Question

I need to make a layout background flash or blink, changing every second. I wrote this code:

int colours[]={0xff00ff00, 0xffff0000, 0xff0000ff,0xffffffff};
RelativeLayout fondo;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    fondo = (RelativeLayout) findViewById(R.id.fondo);
    this.fondo.setBackgroundColor(colours[0]);
    this.fondo.setOnTouchListener(this);
}

Here is the onTouch method:

public boolean onTouch(View v, MotionEvent event) {
    if(event.getAction() == MotionEvent.ACTION_UP) {
        int i=1;
        long delay= 1000;
        long time = System.currentTimeMillis();

        while(true) {
            long time2 = System.currentTimeMillis();
            long time3 = (time2 - time);
            if (time3 > delay) {
                this.fondo.setBackgroundColor(colours[i]);
                Log.d("DEBUG", "EEEEEEEEEEEEEEEEEEEEEEEEEEEEE");
                time = System.currentTimeMillis();
                i++;
                if (i >= colores.length)
                    i=0;
            }
        }
    }
    return true;
}

My problem is that I can’t change the background color every second, but I can write the Log.d(“DEBUG”) every second.

Answer 1

You should use AnimationDrawable.

If you use an infinite loop in a UI Thread it causes ANR (Android Not Responding) Window

   public boolean onTouch(View v, MotionEvent event) {

        final int DELAY = 100;

        if(event.getAction() == MotionEvent.ACTION_UP) {


            RelativeLayout fondo = (RelativeLayout) findViewById(R.id.fondo);

            ColorDrawable f = new ColorDrawable(0xff00ff00);
            ColorDrawable f2 = new ColorDrawable(0xffff0000);
            ColorDrawable f3 = new ColorDrawable(0xff0000ff);
            ColorDrawable f4 = new ColorDrawable(0xff0000ff);

            AnimationDrawable a = new AnimationDrawable();
            a.addFrame(f, DELAY);
            a.addFrame(f2, DELAY);
            a.addFrame(f3, DELAY);
            a.addFrame(f4, DELAY);
            a.setOneShot(false);

            fondo.setBackgroundDrawable(a); // This method is deprecated in API 16
            // fondo.setBackground(a); // Use this method if you're using API 16
            a.start();
         }
         return true;
    }