iPhone UINavigation Issue - nested push animation

Question

I keep getting the following errors:

2011-04-02 14:55:23.350 AppName[42430:207] nested push animation can result in corrupted navigation bar
2011-04-02 14:55:23.352 AppName[42430:207] nested push animation can result in corrupted navigation bar
2011-04-02 14:55:23.729 AppName[42430:207] Finishing up a navigation transition in an unexpected state. Navigation Bar subview tree might get corrupted.
2011-04-02 14:55:23.729 AppName[42430:207] Finishing up a navigation transition in an unexpected state. Navigation Bar subview tree might get corrupted.

Here is what I am doing. From a view controller, I call the following when a certain button is pushed:

EventsViewController *viewController = [[EventsViewController alloc] init];
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:viewController];
navController.navigationBar.tintColor = [UIColor blackColor];
[self presentModalViewController:navController animated:YES];
[viewController release];
[navController release];

Then, if a certain button is pushed in EventsController, I call:

SingleEventViewController *viewController = [[SingleEventViewController alloc] initWithEvent:[currentEvents objectAtIndex:indexPath.row]];
[self.navigationController pushViewController:viewController animated:YES];
[viewController release];

Then, if a certain button is pushed in SingleEventViewController, I call:

EventMapView* viewController = [[EventMapView alloc] initWithCoordinates];
[[self navigationController] pushViewController:viewController animated:YES];
[viewController release];

So yea, it's obvious that there's nested push animations, but isn't this the right way to go about it? I checked out Apple's DrillDownSave code and this appears to be how they're doing it. Does it matter that I use init methods instead of viewDidLoad methods?

Answer 1

1) Perhaps you could try passing the necessary variables as properties before pushing the UIViewController rather than using the init methods with parameters. Most likely you will need these parameters beyond your init method anyway.

Also, in your initWithCoordinates: method you are missing the parameters. Possibly your custom init methods are a part of the problem.

2) Just because you mentioned viewDidLoad -- this method is for initialization after a view has loaded . If you create the UIViewController in code, as it seems you do, you should use loadView to set up your subviews.

Answer 2

This has already been answered, but I thought this might help others as I got the same error but without using table views. I finally figured out the problem.

I had an existing button whose IBAction invoked a pushViewController. I had created a new button by copying the existing button. The new button also had an action that invoked pushViewController. When the new button was tapped (touch up inside) and the view controller was pushed, I got this error. I deleted the new button, created it from scratch, bound it to the existing outlets and actions, and the error went away.

Answer 3

My Solution was

[self performSelector:@selector(moveTo) withObject:nil afterDelay:0.5];

Answer 4

This resolves the problem: https://github.com/nexuspod/SafeTransition

If you push (or pop) a view controller with animation(animated:YES) it doesn't complete right away, and bad things happen if you do another push or pop before the animation completes.

To reproduce this bug, try pushing or popping two view controllers at the same time. Example:

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    UIViewController *vc = [[UIViewController alloc] init];
    [self.navigationController pushViewController:vc animated:YES];
}

You will receive this error:

2014-07-03 11:54:25.051 Demo[2840:60b] nested push animation can result in corrupted navigation bar 2014-07-03 11:54:25.406 Demo[2840:60b] Finishing up a navigation transition in an unexpected state. Navigation Bar subview tree might get corrupted.

Just add the code files into your project and makes your navigation controller as a subclass of APBaseNavigationController, and you'll be good to do.

Answer 5

What do you mean when you say you use init methods instead of viewDidLoad methods?

If you're pushing a new view controller before the old push has bad a chance to be actioned, you will get this sort of error. So putting certain code into init and doing things prematurely could certainly get you the error being reported.

At the point where init is being run on a view controller, the view hasn't been loaded yet!

Answer 6

I've figured it out. Apparently if you call -pushViewController from outside of the -didSelectRowAtIndexPath method of a UITableViewDelegate, it doesn't work. Moving the call into that function worked. Weird.