iPhone Curl Left and Curl Right transitions

Question

I am looking for a way to do a UIViewAnimationTransitionCurlUp or UIViewAnimationTransitionCurlDown transition on the iPhone but instead of top to bottom, do it from the left to right (or top/bottom in landscape mode). I've seen this asked aroud the internet a few times but none sems to get an answer. However I feel this is doable.

I have tried changing the View's transform and the view.layer's transform but that didn't affect the transition. Since the transition changes when the device changes orientation I presume there is a way to fool the device to use the landscape transition in portrait mode and vice versa?

Answer 1

I don't think there is a way beyond writing a custom animation.

More importantly you probably shouldn't try to it. The curl up and curl down are part of the user interface grammar that tells the user that a view is being lifted up or put down over the existing view. It's supposed to be like a sticky note being put down and then removed. A left<->right curl will most likely be interpreted as the something like ripping a page out of a book. It will confuse users.

Whenever you find yourself trying to do something in the interface that the standard API doesn't do easily, you should ask yourself whether such a novel method will communicate something important to user and whether it is similar to the existing interface grammar. If not, then you shouldn't bother.

Unusual interfaces have an initial wow factor but they lead to frustration and errors in day-to-day use. They can also cause Apple to refuse your app.

Answer 2

I actually managed to achieve this effect by changing the orientation of my UIViewController. The strange thing is, I had my controller nesten in another one when it wasn't working, but when I set him as the immediate view controller, it worked.

Code that does it:

In a UIViewController that is the main view controller in my app delegate and only allows landscape orientation (as you see in the 2nd method below) I have the following:

-(void)goToPage:(int)page flipUp:(BOOL)flipUp {

     //do stuff...

     // start the animated transition
     [UIView beginAnimations:@"page transition" context:nil];
     [UIView setAnimationDuration:1.0];
     [UIView setAnimationTransition:flipUp ? UIViewAnimationTransitionCurlUp : UIViewAnimationTransitionCurlDown forView:self.view cache:YES];

     //insert your new subview
     //[self.view insertSubview:currentPage.view atIndex:self.view.subviews.count];

      // commit the transition animation
      [UIView commitAnimations];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
     return (interfaceOrientation == UIInterfaceOrientationLandscapeRight);
}

Answer 3

could you post your working code for the curl left to right? thanks in advance

Answer 4

Dimitris can you post your source code for curl left to right ... i searched lot but didnt get any solution.Thanks in advance

Answer 5

It's possible to do curls in any of the four directions by using a container view. Set the container view's transformation to the angle you want and then do the curl by adding your view to the container view, not your app's main view which does not have a transformed frame:

NSView* parent = viewController.view; // the main view
NSView* containerView = [[[UIView alloc] initWithFrame:parent.bounds] autorelease];
containerView.transform = CGAffineTransformMakeRotation(<your angle here, should probably be M_PI_2 * some integer>);
[parent addSubview:containerView]; 

[UIView beginAnimations:nil context:nil];
[UIView setAnimationTransition:UIViewAnimationTransitionCurlUp forView:containerView cache:YES];
[containerView addSubview:view];
[UIView commitAnimations];