Android BroadcastReceiver的基本用法

如下图所示，点击menu右面的broadcast会发送一条广播，广播接受者接受信息后，打印一些调试信息。

下面看代码：

布局文件layout/main.xml

<?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/text1" 
    android:layout_width="fill_parent"  
    android:layout_height="wrap_content"  
    android:text="Your debug will appear here" 
    />
</LinearLayout>

menu/main_menu.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"> 
    <group android:id="@+id/menuGroup_Main"> 
        <item android:id="@+id/menu_clear" 
        android:title="clear" /> 
        <item android:id="@+id/menu_send_broadcast" 
            android:title="broadcast" /> 
    </group>
</menu>

MainActivity

package com.xiyang.android.broadcast;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.TextView;

public class MainActivity extends Activity {
    private static final String tag = "TestReceiver";
    
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }
    @Override 
    public boolean onCreateOptionsMenu(Menu menu){  
        super.onCreateOptionsMenu(menu); 
        MenuInflater inflater = getMenuInflater(); //from activity 
        inflater.inflate(R.menu.main_menu, menu); 
        return true; 
    } 
    @Override 
    public boolean onOptionsItemSelected(MenuItem item){  
        appendMenuItemText(item); 
        if (item.getItemId() == R.id.menu_clear){ 
            this.emptyText(); 
            return true; 
        } 
        if (item.getItemId() == R.id.menu_send_broadcast){ 
            this.testSendBroadcast();
            return true; 
        } 
        return true; 
    } 
    private TextView getTextView(){ 
        return (TextView)this.findViewById(R.id.text1); 
    } 
    private void appendMenuItemText(MenuItem menuItem){ 
       String title = menuItem.getTitle().toString(); 
       TextView tv = getTextView();  
       tv.setText(tv.getText() + "\n" + title); 
    } 
    private void emptyText(){ 
          TextView tv = getTextView(); 
          tv.setText(""); 
    } 
    private void testSendBroadcast() 
    { 
        //Print out what your running thread id is 
        Utils.logThreadSignature(tag); 
         
        //Create an intent with an action 
        Intent broadcastIntent = new Intent("com.androidbook.intents.testbc"); 
        //load up the intent with a message 
        //you want to broadcast 
        broadcastIntent.putExtra("message", "Hello world"); 
         
        //send out the broadcast 
        //there may be multiple receivers receiving it 
        this.sendBroadcast(broadcastIntent); 
         
        //Log a message after sending the broadcast 
        //This message should appear first in the log file 
        //before the log messages from the broadcast 
        //because they all run on the same thread 
        Log.d(tag,"after send broadcast from main menu"); 
    } 
}

广播接收者

package com.xiyang.android.broadcast;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

public class TestReceiver extends BroadcastReceiver {
    private static final String tag = "TestReceiver";

    @Override
    public void onReceive(Context context, Intent intent) {
        Utils.logThreadSignature(tag);
        Log.d("TestReceiver", "intent=" + intent);
        String message = intent.getStringExtra("message");
        Log.d(tag, message);
    }

}

一个工具类

package com.xiyang.android.broadcast;

import android.util.Log;

public class Utils  
{ 
    public static long getThreadId() 
    { 
        Thread t = Thread.currentThread(); 
        return t.getId(); 
    } 
    public static String getThreadSignature() 
    { 
        Thread t = Thread.currentThread(); 
        long l = t.getId(); 
        String name = t.getName(); 
        long p = t.getPriority(); 
        String gname = t.getThreadGroup().getName(); 
        return (name + ":(id)" + l + ":(priority)" + p 
                + ":(group)" + gname); 
    } 
    public static void logThreadSignature(String tag) 
    { 
        Log.d(tag, getThreadSignature()); 
    } 
    public static void sleepForInSecs(int secs) 
    { 
        try 
        { 
            Thread.sleep(secs * 1000); 
        } 
        catch(InterruptedException x) 
        { 
            throw new RuntimeException("interrupted",x); 
        } 
    } 
} 

清单文件注册服务

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.xiyang.android.broadcast"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="10" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".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>
        <receiver android:name=".TestReceiver"> 
            <intent-filter> 
                <action android:name="com.androidbook.intents.testbc"/> 
            </intent-filter> 
        </receiver> 
    </application>
</manifest>

说明：

1、在另外一个应用中发送广播，本程序中的广播接收者也能后获取广播，触发接收事件。

2、在本应用中，创建两个广播接收者，当在MainActivity中发送广播时，两个接收程序都能进行处理。比如再创建一个TestReceiver2.java，发送一条广播时，如下图所示：

3、从以上的日志也可以看出，广播接收程序都是在主线程上执行。

4、广播接收程序必须在10s内执行完毕。