“应用程序试图提供模态主动控制器”？

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".

Just remove

[tabBarController presentModalViewController:viewController animated:YES];

and keep

[self dismissModalViewControllerAnimated:YES];

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

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

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

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.

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

Instead of using:

self.present(viewControllerToPresent: UIViewController, animated: Bool, completion: (() -> Void)?)

you can use:

self.navigationController?.pushViewController(viewController: UIViewController, animated: Bool)

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

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

This is my way which supporting multiple Windows(from a single APP) on the iPad and nested modal present.

import UIKit


///✅Use this public method
public func SheetViewController(ViewController:UIViewController) {
    

for i in returnAvailableViewControllers().shuffled() {
if i.presentedViewController == nil && !ViewController.isViewLoaded {i.present(ViewController, animated: true, completion:  {})}
}
}


///Returns all possible ViewControllers
private func returnAvailableViewControllers() -> [UIViewController] {
let 场景 = UIApplication.shared.connectedScenes
    

var 存储VC : [UIViewController] = []


for i in 场景 {
        

if i.activationState == .foregroundActive {
//⭐️Set up “foregroundActive” to give the user more control
var 视图控制器 = (i.delegate as? UIWindowSceneDelegate)?.window??.rootViewController
            

if 视图控制器 != nil {
存储VC.append(视图控制器!)
}
            

            

            

var 结束没 = true
while 结束没 {
//🌟Enumerate all child ViewController
视图控制器 = 视图控制器?.presentedViewController
if 视图控制器 != nil {
存储VC.append(视图控制器!)
} else {
结束没.toggle()
}
}
}
        

        

}
return 存储VC
}