People.NAME));
phoneNo = cur.getString(cur.getColumnIndex(People.NUMBER));
Toast.makeText(this, id + " / " + name + " / " + phoneNo,
Toast.LENGTH_SHORT).show();
cur.moveToNext();
}
}
}
// 调用 ContentProvider 的删除接口
private void deleteRecords() {
Uri uri = People.CONTENT_URI;
Log.d("MyDebug", uri.toString());
getContentResolver().delete(uri, null, null);
// getContentResolver().delete(uri, "NAME=" + "'name'", null);
}
// 调用 ContentProvider 的更新接口
private void updateRecord(int recordNo, String name) {
Uri uri = ContentUris.withAppendedId(People.CONTENT_URI, recordNo);
Log.d("MyDebug", uri.toString());
ContentValues values = new ContentValues();
values.put(People.NAME, name);
getContentResolver().update(uri, values, null, null);
}
// 调用自定义 ContentProvider 的插入接口
private void insertRecord2MyContentProvider(String name) {
ContentValues values = new ContentValues();
values.put(MyUser.User.USER_NAME, name);
getContentResolver().insert(MyUser.User.CONTENT_URI, values);
}
// 调用自定义 ContentProvider 的查询接口
private void displayRecord2MyContentProvider() {
String[] columns = new String[] { MyUser.User.USER_NAME };
Uri uri = MyUser.User.CONTENT_URI;
Cursor cur = managedQuery(uri, columns, null, null, null);
while (cur.getPosition() != cur.getCount()) {
String id = cur.getString(cur.getColumnIndex(People._ID));
String name = cur.getString(cur.getColumnIndex(MyUser.User.USER_NAME));
Toast.makeText(this,
id + " / " + name,
Toast.LENGTH_SHORT).show();
cur.moveToNext();
}
}
}
AndroidManifest.xml
代码
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.webabcd.contentprovider"
android:versionCode="1"
android:versionName="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".Main"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<!--
配置一个自定义的 ContentProvider"
-->
<provider android:name="MyContentProvider" android:authorities="com.webabcd.MyContentProvider" />
</application>
<uses-permission android:name="android.permission.WRITE_CONTACTS"></uses-permission>
<uses-permission android:name="android.permission.READ_CONTACTS"></uses-permission>
<uses-sdk android:minSdkVersion="3" />
</manifest>
Android(10) - HTTP 通信, XML 解析, 通过 Hander 实现异步消息处理
介绍
在 Android 中与服务端做 HTTP 通信，解析 XML，通过 Handler 实现异步消息处理
· HTTP 通信 - 与服务端做 HTTP 通信，分别以 GET 方式和 POST 方式做演示
· XML 解析 - 可以用两种方式解析 XML，分别是 DOM 方式和 SAX 方式
· 异步消息处理 - 通过 Handler 实现异步消息处理，以一个自定义的异步下载类来说明 Handler 的用法
1、HTTP 通信和 XML 解析的 Demo
MySAXHandler.java
代码
package com.webabcd.communication;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
// 继承 DefaultHandler 以实现指定 XML 的 SAX 解析器
// DOM - W3C 标准，需要把 xml 数据全部加载完成后才能对其做解析，可对树做任意遍历
// SAX - 流式解析，通过事件模型解析 xml，只能顺序解析
public class MySAXHandler extends DefaultHandler {
private boolean mIsTitleTag = false;
private boolean mIsSalaryTag = false;
private boolean mIsBirthTag = false;
private String mResult = "";
// 打开 xml 文档的回调函数
@Override
public void startDocument() throws SAXException {
// TODO Auto-generated method stub
super.startDocument();
}
// 关闭 xml 文档的回调函数
@Override
public void endDocument() throws SAXException {
// TODO Auto-generated method stub
super.endDocument();
}
// 一发现元素开始标记就回调此函数
@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
if (localName == "title")
mIsTitleTag = true;
else if (localName == "salary")
mIsSalaryTag = true;
else if (localName == "dateOfBirth")
mIsBirthTag = true;
else if (localName == "employee")
mResult += "\nname:" + attributes.getValue("name");
}
// 一发现元素结束标记就回调此函数
@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
if (localName == "title")
mIsTitleTag = false;
else if (localName == "salary")
mIsSalaryTag = false;
else if (localName == "dateOfBirth")
mIsBirthTag = false;
}
// 一发现元素值或属性值就回调此函数
@Override
public void characters(char[] ch, int start, int length)
