我有一个启动广播接收器的警报管理器。这是我的广播接收器:
public class AlarmBrodcastReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent arg1) {
        showNotification(context);
    }
    private void showNotification(Context context) {
        PendingIntent contentIntent = PendingIntent.getActivity(context, 0,
                new Intent(context, MyActivity.class), 0);
        NotificationCompat.Builder mBuilder =
                new NotificationCompat.Builder(context)
                .setSmallIcon(0)
                .setContentTitle("My notification")
                .setContentText("Hello World!");
        mBuilder.setContentIntent(contentIntent);
        mBuilder.setDefaults(Notification.DEFAULT_SOUND);
        mBuilder.setAutoCancel(true);
        NotificationManager mNotificationManager =
            (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
        mNotificationManager.notify(1, mBuilder.build());
    }  
}
广播及时开始,但没有通知,只有声音。文字在哪里?怎么了?是因为我使用的是 API 10 和支持库吗?