Android通知图标无法显示

Question

我写了一些Android代码来显示图标。但是，运行代码后，图标可以显示但不会消失（显示关闭）。它总是在通知栏上。如果可能的话，你能帮我看一下吗？ THX

 final Notification.Builder mBuilder = new Notification.Builder(getApplicationContext());
        final NotificationManager mNotifyManager =
                (NotificationManager) getSystemService(
                        Context.NOTIFICATION_SERVICE);
        final int mNotifyId = 1;
        final String TITLE = "abc";
        final String MSG = "abc is active.";


    Bitmap largeIcon = BitmapFactory.decodeResource(getResources(), R.mipmap.ic_notification);
            mBuilder.setContentTitle(TITLE)
                    .setContentText(MSG)
                    .setSmallIcon(R.mipmap.ic_dark)
                    .setLargeIcon(largeIcon)
                    .setOngoing(true)
                    .setAutoCancel(false);


        final Handler handler= new Handler();

        final Runnable r = new Runnable() {
            public void run() {
                mNotifyManager.notify(mNotifyId, mBuilder.build());
                mNotifyManager.cancel(mNotifyId);
                handler.postDelayed(this, 1000);
            }
        };

        handler.postDelayed(r, 1000);