throws SAXException {
if (mIsTitleTag)
mResult += new String(ch, start, length);
else if (mIsSalaryTag)
mResult += " salary:" + new String(ch, start, length);
else if (mIsBirthTag)
mResult += " dateOfBirth:" + new String(ch, start, length);
}
public String getResult(){
return mResult;
}
}
Main.java
代码
package com.webabcd.communication;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.ByteArrayBuffer;
import org.apache.http.util.EncodingUtils;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class Main extends Activity {
private TextView textView;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
textView = (TextView) this.findViewById(R.id.textView);
Button btn1 = (Button) this.findViewById(R.id.btn1);
btn1.setText("http get demo");
btn1.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
httpGetDemo();
}
});
Button btn2 = (Button) this.findViewById(R.id.btn2);
btn2.setText("http post demo");
btn2.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
httpPostDemo();
}
});
Button btn3 = (Button) this.findViewById(R.id.btn3);
// DOM - Document Object Model
btn3.setText("DOM 解析 XML");
btn3.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
DOMDemo();
}
});
Button btn4 = (Button) this.findViewById(R.id.btn4);
// SAX - Simple API for XML
btn4.setText("SAX 解析 XML");
btn4.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
SAXDemo();
}
});
}
// Android 调用 http 协议的 get 方法
// 本例：以 http 协议的 get 方法获取远程页面响应的内容
private void httpGetDemo(){
try {
// 模拟器测试时，请使用外网地址
URL url = new URL("http://xxx.xxx.xxx");
URLConnection con = url.openConnection();
String result = "http status code: " + ((HttpURLConnection)con).getResponseCode() + "\n";
// HttpURLConnection.HTTP_OK
InputStream is = con.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);
ByteArrayBuffer bab = new ByteArrayBuffer(32);
int current = 0;
while ( (current = bis.read()) != -1 ){
bab.append((byte)current);
}
result += EncodingUtils.getString(bab.toByteArray(), HTTP.UTF_8);
bis.close();
is.close();
textView.setText(result);
} catch (Exception e) {
textView.setText(e.toString());
}
}
// Android 调用 http 协议的 post 方法
// 本例：以 http 协议的 post 方法向远程页面传递参数，并获取其响应的内容
private void httpPostDemo(){
try {
// 模拟器测试时，请使用外网地址
String url = "http://5billion.com.cn/post.php";
Map<String, String> data = new HashMap<String, String>();
data.put("name", "webabcd");
data.put("salary", "100");
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
ArrayList<BasicNameValuePair> postData = new ArrayList<BasicNameValuePair>();
for (Map.Entry<String, String> m : data.entrySet()) {
postData.add(new BasicNameValuePair(m.getKey(), m.getValue()));
}
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(postData, HTTP.UTF_8);
httpPost.setEntity(entity);
HttpResponse response = httpClient.execute(httpPost);
String result = "http status code: " + response.getStatusLine().getStatusCode() + "\n";
// HttpURLConnection.HTTP_OK
HttpEntity httpEntity = response.getEntity();
InputStream is = httpEntity.getContent();
result += convertStreamToString(is);
textView.setText(result);
} catch (Exception e) {
textView.setText(e.toString());
}
}
// 以 DOM 方式解析 XML（xml 数据详见 res/raw/employee.xml）
private void DOMDemo(){
try {
DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
Document doc = docBuilder.parse(this.getResources().openRawResource(R.raw.employee));
Element rootElement = doc.getDocumentElement();
NodeList employeeNodeList = rootElement.getElementsByTagName("employee");
textView.setText("DOMDemo" + "\n");
String title = rootElement.getElementsByTagName("title").item(0).getFirstChild().getNodeValue();
textView.append(title);
for (int i=0; i<employeeNodeList.getLength(); i++){
Element employeeElement = ((Element)employeeNodeList.item(i));
