android 学习随笔二十八（应用小知识点小结）

来源：互联网发布：重做系统数据恢复编辑：程序博客网时间：2024/05/04 19:16

去掉标题栏的方法

第一种：也一般入门的时候经常使用的一种方法
requestWindowFeature(Window.FEATURE_NO_TITLE);//去掉标题栏
注意这句一定要写在setContentView()方法的前面，不然会报错的

第二种：在AndroidManifest.xml文件中定义
<application android:icon="@drawable/icon"
android:label="@string/app_name"
android:theme="@android:style/Theme.NoTitleBar">
可以看出，这样写的话，整个应用都会去掉标题栏，如果只想去掉某一个Activity的标题栏的话，可以把这个属性加到activity标签里面

注：这种方法在android4.1.1的三星i9300手机上TabHost中不起作用，需要采用第一种方式加上setTheme一起控制。
setTheme(android.R.style.Theme_Black_NoTitleBar);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.api_tab_host);

第三种：自定义样式，在一般的应用中不常用，在res/values目录下面新建一个style.xml的文件
例如：
<?xml version="1.0" encoding="UTF-8" ?>
<resources>
<style name="notitle">
<item name="android:windowNoTitle">true</item>
</style>
</resources>
相当于一个主题，然后在AndroidManifest.xml文件中定义

<application android:icon="@drawable/icon"
android:label="@string/app_name"
android:theme="@style/notitle">
达到去掉标题栏的效果

第一种有的时候我们会看到，会先出现标题栏，然后再消失，因为是在activity的oncreate方法中定义的。
第二种相对第一种比较好一些，不会出现这种情况。
第三种可以把功能分开，便于维护和扩展，但比较麻烦。

------------------------------------------------------

全屏的方法

第一种
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);

第二种
android:theme="@android:style/Theme.NoTitleBar.Fullscreen"

第三种
application android:icon="@drawable/icon"
android:label="@string/app_name"
android:theme="@style/fullscreem"

ListView自动滑动

public void initView() {
setContentView(R.layout.activity_conversation_detail);

lv_conversation_detail = (ListView) findViewById(R.id.lv_conversation_detail);
et_conversation_detail = (EditText) findViewById(R.id.et_conversation_detail);
bt_conversation_detail_send = (Button) findViewById(R.id.bt_conversation_detail_send);

//只要ListView刷新，就会滑动
lv_conversation_detail.setTranscriptMode(AbsListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
}

发送短信与接收发送结果

package com.itheima.momo.dao;import java.util.List;import com.itheima.momo.globle.Constant;import com.itheima.momo.receiver.SendSmsReceiver;import android.app.PendingIntent;import android.content.ContentValues;import android.content.Context;import android.content.Intent;import android.telephony.SmsManager;public class SmsDao {    public static void sendSms(Context context, String address, String body){        SmsManager manager = SmsManager.getDefault();        List<String> smss = manager.divideMessage(body);                Intent intent = new Intent(SendSmsReceiver.ACTION_SEND_SMS);        //短信发出去后，系统会发送一条广播，告知我们短信发送是成功还是失败        PendingIntent sentIntent = PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_ONE_SHOT);        for (String text : smss) {            //这个api只负责发短信，不会把短信写入数据库            manager.sendTextMessage(address, null, text, sentIntent, null);                    //把短信插入短信数据库            insertSms(context, address, text);        }    }        public static void insertSms(Context context, String address, String body){        //只要插入address就可以了，thread_id不需要插入，这个会自动识别的。         ContentValues values = new ContentValues();        values.put("address", address);        values.put("body", body);        values.put("type", Constant.SMS.TYPE_SEND);                context.getContentResolver().insert(Constant.URI.URI_SMS, values);    }}

View Code

package com.itheima.momo.receiver;import com.itheima.momo.utils.ToastUtils;import android.app.Activity;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;public class SendSmsReceiver extends BroadcastReceiver {        public static final String ACTION_SEND_SMS = "com.itheima.momo.sendsms";    @Override    public void onReceive(Context context, Intent intent) {        int code = getResultCode();        if(code == Activity.RESULT_OK ){            ToastUtils.ShowToast(context, "发送成功");        }        else{            ToastUtils.ShowToast(context, "发送失败");        }    }}

