最近在项目中需要对外部存储设备的状态进行监听，所以整理了此笔记，以便日后查看。

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 { 
        }  
    }  
};