Android 注册广播的两种方式对比

 <!-- 桌面 --> 
<receiver android:name=".widget.DeskWidgeWeather"> 
<meta-data android:name="android.appwidget.provider" android:resource="@xml/widget_weather_provider" /> 
<intent-filter> 
 <action android:name="android.appwidget.action.APPWIDGET_UPDATE"/> 
 <action android:name="action_weather"/> 
</intent-filter> 
lt;/receiver> 

SdcardStateChanageReceiver sdcardStateReceiver; 
@Override 
protected void onCreate(Bundle savedInstanceState) 
{ 
 super.onCreate(savedInstanceState); 
 IntentFilter filter = new IntentFilter(); 
 filter.addAction(Intent.ACTION_MEDIA_REMOVED); 
 filter.addAction(Intent.ACTION_MEDIA_EJECT); 
 filter.addAction(Intent.ACTION_MEDIA_MOUNTED); 
 filter.addDataScheme("file"); 
 sdcardStateReceiver = new SdcardStateChanageReceiver();  
 registerReceiver(sdcardStateReceiver,filter); 
} 
@Override 
protected void onDestroy(){ 
 unregisterReceiver(sdcardStateReceiver); 
} 
class SdcardStateChanageReceiver extends BroadcastReceiver{ 
 
 @Override 
 public void onReceive(Context context, Intent intent) 
 { 
 String state=android.os.Environment.getExternalStorageState(); 
 System.out.println("SDCard 发生改变! 状态："+state); 
 //checkSDCard(); 
 } 
 public void checkSDCard(){ 
 String state=android.os.Environment.getExternalStorageState(); 
 System.out.println(state); 
 if(state.equals(android.os.Environment.MEDIA_REMOVED ) || state .equals(android.os.Environment.MEDIA_UNMOUNTED)){ 
  System.out.println("SDCard 已卸载!"); 
 } 
 } 
}