View Code

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.itheima.momo"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="8"        android:targetSdkVersion="17" />    <uses-permission android:name="android.permission.READ_SMS"/>    <uses-permission android:name="android.permission.READ_CONTACTS"/>    <uses-permission android:name="android.permission.WRITE_SMS"/>    <uses-permission android:name="android.permission.SEND_SMS"/>    <application        android:allowBackup="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity            android:name="com.itheima.momo.ui.activity.MainActivity"            android:label="@string/app_name" >            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>                <activity android:name="com.itheima.momo.ui.activity.ConversationDetailActivity"            android:windowSoftInputMode="stateUnspecified|adjustResize"            ></activity>                <activity android:name="com.itheima.momo.ui.activity.NewMsgActivity"></activity>                <receiver android:name="com.itheima.momo.receiver.SendSmsReceiver">            <intent-filter >                <action android:name="com.itheima.momo.sendsms"/>            </intent-filter>        </receiver>                <provider android:name="com.itheima.momo.provider.GroupProvider"            android:exported="true"            android:authorities="com.itheima.momo"            ></provider>    </application></manifest>

View Code

利用接口定义常量

public class Constant {

public interface URI{
Uri URI_SMS_CONVERSATION = Uri.parse("content://sms/conversations");
Uri URI_SMS = Uri.parse("content://sms");
Uri URI_GROUP_INSERT = Uri.parse("content://com.itheima.momo/groups/insert");
}
public interface SMS{
int TYPE_RECEIVE = 1;
int TYPE_SEND = 2;
}
}

创建数据库

package com.itheima.momo.dao;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;public class GroupOpenHelper extends SQLiteOpenHelper {    //单例模式获取GroupOpenHelper实例    private static GroupOpenHelper instance;        public static GroupOpenHelper getInstance(Context context){        if(instance == null){            instance = new GroupOpenHelper(context, "group.db", null, 1);        }        return instance;    }        private GroupOpenHelper(Context context, String name, CursorFactory factory,            int version) {        super(context, name, factory, version);        // TODO Auto-generated constructor stub    }    @Override    public void onCreate(SQLiteDatabase db) {        //创建groups表        db.execSQL("create table groups(" +                "_id integer primary key autoincrement, " +                "name varchar, " +                "create_date integer, " +                "thread_count integer" +                 ")");        //创建会话和群组的映射表        db.execSQL("create table thread_group(" +                "_id integer primary key autoincrement, " +                "group_id integer, " +                "thread_id integer" +                 ")");    }    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {        // TODO Auto-generated method stub    }}

View Code

定义内容提供者

public class GroupProvider extends ContentProvider {    GroupOpenHelper helper;    private SQLiteDatabase db;        static final int CODE_GROUPS_INSERT = 0;        UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);        private final String authority = "com.itheima.momo";    {        //添加匹配规则        //authority是主机名，//path是要匹配的路径        matcher.addURI(authority , "groups/insert", CODE_GROUPS_INSERT);    }    @Override    public boolean onCreate() {        helper = GroupOpenHelper.getInstance(getContext());        db = helper.getWritableDatabase();        return false;    }    @Override    public Cursor query(Uri uri, String[] projection, String selection,            String[] selectionArgs, String sortOrder) {        return null;    }    @Override    public String getType(Uri uri) {        return null;    }    @Override    public Uri insert(Uri uri, ContentValues values) {        switch (matcher.match(uri)) {        case CODE_GROUPS_INSERT:            long rawId= db.insert("groups", null, values);            //插入失败            if(rawId == -1){                return null;            }            else{                //把返回的行id，拼接在uri的后面，然后返回                return ContentUris.withAppendedId(uri, rawId);            }                    default:            break;        }        return null;    }    @Override    public int delete(Uri uri, String selection, String[] selectionArgs) {        return 0;    }    @Override    public int update(Uri uri, ContentValues values, String selection,            String[] selectionArgs) {        return 0;    }}

