How to add an animation to the UIView in viewDidAppear?

Question

I tried to add a animation to viewDidLoad and viewDidAppear, but it doesn't work:

- (void)viewDidAppear:(BOOL)animated{
 [UIView beginAnimations:@"transition" context:NULL];
 [UIView setAnimationTransition:110 forView:self.view cache:YES];
 [UIView commitAnimations];
}

Why?

Answer 1

You are not telling the view which state it should animate to so it won't do anything. You need to place code between beginAnimations:context: and commitAnimations that changes the appearance of the view (e.g. by removing one subview and adding another).

Answer 2

1. You're not using beginAnimations: and commitAnimations correctly. You're supposed to put something in between them that normally wouldn't be animated: e.g. with self.view.alpha = 0.5 you get a fading effect. They have no effect on anything that isn't between them.

2. By the time viewDidAppear: is called, your view, well... has appeared. It's too late to animate anything. What you actually want to do is something like this:

   - (void)showMyViewWithAnimation {
       [UIView beginAnimations:nil context:nil];
       [UIView setAnimationTransition:110 forView:childView cache:YES];
       [parentView addSubview:childView];
       [UIView commitAnimations];
   }
   

   In the example above, childView is what in your example is called self.view.

3. Please write out the name of the transition; no one knows what 110 is by looking at it. It's bad style. </pedantry>