Android学习笔记之四

基本视图介绍

1.文本 按钮与输入框

文本 按钮 输入框的继承关系

TextView:
android:text=”文本”
android:textSize=”20sp”
android:textColor=”#FF0”
android:textStyle=”bold”
android:lines=”3”
android:singleLine=”true”
android:typeface=”monospace” //设置字型。字形有：normal, sans, serif,monospace
android:clickable=””

Button:
属性与TextView基本相似。
不同点：
1. 按钮是自带了背景的控件
2. 按钮是可以点击了

EditText：
android:hint=”请输入QQ”
android:editable=”true”
android:maxLength=”50” 设置最大的字数
android:inputType=”textPassword”

2.是非选择框

ToggleButton：
android:textOn=”开启”
android:textOff=”关闭”
android:checked=”true”

RadioButton(单选框)：
RadioGroup 单选组
RadioButton 单选框
一般它们是配合使用的
设置监听器的时候,通过 RadioGroup radioGroup.setOnCheckedChangeListener();
android:checked=”true”

CheckBox：
设置监听器的时候 每个CheckBox都应该设置
android:checked=”false”

附 ToggleButton和CheckBox练习代码:

MainActivity.javapackage com.m520it.select;import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.widget.CheckBox;import android.widget.CompoundButton;import android.widget.CompoundButton.OnCheckedChangeListener;import android.widget.RadioButton;import android.widget.RadioGroup;import android.widget.Toast;public class MainActivity extends Activity{    private List<String> mChooseData = new ArrayList<String>();    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        CheckBox aCbx = (CheckBox) findViewById(R.id.cbx_apple);        CheckBox bCbx = (CheckBox) findViewById(R.id.cbx_banance);        CheckBox cCbx = (CheckBox) findViewById(R.id.cbx_orange);        myCheckedChangeListener listener = new myCheckedChangeListener();        aCbx.setOnCheckedChangeListener(listener);        bCbx.setOnCheckedChangeListener(listener);    }    class myCheckedChangeListener implements OnCheckedChangeListener{        @Override        public void onCheckedChanged(CompoundButton buttonView,                boolean isChecked) {            int CbxId = buttonView.getId();            if(CbxId==R.id.cbx_apple){                if(isChecked){                    mChooseData.add("苹果");                }else{                    if(mChooseData.contains("苹果")){                        mChooseData.remove("苹果");                    }                }            }else if(CbxId==R.id.cbx_banance){                if(isChecked){                    mChooseData.add("香蕉");                }else{                    if(mChooseData.contains("香蕉")){                        mChooseData.remove("香蕉");                    }                }            }else if(CbxId==R.id.cbx_orange){                if(isChecked){                    mChooseData.add("橘子");                }else{                    if(mChooseData.contains("橘子")){                        mChooseData.remove("橘子");                    }                }            }        }    }    public void myClick(View v){        String result = "";        for (int i = 0; i < mChooseData.size(); i++) {            result+=mChooseData.get(i);        }        Toast.makeText(this, result, Toast.LENGTH_SHORT).show();    }}布局文件activity_main.xml:<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >    <ToggleButton        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:checked="true"        android:textOff="关"        android:textOn="开" />    <CheckBox        android:id="@+id/cbx_apple"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="苹果" />    <CheckBox        android:id="@+id/cbx_banance"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="香蕉" />    <CheckBox        android:id="@+id/cbx_orange"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="橘子" />    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:onClick="myClick"        android:text="button" /></LinearLayout>

附 RadioGroup和RadioButton练习代码:

MainActivity.javapackage com.m520it.select;import android.app.Activity;import android.os.Bundle;import android.widget.RadioButton;import android.widget.RadioGroup;import android.widget.RadioGroup.OnCheckedChangeListener;import android.widget.Toast;public class MainActivity extends Activity implements OnCheckedChangeListener {    private RadioButton mARg;    private RadioButton mBRg;    private RadioButton mCRg;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.radiogroup);        radioEvent();    }    @Override    public void onCheckedChanged(RadioGroup group, int checkedId) {        if (R.id.rg_a == checkedId) {            Toast.makeText(this, mARg.getText().toString(), Toast.LENGTH_SHORT)                    .show();        } else if (R.id.rg_b == checkedId) {            Toast.makeText(this, mBRg.getText().toString(), Toast.LENGTH_SHORT)                    .show();        } else if (R.id.rg_c == checkedId) {            Toast.makeText(this, mCRg.getText().toString(), Toast.LENGTH_SHORT)                    .show();        }    }    public void radioEvent() {        RadioGroup rg = (RadioGroup) findViewById(R.id.rg);        mARg = (RadioButton) findViewById(R.id.rg_a);        mBRg = (RadioButton) findViewById(R.id.rg_b);        mCRg = (RadioButton) findViewById(R.id.rg_c);        rg.setOnCheckedChangeListener(this);    }}布局文件R.layout.radiogroup:<?xml version="1.0" encoding="utf-8"?><RadioGroup xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"     android:id="@+id/rg"    >    <RadioButton        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="苹果"         android:id="@+id/rg_a"        />    <RadioButton        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="香蕉"        android:id="@+id/rg_b"          />    <RadioButton        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="西瓜"          android:id="@+id/rg_c"        /></RadioGroup>

3.进度条

没有进度的进度条

• 大进度条
  style=”?android:attr/progressBarStyleLarge”
• 普通进度条
  style=”?android:attr/progressBarStyle”
• 小进度条
  style=”?android:attr/progressBarStyleSmall”

有进度的进度条

style=”?android:attr/progressBarStyleHorizontal”
android:progress=”80”
android:max=”100”

