Question

I am trying to do an animation where the clip size changes and thus the size of an drawn bitmap changes, but I want it to look like an animation. Basically, what I did was in the views onDraw() method, i have made code that changes the clip size as necessary and every time it draws the bitmap, the image size is changed.

I am confused as to how to call the onDraw method repeatedly on the View with a certain pause in between…lets say 100ms

My current code just creates a runnable on the UI thread that does this. However, it fails miserably 🙁 I am not sure what to do.

final Handler handler = new Handler();
    Runnable runnable = new Runnable() {
        public void run() {
            DrawnCircle hnd = ((DrawnCircle)AVE.MAIN.findViewById(R.id.drawnCircle1));
            while(hnd.getSweep()<=360){
                hnd.setSweep(hnd.getSweep()+1);
                hnd.invalidate();
                try {Thread.sleep(100);} catch (InterruptedException e) {}
            }
        }
    };
    handler.post(runnable);

thank you for your time and effort

Answer 1

I’m just learning animation myself, but how about using Android’s ValueAnimator class? If you’re trying to animate an integer value you could do something like this:

ValueAnimator anim = ValueAnimator.ofInt(fromValue, toValue);
anim.setDuration(1000);
anim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
    hnd.setSweep(anim.getAnimatedValue(););
    hnd.invalidate();
});

anim.start();