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!");  }  } }