String name = employeeElement.getAttribute("name");
String salary = employeeElement.getElementsByTagName("salary").item(0).getFirstChild().getNodeValue();
String dateOfBirth = employeeElement.getElementsByTagName("dateOfBirth").item(0).getFirstChild().getNodeValue();
textView.append("\nname: "+name+" salary: "+salary+" dateOfBirth: " + dateOfBirth);
}
} catch (Exception e) {
textView.setText(e.toString());
}
}
// 以 SAX 方式解析 XML（xml 数据详见 res/raw/employee.xml）
// SAX 解析器的实现详见 MySAXHandler.java
private void SAXDemo(){
try {
SAXParserFactory saxFactory = SAXParserFactory.newInstance();
SAXParser parser = saxFactory.newSAXParser();
XMLReader reader = parser.getXMLReader();
MySAXHandler handler = new MySAXHandler();
reader.setContentHandler(handler);
reader.parse(new InputSource(this.getResources().openRawResource(R.raw.employee)));
String result = handler.getResult();
textView.setText("SAXDemo" + "\n");
textView.append(result);
} catch (Exception e) {
textView.setText(e.toString());
}
}
// 辅助方法，用于把流转换为字符串
private String convertStreamToString(InputStream is) {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
}
2、用 Handler 来实现异步消息处理，以一个可以实时汇报下载进度的异步下载类为例
开发一个 Android 类库，本例中此类库名为 webabcd_util
New -> Java Project
项目上点右键 -> Build Path -> Add Libraries -> User Library -> User Libraries -> New -> 为类库起个名字 -> 选中这个类库 -> Add JARs 导入 Android 的 jar 包
项目上点右键 -> Build Path -> Add Libraries -> User Library -> 选择 Android 库
DownloadManagerAsync.java
代码
package webabcd.util;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import org.apache.http.protocol.HTTP;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
// 以一个实例，即异步下载，来演示 Android 的异步消息处理（用 Handler 的方式）
public class DownloadManagerAsync {
public DownloadManagerAsync() {
}
// 实例化自定义的 Handler
EventHandler mHandler = new EventHandler(this);
// 按指定 url 地址下载文件到指定路径
public void download(final String url, final String savePath) {
new Thread(new Runnable() {
public void run() {
try {
sendMessage(FILE_DOWNLOAD_CONNECT);
URL sourceUrl = new URL(url);
URLConnection conn = sourceUrl.openConnection();
InputStream inputStream = conn.getInputStream();
int fileSize = conn.getContentLength();
File savefile = new File(savePath);
if (savefile.exists()) {
savefile.delete();
}
savefile.createNewFile();
FileOutputStream outputStream = new FileOutputStream(
savePath, true);
byte[] buffer = new byte[1024];
int readCount = 0;
int readNum = 0;
int prevPercent = 0;
while (readCount < fileSize && readNum != -1) {
readNum = inputStream.read(buffer);
if (readNum > -1) {
outputStream.write(buffer);
readCount = readCount + readNum;
int percent = (int) (readCount * 100 / fileSize);
if (percent > prevPercent) {
// 发送下载进度信息
sendMessage(FILE_DOWNLOAD_UPDATE, percent,
readCount);
prevPercent = percent;
}
}
}
outputStream.close();
sendMessage(FILE_DOWNLOAD_COMPLETE, savePath);
} catch (Exception e) {
sendMessage(FILE_DOWNLOAD_ERROR, e);
Log.e("MyError", e.toString());
}
}
}).start();
}
// 读取指定 url 地址的响应内容
public void download(final String url) {
new Thread(new Runnable() {
public void run() {
try {
sendMessage(FILE_DOWNLOAD_CONNECT);
URL sourceUrl = new URL(url);
URLConnection conn = sourceUrl.openConnection();
conn.setConnectTimeout(3000);
BufferedReader reader = new BufferedReader(
new InputStreamReader(conn.getInputStream(),
HTTP.UTF_8));
String line = null;
StringBuffer content = new StringBuffer();
while ((line = reader.readLine()) != null) {
content.append(line);
}
reader.close();
sendMessage(FILE_DOWNLOAD_COMPLETE, content.toString());
} catch (Exception e) {
sendMessage(FILE_DOWNLOAD_ERROR, e);
Log.e("MyError", e.toString());
}
}
}).start();
}
// 向 Handler 发送消息
private void sendMessage(int what, Object obj) {
// 构造需要向 Handler 发送的消息
