Delay handler inside a loop in android

Question

I am trying to insert the handler to the loop but it makes it happen only once.

for(int i = 0;i<4;i++) {
    btn1.setBackgroundColor(Color.RED);
    new Handler().postDelayed(new Runnable() {
        @Override
        public void run() {
            btn1.setBackgroundColor(Color.GREEN);
        }
    }, 2000);
}

ATP · Accepted Answer · 2022-04-10T16:58:50.233

0

If you want the button to change between red and green with a delay of 2 seconds you can try something like this:

for(int i = 0;i<4;i++) {
                new Handler().postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        btn1.setBackgroundColor(Color.RED);
                    }
    }, 2000*2*i);
    new Handler().postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        btn1.setBackgroundColor(Color.GREEN);
                    }
    }, 2000*(2*i+1));
}

When using

new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    btn1.setBackgroundColor(Color.GREEN);
                }
            }, 2000)

you set the delay to a fixed value. to make the button blink the delay has to be dynamic and changed every loop iteration.

edited Apr 10 '22 at 16:58

answered Apr 10 '22 at 16:09

ATP

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Thanks for the answer, but it does not work for me, the loop is done only once – Gilad azoolay Apr 10 '22 at 16:32
@גלעדאזולאי what is your goal? – ATP Apr 10 '22 at 16:33
@Giladazoolay the loop is done 4 times. you just do not see any effect because there is no delay between the loops. they happen immediately without waiting 2 seconds like the handler – ATP Apr 10 '22 at 16:45
the goal is that the button change color i times – Gilad azoolay Apr 10 '22 at 16:56
@Giladazoolay use the first code snippet I edited it – ATP Apr 10 '22 at 16:59

Delay handler inside a loop in android

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