"Application tried to present modally an active controller"?

Question

I just came across a crash showing a NSInvalidArgumentException with this message on an app which wasn't doing this before.

Application tried to present modally an active controller UITabBarController: 0x83d7f00.

I have a UITabBarController which I create in the AppDelegate and give it the array of UIViewControllers.

One of them I want to present modally when tapped on it. I did that by implementing the delegate method

- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController

If that view controller is of the class of the one I want to present modally, I return NO and do

[tabBarController presentModalViewController:viewController animated:YES];

And now I'm getting that error, which seems to mean that you can't present modally a view controller that is active somewhere else (in the tabbar...) I should say I'm on XCode 4.2 Developer Preview 7, so this is iOS 5 (I know about the NDA, but I think I'm not giving any forbidden details). I currently don't have an XCode installation to test if this crashes compiling against the iOS4 SDK, but I'm almost entirely sure it doesn't.

I only wanted to ask if anyone has experienced this issue or has any suggestion

Answer 1

Assume you have three view controllers instantiated like so:

UIViewController* vc1 = [[UIViewController alloc] init];
UIViewController* vc2 = [[UIViewController alloc] init];
UIViewController* vc3 = [[UIViewController alloc] init];

You have added them to a tab bar like this:

UITabBarController* tabBarController = [[UITabBarController alloc] init];
[tabBarController setViewControllers:[NSArray arrayWithObjects:vc1, vc2, vc3, nil]];

Now you are trying to do something like this:

[tabBarController presentModalViewController:vc3];

This will give you an error because that Tab Bar Controller has a death grip on the view controller that you gave it. You can either not add it to the array of view controllers on the tab bar, or you can not present it modally.

Apple expects you to treat their UI elements in a certain way. This is probably buried in the Human Interface Guidelines somewhere as a "don't do this because we aren't expecting you to ever want to do this".

Answer 2

I have the same problem. I try to present view controller just after dismissing.

[self dismissModalViewControllerAnimated:YES];

When I try to do it without animation it works perfectly so the problem is that controller is still alive. I think that the best solution is to use dismissViewControllerAnimated:completion: for iOS5

Answer 3

In my case i was trying to present the viewController (i have the reference of the viewController in the TabBarViewController) from different view controllers and it was crashing with the above message. In that case to avoid presenting you can use

viewController.isBeingPresented

!viewController.isBeingPresented {
          // Present your ViewController only if its not present to the user currently.
}

Might help someone.

Answer 4

The same problem error happened to me when I tried to present a child view controller instead of its UINavigationViewController parent

Answer 5

I had same problem.I solve it. You can try This code:

[tabBarController setSelectedIndex:1];
[self dismissModalViewControllerAnimated:YES];

Answer 6

For React Native Developer - Problem might not be in AppDelegate Or main.m if app has been successfully build and is running and will crash after splash or perhaps the error screen

Issue might be due to use of fonts/resources that is not available with xcode and not properly configured.. You can find out the error by commenting certain portion starting from App.js and drilling inside the navigation/screens and commenting the components till you find the component that is generating the error....

In my case the resource of fontFamily was making an issue which was used right after splash in walkthrough screen

<Text style={{fontFamily: Fonts.roboto}}>ABC</Text>

Here font roboto wasnot configured properly. Wasted entire days just debugging the error hope its helps you

Answer 7

In my case, I was presenting the rootViewController of an UINavigationController when I was supposed to present the UINavigationController itself.