Android监听数据表（ContentObserver）

private ContentObserver mDownloadsObserver = new DownloadsChangeObserver(Downloads.CONTENT_URI);
private class DownloadsChangeObserver extends ContentObserver {
        public DownloadsChangeObserver(Uri uri) {
            super(new Handler());
        }
        @Override
        public void onChange(boolean selfChange) {｝ 
        }