Broadcast Reveiver作用

 Broadcast Reveiver作用以及為何要引入（用來接收系統以及自定義消息的）
在系統內通知和判定執行狀態
1，系統執行狀態，開機了，TF卡插拔，准備關機，電量低了，
2，自定義執行狀態，發消息提示更新界面

點擊後會打log：順序是testbroadcast2，testbroadcast

activity代碼-----

[java]
package com.paoyx; 
import android.app.Activity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
public class BroadcastActivity extends Activity { 
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.main); 
        //設置按鈕  
        Button button = new Button(this); 
        button.setText("send message"); 
        setContentView(button); 
        button.setOnClickListener(new OnClickListener() { 
            //按鈕點擊事件  
            public void onClick(View v) { 
                //設置intent傳遞數值   
                Intent intent = new Intent(); 
                intent.setAction("com.paoyx.broadcast"); 
                sendBroadcast(intent); 
            } 
        }); 
    } 
} 

package com.paoyx;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class BroadcastActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //設置按鈕
        Button button = new Button(this);
        button.setText("send message");
        setContentView(button);
        button.setOnClickListener(new OnClickListener() {
   //按鈕點擊事件
   public void onClick(View v) {
    //設置intent傳遞數值
    Intent intent = new Intent();
    intent.setAction("com.paoyx.broadcast");
    sendBroadcast(intent);
   }
  });
    }
}
2個receiver代碼---

[html]
package com.paoyx; 
import android.content.BroadcastReceiver; 
import android.content.Context; 
import android.content.Intent; 
import android.util.Log; 
public class MyReceiver extends BroadcastReceiver { 
    public void onReceive(Context context, Intent intent) { 
        // TODO Auto-generated method stub 
        if (intent.getAction().equals("com.paoyx.broadcast")) { 
            Log.i("log","testbroadcast"); 
        } 
    } 
} 

package com.paoyx;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
public class MyReceiver extends BroadcastReceiver {
 public void onReceive(Context context, Intent intent) {
  // TODO Auto-generated method stub
  if (intent.getAction().equals("com.paoyx.broadcast")) {
   Log.i("log","testbroadcast");
  }
 }
}
[html]
package com.paoyx; 
import android.content.BroadcastReceiver; 
import android.content.Context; 
import android.content.Intent; 
import android.util.Log; 
public class MyReceiver2 extends BroadcastReceiver { 
    @Override 
    public void onReceive(Context context, Intent intent) { 
        // TODO Auto-generated method stub 
        if (intent.getAction().equals("com.paoyx.broadcast")) { 
            Log.i("log","testbroadcast2"); 
        } 
    } 
} 

package com.paoyx;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
public class MyReceiver2 extends BroadcastReceiver {
 @Override
 public void onReceive(Context context, Intent intent) {
  // TODO Auto-generated method stub
  if (intent.getAction().equals("com.paoyx.broadcast")) {
   Log.i("log","testbroadcast2");
  }
 }
}
menifest注冊監聽代碼---

[html]
<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.paoyx" 
    android:versionCode="1" 
    android:versionName="1.0" > 
    <uses-sdk android:minSdkVersion="8" /> 
    <application 
        android:icon="@drawable/ic_launcher" 
        android:label="@string/app_name" > 
        <activity 
            android:name=".BroadcastActivity" 
            android:label="@string/app_name" > 
            <intent-filter> 
                <action android:name="android.intent.action.MAIN" /> 
                <category android:name="android.intent.category.LAUNCHER" /> 
            </intent-filter> 
        </activity> 
        //注冊receiver，並設置優先級別，數值大的優先，所以先啟動MyReceiver2 
        <receiver android:name=".MyReceiver"> 
            <intent-filter android:priority="1"> 
                <action android:name="com.paoyx.broadcast"/> 
            </intent-filter> 
        </receiver> 
         <receiver android:name=".MyReceiver2"> 
            <intent-filter android:priority="2"> 
                <action android:name="com.paoyx.broadcast"/> 
            </intent-filter> 
        </receiver> 
    </application> 
</manifest> 

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.paoyx"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-sdk android:minSdkVersion="8" />
    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:name=".BroadcastActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        //注冊receiver，並設置優先級別，數值大的優先，所以先啟動MyReceiver2
        <receiver android:name=".MyReceiver">
            <intent-filter android:priority="1">
                <action android:name="com.paoyx.broadcast"/>
            </intent-filter>
        </receiver>
         <receiver android:name=".MyReceiver2">
            <intent-filter android:priority="2">
                <action android:name="com.paoyx.broadcast"/>
            </intent-filter>
        </receiver>
    </application>
</manifest>