How can I use UIModalTransitionStylePartialCurl on

Question

In Apple's official Maps app for the iPhone, there is a small 'page curl' button in the lower-right corner. When you press it, the map itself peels back to reveal some options. I would like to duplicate this effect in my own app.

I'm trying to use UIModalTransitionStylePartialCurl (Added in SDK 3.2). In terms of its layout, my app resembles Apple's official Maps app almost exactly. I can easily get the ENTIRE screen to peel back, revealing another view underneath, but I don't want this. I want ONLY the map view to peel back.

In order to create this effect, you must have a UIViewController that will perform the transition. If I set this UIViewController's view to a small subview somewhere on the screen that does not take up the entire screen, I can get just that subview to peel back. That's great! However, after the second part of the transition (when the page falls back into place), the views are never where they started. Either the view that peeled back will have moved from its original position, or the view that was revealed will have expanded to take up the entire screen.

Is there any obvious mistake that I'm making? I would really appreciate any help!

The code I'm using is really simple. It's basically just:

underMapViewController.modalTransitionStyle = UIModalTransitionStylePartialCurl;

[curlableMapViewController presentModalViewController:underMapViewController animated:YES];

Answer 1

How about something like this:

    [UIView beginAnimations:@"PartialPageCurlEffect" context:nil];
    [UIView setAnimationDuration:0.3];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
    [UIView setAnimationTransition:UIViewAnimationTransitionCurlUp forView:myOldSubViewController.view cache:YES];

    [myOldSubViewController.view addSubview:myNewViewController.view];

    [UIView commitAnimations];

Note: for some views if the views are complex and off-centre there could be artifacts. Changing cache:YES to cache:NO may fix with.

Answer 2

I had a slight hiccough confusing

.modalTransitionStyle

and

.modalPresentationStyle

The first one goes on the TARGET viewController, e.g., the one you want underneath. The second goes on the PARENT viewController, e.g. the one that actually gets distorted by the curl. The OP got this right, but I got it wrong, and it was a frustrating 10 minutes before I figured it out. Throwing it on this post in case it gives someone else the head slap I needed.