GroupProvider.java

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.itheima.momo"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="8"        android:targetSdkVersion="17" />    <uses-permission android:name="android.permission.READ_SMS"/>    <uses-permission android:name="android.permission.READ_CONTACTS"/>    <uses-permission android:name="android.permission.WRITE_SMS"/>    <uses-permission android:name="android.permission.SEND_SMS"/>    <application        android:allowBackup="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity            android:name="com.itheima.momo.ui.activity.MainActivity"            android:label="@string/app_name" >            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>                <activity android:name="com.itheima.momo.ui.activity.ConversationDetailActivity"            android:windowSoftInputMode="stateUnspecified|adjustResize"            ></activity>                <activity android:name="com.itheima.momo.ui.activity.NewMsgActivity"></activity>                <receiver android:name="com.itheima.momo.receiver.SendSmsReceiver">            <intent-filter >                <action android:name="com.itheima.momo.sendsms"/>            </intent-filter>        </receiver>                <provider android:name="com.itheima.momo.provider.GroupProvider"            android:exported="true"            android:authorities="com.itheima.momo"            ></provider>    </application></manifest>

AndroidManifest.xml

import android.content.ContentValues;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.Button;import com.itheima.momo.R;import com.itheima.momo.base.BaseFragment;import com.itheima.momo.globle.Constant;public class GroupFragment extends BaseFragment {    private Button bt_group_newgroup;    @Override    public View initView(LayoutInflater inflater, ViewGroup container,            Bundle savedInstanceState) {        // TODO Auto-generated method stub        View view = inflater.inflate(R.layout.fragment_group, null);        bt_group_newgroup = (Button) view.findViewById(R.id.bt_group_newgroup);        return view;    }    @Override    public void initListener() {        bt_group_newgroup.setOnClickListener(this);    }    @Override    public void initData() {        // TODO Auto-generated method stub    }    @Override    public void processClick(View v) {        switch (v.getId()) {        case R.id.bt_group_newgroup:            ContentValues values = new ContentValues();            values.put("name", "天下英雄基本也就这几个了");            values.put("create_date", System.currentTimeMillis());            values.put("thread_count", 0);            getActivity().getContentResolver().insert(Constant.URI.URI_GROUP_INSERT, values);            break;        }    }}

GroupFragment.java

自动下拉列表条

package com.itheima.momo.adapter;import com.itheima.momo.R;import android.content.Context;import android.database.Cursor;import android.view.View;import android.view.ViewGroup;import android.widget.CursorAdapter;import android.widget.TextView;public class AutoSearchAdapter extends CursorAdapter {    @SuppressWarnings("deprecation")    public AutoSearchAdapter(Context context, Cursor c) {        super(context, c);    }        @Override    public View newView(Context context, Cursor cursor, ViewGroup parent) {        return View.inflate(context, R.layout.item_auto_search_tv, null);    }        @Override    public void bindView(View view, Context context, Cursor cursor) {        ViewHolder holder = getHolder(view);        holder.tv_autosearch_name.setText(cursor.getString(cursor.getColumnIndex("display_name")));        holder.tv_autosearch_address.setText(cursor.getString(cursor.getColumnIndex("data1")));    }        private ViewHolder getHolder(View view) {        ViewHolder holder = (ViewHolder) view.getTag();        if(holder == null){            holder = new ViewHolder(view);            view.setTag(holder);        }        return holder;    }        class ViewHolder{        private TextView tv_autosearch_name;        private TextView tv_autosearch_address;        public ViewHolder(View view) {            tv_autosearch_name = (TextView) view.findViewById(R.id.tv_autosearch_name);            tv_autosearch_address = (TextView) view.findViewById(R.id.tv_autosearch_address);        }    }        //点击下拉列表条目时的返回值    @Override    public CharSequence convertToString(Cursor cursor) {        return cursor.getString(cursor.getColumnIndex("data1"));    }}

