Java for循环中的Android处理程序计时器

Question

I have 4 ImageButton and I want to change the images of them randomly FOR 2 seconds. But it doesn't work. What is the problem here? I don't really understand the work of Handlers. I want: change the image of buttonimage, wait 5 seconds, change back the image of buttonimage

for (int i = 0; i < cpu_array.length; i++) {
        actual = cpu_rnd.nextInt(4);
        cpu_array[i] = actual;
        switch (actual) {
        case 0:
            BlueButton.setImageResource(R.drawable.blue_a);
            break;
        case 1:
            RedButton.setImageResource(R.drawable.red_a);
            break;
        case 2:
            GreenButton.setImageResource(R.drawable.green_a);
            break;
        case 3:
            PurpleButton.setImageResource(R.drawable.purple_a);
            break;

        default:
            break;
        }


        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                // Do something after 2s = 2000ms
                BlueButton.setImageResource(R.drawable.blue);
                RedButton.setImageResource(R.drawable.red);
                GreenButton.setImageResource(R.drawable.green);
                PurpleButton.setImageResource(R.drawable.purple);
            }
        }, 2000);

    }

Answer 1

This code worked for me:

   final Button startBookmarksButton = (Button) findViewById(R.id.start_bookmarks_button);
   startBookmarksButton.setBackgroundColor(Color.BLUE);
   new Handler().postDelayed(new Runnable() {
        @Override
        public void run() {
            startBookmarksButton.setBackgroundColor(Color.GREEN);
        }
    }, 2000);

So I think the problem might be somewhere else in your code. Are you sure the random number logic in your loop is working ? Why don't you try getting the delay working first and then debug the random part. Or perhaps the problem is with your images.