Message msg = mHandler.obtainMessage(what, obj);
// 发送消息
mHandler.sendMessage(msg);
}
private void sendMessage(int what) {
Message msg = mHandler.obtainMessage(what);
mHandler.sendMessage(msg);
}
private void sendMessage(int what, int arg1, int arg2) {
Message msg = mHandler.obtainMessage(what, arg1, arg2);
mHandler.sendMessage(msg);
}
private static final int FILE_DOWNLOAD_CONNECT = 0;
private static final int FILE_DOWNLOAD_UPDATE = 1;
private static final int FILE_DOWNLOAD_COMPLETE = 2;
private static final int FILE_DOWNLOAD_ERROR = -1;
// 自定义的 Handler
private class EventHandler extends Handler {
private DownloadManagerAsync mManager;
public EventHandler(DownloadManagerAsync manager) {
mManager = manager;
}
// 处理接收到的消息
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case FILE_DOWNLOAD_CONNECT:
if (mOnDownloadConnectListener != null)
mOnDownloadConnectListener.onDownloadConnect(mManager);
break;
case FILE_DOWNLOAD_UPDATE:
if (mOnDownloadUpdateListener != null)
mOnDownloadUpdateListener.onDownloadUpdate(mManager,
msg.arg1);
break;
case FILE_DOWNLOAD_COMPLETE:
if (mOnDownloadCompleteListener != null)
mOnDownloadCompleteListener.onDownloadComplete(mManager,
msg.obj);
break;
case FILE_DOWNLOAD_ERROR:
if (mOnDownloadErrorListener != null)
mOnDownloadErrorListener.onDownloadError(mManager,
(Exception) msg.obj);
break;
default:
break;
}
}
}
// 定义连接事件
private OnDownloadConnectListener mOnDownloadConnectListener;
public interface OnDownloadConnectListener {
void onDownloadConnect(DownloadManagerAsync manager);
}
public void setOnDownloadConnectListener(OnDownloadConnectListener listener) {
mOnDownloadConnectListener = listener;
}
// 定义下载进度更新事件
private OnDownloadUpdateListener mOnDownloadUpdateListener;
public interface OnDownloadUpdateListener {
void onDownloadUpdate(DownloadManagerAsync manager, int percent);
}
public void setOnDownloadUpdateListener(OnDownloadUpdateListener listener) {
mOnDownloadUpdateListener = listener;
}
// 定义下载完成事件
private OnDownloadCompleteListener mOnDownloadCompleteListener;
public interface OnDownloadCompleteListener {
void onDownloadComplete(DownloadManagerAsync manager, Object result);
}
public void setOnDownloadCompleteListener(
OnDownloadCompleteListener listener) {
mOnDownloadCompleteListener = listener;
}
// 定义下载异常事件
private OnDownloadErrorListener mOnDownloadErrorListener;
public interface OnDownloadErrorListener {
void onDownloadError(DownloadManagerAsync manager, Exception e);
}
public void setOnDownloadErrorListener(OnDownloadErrorListener listener) {
mOnDownloadErrorListener = listener;
}
}
调用上面的自定义的 Android 类库
项目上点右键 -> Properties -> Java Build Path -> Projects -> Add 引用上面的类库
Main.java
代码
package com.webabcd.handler;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import webabcd.util.DownloadManagerAsync;
public class Main extends Activity implements
DownloadManagerAsync.OnDownloadCompleteListener,
DownloadManagerAsync.OnDownloadUpdateListener,
DownloadManagerAsync.OnDownloadErrorListener {
TextView txt;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
DownloadManagerAsync manager = new DownloadManagerAsync();
manager.setOnDownloadCompleteListener(this);
manager.setOnDownloadUpdateListener(this);
manager.download("http://files.cnblogs.com/webabcd/Android.rar", "/sdcard/Android.rar");
txt = (TextView) this.findViewById(R.id.txt);
txt.setText("开始下载");
}
public void onDownloadComplete(DownloadManagerAsync manager, Object result) {
txt.setText("下载完成");
}
public void onDownloadUpdate(DownloadManagerAsync manager, int percent) {
txt.setText("下载进度：" + String.valueOf(percent) + "%");
}
public void onDownloadError(DownloadManagerAsync manager, Exception e) {
txt.setText("下载出错");
}
}
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