AutoSearchAdapter.java

package com.itheima.momo.ui.activity;import android.content.Intent;import android.database.Cursor;import android.net.Uri;import android.provider.ContactsContract.CommonDataKinds.Phone;import android.text.TextUtils;import android.view.View;import android.widget.AutoCompleteTextView;import android.widget.Button;import android.widget.EditText;import android.widget.FilterQueryProvider;import android.widget.ImageView;import android.widget.TextView;import com.itheima.momo.R;import com.itheima.momo.adapter.AutoSearchAdapter;import com.itheima.momo.base.BaseActivity;import com.itheima.momo.dao.SmsDao;import com.itheima.momo.utils.CursorUtils;import com.itheima.momo.utils.ToastUtils;public class NewMsgActivity extends BaseActivity {    //这个组件显示联系人列表也是使用Adapter来设置列表条目    private AutoCompleteTextView et_newmsg_address;    private EditText et_newmsg_body;    private AutoSearchAdapter adapter;    private ImageView iv_newmsg_select_contact;    private Button bt_newmsg_send;    @Override    public void initView() {        setContentView(R.layout.activity_newmsg);        et_newmsg_address = (AutoCompleteTextView) findViewById(R.id.et_newmsg_address);        et_newmsg_body = (EditText) findViewById(R.id.et_newmsg_body);        iv_newmsg_select_contact = (ImageView) findViewById(R.id.iv_newmsg_select_contact);        bt_newmsg_send = (Button) findViewById(R.id.bt_newmsg_send);                //这是下拉列表的背景        et_newmsg_address.setDropDownBackgroundResource(R.drawable.bg_btn_normal);        //这是下拉列表的竖直偏移        et_newmsg_address.setDropDownVerticalOffset(5);    }    @Override    public void initListener() {        iv_newmsg_select_contact.setOnClickListener(this);        bt_newmsg_send.setOnClickListener(this);    }    @Override    public void initData() {        adapter = new AutoSearchAdapter(this, null);        //给输入框设置adapter，该adapter负责显示输入框的下拉列表        et_newmsg_address.setAdapter(adapter);                adapter.setFilterQueryProvider(new FilterQueryProvider() {                        //这个方法的调用，是用来执行查询            //constraint:用户在输入框中输入的号码，也就是模糊查询的条件            @Override            public Cursor runQuery(CharSequence constraint) {                String[] projection = {                        "data1",                        "display_name",                        "_id"                };                //模糊查询                String selection = "data1 like '%" + constraint + "%'";                Cursor cursor = getContentResolver().query(Phone.CONTENT_URI, projection, selection, null, null);//                CursorUtils.printCursor(cursor);                                //返回cursor，就是把cursor交给adapter                return cursor;            }        });                initTitleBar();    }    @Override    public void processClick(View v) {        switch (v.getId()) {        case R.id.iv_titlebar_back_btn:            finish();            break;        case R.id.iv_newmsg_select_contact:            //跳转至系统提供的联系人选择Activity            Intent intent = new Intent(Intent.ACTION_PICK);            intent.setType("vnd.android.cursor.dir/contact");            //使用startActivityForResult启动，那么选好联系人，该Activity销毁，回调onActivityResult            startActivityForResult(intent, 0);            break;        case R.id.bt_newmsg_send:            String address = et_newmsg_address.getText().toString();            String body = et_newmsg_body.getText().toString();            if(!TextUtils.isEmpty(address) && !TextUtils.isEmpty(body)){                SmsDao.sendSms(this, address, body);            }            break;        }    }    @Override    protected void onActivityResult(int requestCode, int resultCode, Intent data) {        super.onActivityResult(requestCode, resultCode, data);        //data中会携带一个uri，就是用户选择的联系人的uri        Uri uri = data.getData();        if(uri != null){            //查询这个uri，获取联系人的id和是否有号码            String[] projection = {                    "_id",                    "has_phone_number"            };            //不需要where条件，因为uri是“一个”联系人的uri            Cursor cursor = getContentResolver().query(uri, projection, null, null, null);            //不需要判断是否查到，但是必须移动指针            cursor.moveToFirst();            String _id = cursor.getString(0);            int has_phone_number = cursor.getInt(1);                        if(has_phone_number == 0){                ToastUtils.ShowToast(this, "该联系人没有号码");            }            else{                //如果有号码，拿着联系人id去Phone.CONTENT_URI查询号码                String selection = "contact_id = " + _id;                Cursor cursor2 = getContentResolver().query(Phone.CONTENT_URI, new String[]{"data1"}, selection, null, null);                cursor2.moveToFirst();                String data1 = cursor2.getString(0);                                et_newmsg_address.setText(data1);                //内容输入框获取焦点                et_newmsg_body.requestFocus();            }        }    }        private void initTitleBar() {        findViewById(R.id.iv_titlebar_back_btn).setOnClickListener(this);        ((TextView)findViewById(R.id.tv_titlebar_title)).setText("发送短信");    }}

