Why ListView expand/collapse animation appears much slower in DialogFragment than in Activity

Question

Recently, I find out the ListView expand/collapse animation appears much slower in DialogFragment than in Activity.

In

Answer 1

I find out the key solution to this problem is, fix the dialog size always. Once we fix the size, no resource will be spent to perform size computation during animation.

    final ViewTreeObserver vto = view.getViewTreeObserver();
    vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {

        @SuppressLint("NewApi")
        @SuppressWarnings("deprecation")
        @Override
        public void onGlobalLayout() {
            // Key area to perform optimization. Fix the dialog size!
            // During ListView's rows animation, dialog will never need to 
            // perform computation again.
            int width = dialog.getWindow().getDecorView().getWidth();
            int height = dialog.getWindow().getDecorView().getHeight();
            dialog.getWindow().setLayout(width, height);

            ViewTreeObserver obs = view.getViewTreeObserver();
            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN) {
                obs.removeOnGlobalLayoutListener(this);
            } else {
                obs.removeGlobalOnLayoutListener(this);
            }
        }
    });