From Android Developers, we can use FileObserver to know files or folders changed on sdcard.
We usually use this to implement.
public class StorageMonitor extends FileObserver {
public StorageMonitor(String path) {
super(path);
}
@Override
public void onEvent(int event, String path) {
switch (event) {
case FileObserver.ACCESS:
Log.i("FileObserver", "ACCESS: " + path);
break;
case FileObserver.ATTRIB:
Log.i("FileObserver", "ATTRIB: " + path);
break;
case FileObserver.CLOSE_NOWRITE:
Log.i("FileObserver", "CLOSE_NOWRITE: " + path);
break;
case FileObserver.CLOSE_WRITE:
Log.i("FileObserver", "CLOSE_WRITE: " + path);
break;
case FileObserver.CREATE:
Log.i("FileObserver", "CREATE: " + path);
break;
case FileObserver.DELETE:
Log.i("FileObserver", "DELETE: " + path);
break;
case FileObserver.DELETE_SELF:
Log.i("FileObserver", "DELETE_SELF: " + path);
break;
case FileObserver.MODIFY:
Log.i("FileObserver", "MODIFY: " + path);
break;
case FileObserver.MOVE_SELF:
Log.i("FileObserver", "MOVE_SELF: " + path);
break;
case FileObserver.MOVED_FROM:
Log.i("FileObserver", "MOVED_FROM: " + path);
break;
case FileObserver.MOVED_TO:
Log.i("FileObserver", "MOVED_TO: " + path);
break;
case FileObserver.OPEN:
Log.i("FileObserver", "OPEN: " + path);
break;
default:
Log.i("FileObserver", "DEFAULT(" + event + "): " + path);
break;
}
}
}
And start StorageMonitor in onCreat().
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String sdcard = Environment.getExternalStorageDirectory().getAbsolutePath();
StorageMonitor storageMonitor = new StorageMonitor(sdcard);
storageMonitor.startWatching();
}
Launched application and modified files/folders on sdcard. Then I cannot see any event printed in logcat. I tried several Android Phones and versions (HTC ONE X 4.2.2, Samsung Note3 4.4.2, Google Nexus5 5.0...etc). FileObserver worked well in some Android Phones, for example, HTC ONE X 4.2.2 always passed.
Last, I try to use other constructor of FileObserver. It works for all!!
public StorageMonitor(String path) {
super(path, FileObserver.ALL_EVENTS);
}
God, is this Google bug?