NewMsgActivity.java

对话框默认不支持文本输入，手动把一个输入框设置为对话框的内容，让android自动弹出输入键盘

//本类中提供静态方法，获取本类的对象。
public static void showDialog(Context context, String title, OnInputDialogListener onInputDialogListener){
InputDialog dialog = new InputDialog(context, title, onInputDialogListener);
//对话框默认不支持文本输入，手动把一个输入框设置为对话框的内容，Android自动对其进行设置（设置的文本框会被布局文件覆盖）
dialog.setView(new EditText(context));
dialog.show();
}

TextView添加图标

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:padding="10dp"    android:background="@drawable/selector_item_grouplist_bg"    >    <!--最左边的图片就是孤零零的图片上面没有加上任何的功能，所以直接在textview中利用属性实现  -->    <TextView         android:id="@+id/tv_grouplist_name"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="群组名字"        android:textSize="16sp"        android:drawableLeft="@drawable/img_group"        android:drawablePadding="5dp"        android:gravity="center_vertical"        />    <TextView         android:id="@+id/tv_grouplist_date"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="12:78pm"        android:textSize="15sp"        android:layout_alignParentRight="true"        android:layout_centerVertical="true"        />    </RelativeLayout>

View Code

改变ListView的点击背景

1、去掉原来的背景

2、设置ITEM的背景

----------------------------------------------------------------------------------------

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:drawable="@color/item_grouplist_normal" android:state_pressed="false"></item>
<item android:drawable="@color/item_grouplist_press" android:state_pressed="true"></item>

</selector>

--------------------------------------------------------------------------------------------------

<?xml version="1.0" encoding="utf-8"?>
<resources>
<color name="item_grouplist_normal">#ffffff</color>
<color name="item_grouplist_press">#33666666</color>
</resources>

自定义数据库刷新

import com.itheima.momo.dao.GroupOpenHelper;

import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;

public class GroupProvider extends ContentProvider {

GroupOpenHelper helper;
private SQLiteDatabase db;
private static final String TABLE_GROUPS = "groups";
private static final String TABLE_THREAD_GROUP = "thread_group";

private static final String authority = "com.itheima.momo";
public static final Uri BASE_URI = Uri.parse("content://" + authority);

static final int CODE_GROUPS_INSERT = 0;
static final int CODE_GROUPS_QUERY = 1;
static final int CODE_GROUPS_UPDATE = 2;
static final int CODE_GROUPS_DELETE = 3;
static final int CODE_THREAD_GROUP_INSERT = 4;
static final int CODE_THREAD_GROUP_QUERY = 5;
static final int CODE_THREAD_GROUP_UPDATE = 6;
static final int CODE_THREAD_GROUP_DELETE = 7;

UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);
{
//添加匹配规则
matcher.addURI(authority , "groups/insert", CODE_GROUPS_INSERT);
matcher.addURI(authority , "groups/query", CODE_GROUPS_QUERY);
matcher.addURI(authority , "groups/update", CODE_GROUPS_UPDATE);
matcher.addURI(authority , "groups/delete", CODE_GROUPS_DELETE);
matcher.addURI(authority , "thread_group/insert", CODE_THREAD_GROUP_INSERT);
matcher.addURI(authority , "thread_group/query", CODE_THREAD_GROUP_QUERY);
matcher.addURI(authority , "thread_group/update", CODE_THREAD_GROUP_UPDATE);
matcher.addURI(authority , "thread_group/delete", CODE_THREAD_GROUP_DELETE);
}
@Override
public boolean onCreate() {
helper = GroupOpenHelper.getInstance(getContext());
db = helper.getWritableDatabase();
return false;
}

