Custom animation for pushing a UIViewController

Question

Hi,

I want to show a custom animation when pushing a view controller: I would like to achieve something like an "expand" animation, that means the new view expands from a given rectangle, lets say [100,100 220,380] during the animation to full screen.

Any suggestions where to start, respectively any documents, tutorials, links? :)

heinrich

Answer 1

What you want is the downloads for chapter 2 of iphone developers cookbook. Look at the affineRotate sample specifically, although any of the core animatin samples will help you.

Answer 2

In the sample code, a function is called all 0.03 seconds that updates the transformation of the view. Unfortunately, when pushing a UIViewController, I am not able to resize the frame of the view ... am I ?

Answer 3

Alright. I could make the expand animation with the following code:

if ([coming.view superview] == nil)
[self.view addSubview:coming.view]; coming.view.frame = CGRectMake(160,160,0,0); [UIView beginAnimations:@"frame" context:nil]; [UIView setAnimationDuration:4]; [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut]; [coming viewWillAppear:YES]; [going viewWillAppear:YES]; coming.view.frame = CGRectMake(0, 0, 320, 480); [going viewDidDisappear:YES]; [coming viewDidAppear:YES]; [UIView commitAnimations];

My View is properly displayed, but unfortunately the navigation bar is not updatet. Is there a way to do that manually?

heinrich

Answer 4

What you could do is push the next view controller but don't animate it, like so:

[self.navigationController pushViewController:nextController animated:NO];

...and then, in the view controller that is getting pushed in, you could do a custom animation of it's view using CoreAnimation. This might be best done in the viewDidAppear:(BOOL)animated method.

Check out the Core Animation Guide on how to actually do the animation. Look particularly at the implicit animation.

Answer 5

I use the following function (added to UINavigationController) to customize the push animation:

- (void) pushController: (UIViewController*) controller
         withTransition: (UIViewAnimationTransition) transition
{
    [UIView beginAnimations:nil context:NULL];
    [self pushViewController:controller animated:NO];
    [UIView setAnimationDuration:.5];
    [UIView setAnimationBeginsFromCurrentState:YES];        
    [UIView setAnimationTransition:transition forView:self.view cache:YES];
    [UIView commitAnimations];
}

I guess you could adapt this code to do whatever animation you want.

Answer 6

@zoul: That worked great! I just changed "self" to "self.navigationController" and "self.view" to "self.navigationController.view" Don't know if that was necessary, but it worked. And @crafterm, as for popping back, just make your own leftBarButtonItem by adding this code in viewDidLoad or ViewWillAppear:

    //add your own left bar button
UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStylePlain target:self action:@selector(backButtonTapped)];
self.navigationItem.leftBarButtonItem = backButton;
[backButton release];

Then I just tweaked the push function and made this popWithTransition function that I called in my -backButtonTapped method.

- (void) popWithTransition: (UIViewAnimationTransition) transition

{ [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:.75]; [UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationTransition:transition forView:self.navigationController.view cache:YES]; [UIView commitAnimations]; [self.navigationController popViewControllerAnimated:NO];

}

Note that the popViewController call got shifted down to the end, after the animation. Don't know if that's kosher, but again, it worked.

Answer 7

Heinrich,

I have made a youtube tutorial showing how to make views expand and shrink, like in the facebook iPhone app.

Hope it can be of help: How to make expanding/shrinking views on iPhone SDK

Adam

Answer 8

This code is what are you looking for:

    [UIView beginAnimations:@"View Flip" context:nil];
[UIView setAnimationDuration:0.80];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];

[UIView setAnimationTransition:
 UIViewAnimationTransitionFlipFromRight
                       forView:self.navigationController.view cache:NO];


[self.navigationController pushViewController:menu animated:YES];
[UIView commitAnimations];