检测文件目录的变化

public void musicFileMonitoring() {
    if (fileObserver != null) {
        return;
    }
    fileObserver = new FileObserver("/sdcard/music") {
        @Override
        public void onEvent(int event, @Nullable String path) {
            int e = event & FileObserver.ALL_EVENTS;
            KLog.d("FileObserver-----------." + e);
            switch (e) {
                case FileObserver.CREATE:
                    KLog.d("FileObserver----有创建.");
                    break;
                case FileObserver.DELETE:
                    KLog.d("FileObserver----有删除.");
                    handler.removeMessages(MSG_INQUIRY);
                    handler.sendEmptyMessageDelayed(MSG_INQUIRY, 500);
                    break;
                case FileObserver.CLOSE_WRITE:
                    KLog.d("FileObserver----有更新.");
                    handler.removeMessages(MSG_INQUIRY);
                    handler.sendEmptyMessageDelayed(MSG_INQUIRY, 500);
                    break;
                default:
                    break;
            }

        }
    };
    fileObserver.startWatching();
}