@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {

switch (matcher.match(uri)) {
//这个是表示不同的表，根据id判断出不同的表然后选择插入。
case CODE_GROUPS_QUERY:
Cursor cursor = db.query(TABLE_GROUPS, projection, selection, selectionArgs, null, null, sortOrder);

//监视uri上数据改变一个的内容观察者
//只要该uri上的数据改变，内容观察者会立刻发现，重新查询
cursor.setNotificationUri(getContext().getContentResolver(), BASE_URI);
return cursor;
case CODE_THREAD_GROUP_QUERY:
cursor = db.query(TABLE_THREAD_GROUP, projection, selection, selectionArgs, null, null, sortOrder);
cursor.setNotificationUri(getContext().getContentResolver(), BASE_URI);
return cursor;
default:
throw new IllegalArgumentException("未识别的uri:" + uri);
}
}

@Override
public String getType(Uri uri) {
return null;
}

@Override
public Uri insert(Uri uri, ContentValues values) {
switch (matcher.match(uri)) {
case CODE_GROUPS_INSERT:
long rawId = db.insert(TABLE_GROUPS, null, values);
//插入失败
if(rawId == -1){
return null;
}
else{
//这个是自己创建的数据库只能调用notifychange方法，让其帮忙刷新。
getContext().getContentResolver().notifyChange(BASE_URI, null);
//把返回的行id，拼接在uri的后面，然后返回
return ContentUris.withAppendedId(uri, rawId);
}
case CODE_THREAD_GROUP_INSERT:
rawId = db.insert(TABLE_THREAD_GROUP, null, values);
//插入失败
if(rawId == -1){
return null;
}
else{
getContext().getContentResolver().notifyChange(BASE_URI, null);
//把返回的行id，拼接在uri的后面，然后返回
return ContentUris.withAppendedId(uri, rawId);
}

default:
throw new IllegalArgumentException("未识别的uri:" + uri);
}
}

@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
switch (matcher.match(uri)) {
case CODE_GROUPS_DELETE:
int number = db.delete(TABLE_GROUPS, selection, selectionArgs);
getContext().getContentResolver().notifyChange(BASE_URI, null);
return number;
case CODE_THREAD_GROUP_DELETE:
number = db.delete(TABLE_THREAD_GROUP, selection, selectionArgs);
getContext().getContentResolver().notifyChange(BASE_URI, null);
return number;
default:
throw new IllegalArgumentException("未识别的uri:" + uri);
}
}

@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
switch (matcher.match(uri)) {
case CODE_GROUPS_UPDATE:
int number = db.update(TABLE_GROUPS, values, selection, selectionArgs);
getContext().getContentResolver().notifyChange(BASE_URI, null);
return number;
case CODE_THREAD_GROUP_UPDATE:
number = db.update(TABLE_THREAD_GROUP, values, selection, selectionArgs);
getContext().getContentResolver().notifyChange(BASE_URI, null);
return number;
default:
throw new IllegalArgumentException("未识别的uri:" + uri);
}
}

}

final

在Java中声明属性、方法和类时，可使用关键字final来修饰。

final变量即为常量，只能赋值一次；

final方法不能被子类重写；

final类不能被继承。

编辑框设置图标

LIstview去掉横线和背景设置

在LISTVIEW中隐藏输入法软键盘

lv_search_list.setOnScrollListener(new OnScrollListener() {

@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
//输入法管理器
//隐藏输入法软键盘
InputMethodManager imm = (InputMethodManager) getActivity().getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(getActivity().getWindow().getDecorView().getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
}

@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {

}
});

限制TextViewW文字行数，以及添加“...”

ImageView显示方式（对齐、裁剪centercrop等）

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android 学习随笔二十八（应用小知识点小结 ）

final

android 学习随笔二十八（应用小知识点小结）