UIView beginAnimations with subviews

Question

I have a nice and easy \"zoom\" animation for a view, which starts as a dot and animates up to full screen size:

        [UIView beginAnimations:nil context:NULL];
         


        

Answer 1

I just ran in to the same problem, and the solution was surprisingly easy. Whereas modifying the frame size only affects the current view, not the subviews (as you noticed), the transform property applies to the subviews as well.

I'm trying to do the reverse of what you're doing (have a subview that appears to 'drop' on to the top of an existing view when displayed, rather than zoom from the center). This code works for me:

self.transform = CGAffineTransformMakeScale(2,2);
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.25];
self.transform = CGAffineTransformMakeScale(1,1);
self.alpha = 1.0;
[UIView commitAnimations];

Try setting self.transform to CGAffineTransformMakeScale(0,0) before beginning the animation, and set it back to (1,1) before committing. Don't modify the frame at all - leave it at the size you want the view to have after the animation completes.

Answer 2

You can always use the auto-sizing in the interface builder . This way you can specify the left/margin which you don't want to change and the axis along which you want the particular sub-view to resize to .