Simple UIView animation move doesn't work - objective-c

Question

I have no idea, why it is not working.
All I want to do is a simple UIView animation in the viewDidLoad.
Here's my code:
[UIView animateWithDuration:3.0f animations:^{
[self.headline setCenter:CGPointMake(0.0, 200.0)];
}];
Nothing happens. When I test the general approach of calling a animation method on that particular object like this:
[UIView animateWithDuration:3.0f animations:^{
[self.headline setAlpha:0.0];
}];
it works!!! Why am I not able to move the view across the screen? I am using latest Xcode 4.5.
Thanks for any advice!
UPDATE:
When I add a view manually in code it works. But for the UIViews I create as Outlets in the Interface Builder it doesn't work.
UILabel *testLabel = [[UILabel alloc] initWithFrame:CGRectMake(0.0, 0.0, 200.0, 100.0)];
testLabel.backgroundColor = [UIColor redColor];
[self.view addSubview:testLabel];
[UIView animateWithDuration:3.0 animations:^{
testLabel.center = CGPointMake(0.0, 200);
}];
So obviously I am doing something wrong in the .xib file

Answer 1

Dont do it in viewDidLoad. The view is not pressent at that time yet.
Try it in viewDidAppear.

Answer 2

Well, I think the reason for the missing animation was the fact that I called a different push navigation animation from the view controller that was pushing the actual view on screen:
- (IBAction)goForSelection:(id)sender
{
SelectionViewController *selectionViewController = [[SelectionViewController alloc] initWithNibName:#"SelectionViewController" bundle:nil];
//[self.navigationController pushViewController:selectionViewController animated:YES];
[UIView transitionWithView:self.navigationController.view duration:1.0 options:UIViewAnimationOptionTransitionFlipFromRight animations:^{
[self.navigationController pushViewController:selectionViewController animated:NO];
} completion:^(BOOL finished) {
[selectionViewController startIntroAnimation];
}];
}
First I checked what happens when I use the default navigation controller segue. And to my surprise the animation did start. Then I inserted the call to the [selectionViewController startIntroAnimation] to the completion block and this works as well.