3.可拖动的进度条

SeekBar：可拖动的进度条
android:max=”100”
android:progress=”50”

4.星星进度条

RatingBar：星星进度条 基本单位为半颗星
android:numStars=”4”
android:rating=”3.5”
android:stepSize=”0.5”

练习代码:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >    <!-- 没有进度的进度条 -->    <ProgressBar        style="?android:attr/progressBarStyleLarge"        android:layout_width="wrap_content"        android:layout_height="wrap_content" />    <ProgressBar        style="?android:attr/progressBarStyle"        android:layout_width="wrap_content"        android:layout_height="wrap_content" />    <ProgressBar        style="?android:attr/progressBarStyleSmall"        android:layout_width="wrap_content"        android:layout_height="wrap_content" />    <!-- 有进度的进度条 -->    <ProgressBar        style="?android:attr/progressBarStyleHorizontal"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_marginTop="10dp"        android:max="100"        android:progress="80" />    <!-- 可以拖动的进度条 -->    <SeekBar        android:layout_width="match_parent"        android:layout_height="wrap_content"         android:max="100"        android:progress="40"        />    <!--星星进度条  -->    <RatingBar         android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:numStars="4"        android:rating="3.5"        android:stepSize="0.5"        /></LinearLayout>

3.图片控件(ImageView)

设置图片源
android:src=”@drawable/ic_launcher”

代码设置图片源
imageView.setImageResource(resId)
imageView.setImageBitmap(bm);
imageView.setImageDrawable(drawable);

设置缩放模式
android:scaleType=”“

练习demo:

MainActivity.javapackage com.m520it.imageView;import android.app.Activity;import android.os.Bundle;import android.widget.ImageView;public class MainActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        ImageView imageView = (ImageView) findViewById(R.id.iv2);        /*imageView.setImageResource(resId)        imageView.setImageBitmap(bm);        imageView.setImageDrawable(drawable);*/        imageView.setImageResource(R.drawable.flower);    }}布局文件activity_main.xml<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    >    <ImageView        android:id="@+id/iv1"        android:layout_width="150dp"        android:layout_height="150dp"        android:scaleType="centerCrop"        android:src="@drawable/flower" />    <ImageView         android:id="@+id/iv2"        android:layout_width="150dp"        android:layout_height="150dp"        /></LinearLayout>

4.滑动控件

1. 手机界面无法容纳更多的控件的时候，就需要滚动界面。
2. ScrollView :控制上下滑动的效果
3. HorizontalScrollView: 控制左右滑动的效果
4. ScrollView与HorizontalScrollView只能容纳一个子控件。

HorizontalScrollView的布局demo<?xml version="1.0" encoding="utf-8"?><HorizontalScrollView xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent" >    <LinearLayout        android:layout_width="match_parent"        android:layout_height="match_parent"        android:orientation="vertical" >        <TextView            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!"            android:textSize="30sp" />        <TextView            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="Hello world!Hello world!Hello world!Hello world!Hello world!Hello world!"            android:textColor="#F00"            android:textSize="30sp" />    </LinearLayout></HorizontalScrollView>ScrollView的布局demo<?xml version="1.0" encoding="utf-8"?><ScrollView xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent" >    <LinearLayout        android:layout_width="match_parent"        android:layout_height="match_parent"        android:orientation="vertical" >         <TextView            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="Hello world"            android:lines="10"            android:textSize="30sp" />        <TextView            android:text="Hello world"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:textColor="#F00"            android:lines="10"            android:textSize="30sp" />        <TextView            android:text="Hello world"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:textColor="#F00"            android:lines="10"            android:textSize="30sp" />    </LinearLayout></ScrollView>

5.日期时间选择器

直接敲一个demo就理解了

MainActivity.javapackage com.m520it.dateAndTime;import java.util.Calendar;import java.util.Locale;import android.app.Activity;import android.os.Bundle;import android.widget.DatePicker;import android.widget.DatePicker.OnDateChangedListener;import android.widget.TimePicker;import android.widget.TimePicker.OnTimeChangedListener;import android.widget.Toast;public class MainActivity extends Activity implements OnDateChangedListener {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //获取日期控件        DatePicker datePicker = (DatePicker) findViewById(R.id.datePicker);        Calendar calendar = Calendar.getInstance(Locale.CHINESE);        int year = calendar.get(Calendar.YEAR);        int month = calendar.get(Calendar.MONTH);        int day = calendar.get(Calendar.DAY_OF_MONTH);        //init用来初始化改变后的日期        //this 日期改变的监听器        datePicker.init(year, month, day,this);        //获取时间控件        TimePicker timePicker = (TimePicker) findViewById(R.id.timePicker);        //设置24小时        timePicker.setIs24HourView(true);        //设置监听器        timePicker.setOnTimeChangedListener(new OnTimeChangedListener() {            @Override            public void onTimeChanged(TimePicker view, int hourOfDay, int minute) {                System.out.println(hourOfDay+"..."+minute);                Toast.makeText(MainActivity.this,hourOfDay+"..."+minute,Toast.LENGTH_SHORT).show();            }        });    }    @Override    public void onDateChanged(DatePicker view, int year, int monthOfYear,            int dayOfMonth) {        Toast.makeText(this,"year:"+year+" mothOfYear:"+(monthOfYear+1)+" dayOfMonth:"+dayOfMonth, Toast.LENGTH_SHORT).show();    }}布局文件activity_main.xml:<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.m520it.dateAndTime.MainActivity"     android:orientation="vertical"    >    <DatePicker        android:id="@+id/datePicker"        android:layout_width="wrap_content"        android:layout_height="wrap_content"      />    <TimePicker         android:id="@+id/timePicker"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        /></LinearLayout>