Question

I’m trying my app format some images in the screen after the Activity loads. The problem is while inside onCreate(), onResume() methods my ImageView have width and height=0. How can I run some code after the views are resized?
I test onPostResume() but it dont work =(

Answer 1

Views in Android do not have fixed size/position like in Blackberry or iPhone; instead, they are layed out dynamically. Layout happens much later than onCreate/onResume, and theoretically can happen many times. Every view has methods onMeasure and onLayout which are responsible for that. Only after onLayout method returns you can tell the view’s size and position. Before that the view’s size is 0 and position is 0 (as you’ve noticed).

So it makes little sense trying to get ImageView’s size in onCreate/onResume because onLayout hasn’t yet been called at that point.

Instead, override onLayout like this and do your stuff there:

public class MyImageView extends ImageView {
    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
        // at this point size and position are known
        int h = getHeight();
        int w = getWidth();
        doSomethingCool(h,w);
    }
}