外部存储设备的状态变化时发出的广播

对比不同状态下的广播

1. 插入外部SD卡时：

2. 移除外部SD卡时：

3. 连接PC进入USB大容量存储模式时：

4. 连接PC退出USB大容量存储模式时：

代码实现监听

public void startListen() {     IntentFilter intentFilter = new IntentFilter(Intent.ACTION_MEDIA_MOUNTED);     intentFilter.setPriority(1000);       intentFilter.addAction(Intent.ACTION_MEDIA_UNMOUNTED);     intentFilter.addAction(Intent.ACTION_MEDIA_REMOVED);     intentFilter.addAction(Intent.ACTION_MEDIA_SHARED);     intentFilter.addAction(Intent.ACTION_MEDIA_BAD_REMOVAL);      intentFilter.addAction(Intent.ACTION_MEDIA_SCANNER_STARTED);     intentFilter.addAction(Intent.ACTION_MEDIA_SCANNER_FINISHED);      intentFilter.addAction(Intent.ACTION_MEDIA_CHECKING);     intentFilter.addAction(Intent.ACTION_MEDIA_EJECT);     intentFilter.addAction(Intent.ACTION_MEDIA_NOFS);     intentFilter.addAction(Intent.ACTION_MEDIA_BUTTON);     intentFilter.addAction(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);     intentFilter.addDataScheme("file");     registerReceiver(broadcastRec, intentFilter); }  private final BroadcastReceiver broadcastRec = new BroadcastReceiver() {       @Override       public void onReceive(Context context, Intent intent) {           String action = intent.getAction();          Log.d("MediaAction", action);         if (action.equals("android.intent.action.MEDIA_MOUNTED"))         {            //todo         } else if (action.equals(Intent.ACTION_MEDIA_UNMOUNTED))          {            //todo         }else if (action.equals(Intent.ACTION_MEDIA_SCANNER_STARTED)){         }else if (action.equals(Intent.ACTION_MEDIA_SCANNER_FINISHED)){         }else if (action.equals(Intent.ACTION_MEDIA_SHARED)){         }else {          }       }   };