Code only working in ViewDidLoad method

Question

Hello,

I'm using this code after in my ViewDidLoad method :

[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:.5];

self.view.frame = CGRectMake(0, 0, 250, 50);

[UIView commitAnimations];

It's working fine but if I try to do the same thing in an other method in the same implementation file like this :

- (void)setViewMovedUp:(BOOL)movedUp {


            NSLog(@"test movedUp ");
            [UIView beginAnimations:nil context:nil];
            [UIView setAnimationDuration:.5];

            self.view.frame = CGRectMake(0, 0, 250, 50);

            [UIView commitAnimations];



}

Then the animation doesn`t work anymore ( but the NSLog still prints ) . Why would this method behave differently than after "viewDidLoad" ? The setViewMovedUp is called after a button is pressed, therefore I assume that the view is already loaded ? Should I add a condition to make sure that the view is loaded then ?

---

Edit after Michal's comment :

The button I press uses this IBAction in MyViewController.m :

- (IBAction)viewUp {

    MainViewController *moveUp = [[MainViewController alloc] init];
    [moveUp setViewMovedUp:YES];

}

and this is the code in MainViewController.m :

- (void)setViewMovedUp:(BOOL)movedUp {



    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.5];
    self.view.frame = CGRectMake(0, 0, 250, 250);
    [UIView commitAnimations];



}

The Button's IBAction is not communicating well with the MainViewController method (setViewMovedUp) .

In you example it's working well in the same class .

Answer 1

You animate different views, self.containerView in first case, self.view in second.

Answer after Julz's edit:

Now it's clear what you're doing wrong. You can't call animations on an object that you just created because it's not on screen yet. You need to execute the animation code later (at least in the next loop's execution), usually with performSelector:withObject:afterDelay or blocks.

For example like this:

- (void)setViewMovedUp:(BOOL)movedUp {
    [self performSelector:@selector(animateViewUp:) withObject:nil afterDelay:0.0];
}

- (void)animateViewUp:(id)o {
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.5];
    self.view.frame = CGRectMake(0, 0, 250, 250);
    [UIView commitAnimations];
}