Question

I’m having some trouble getting a view to flip. I have the following code in my View Controller:

- (void)loadFlipsideViewController {     ProblemViewFlipController *viewController = [[ProblemViewFlipController alloc] initWithNibName:@'ProblemViewFlip' bundle:nil];     self.problemViewFlipController = viewController;     [viewController release]; }   - (void) flipView {      if (problemViewFlipController == nil) {         [self loadFlipsideViewController];     }      UIView *mainView = self.view;     UIView *flipView = problemViewFlipController.view;      [UIView beginAnimations:nil context:NULL];     [UIView setAnimationDuration:1];      [UIView setAnimationTransition:([mainView superview] ? UIViewAnimationTransitionFlipFromLeft : UIViewAnimationTransitionFlipFromRight) forView:self.view cache:YES];      if ([flipView superview])     {         [flipView removeFromSuperview];         [self.view addSubview:mainView];     }     else     {         [mainView removeFromSuperview];         [self.view addSubview:flipView];     }      [UIView commitAnimations]; } 

The problem is, is that when I call flipView, the view is replaced with a blank view (i.e. nothing in the view I’m flipping to is displayed).

Is there something obvious I’m missing here? (I suspect there is!)

Answer 1

Not positive, but I think you need to use a ‘controller’ to flip the views. Looks like you’re using one of the flipped views as the controller. Just add a root controller to flip your views.

Code like this should work from the root controller:

[UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:1]; [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:self.view cache:YES]; // self.view is the root controller's view [mainViewController viewWillAppear:YES]; [flipViewController viewWillDisappear:YES]; [flipViewController.view removeFromSuperview]; [self.view  addSubview:mainViewController.view]; [flipViewController viewDidDisappear:YES]; [mainViewController viewDidAppear:YES]; [UIView commitAnimations];