How to check if a view controller is presented modally or pushed on a navigation stack?

Question

How can I, in my view controller code, differentiate between:

• presented modally
• pushed on navigation stack

Both presentingViewController and isMovingToParentViewController are YES in both cases, so are not very helpful.

What complicates things is that my parent view controller is sometimes modal, on which the to be checked view controller is pushed.

It turns out my issue is that I embed my HtmlViewController in a UINavigationController which is then presented. That's why my own attempts and the good answers below were not working.

HtmlViewController*     termsViewController = [[HtmlViewController alloc] initWithDictionary:dictionary];
UINavigationController* modalViewController;

modalViewController = [[UINavigationController alloc] initWithRootViewController:termsViewController];
modalViewController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentViewController:modalViewController
                   animated:YES
                 completion:nil];

I guess I'd better tell my view controller when it's modal, instead of trying to determine.

Solution 1

Take with a grain of salt, didn't test.

- (BOOL)isModal {
     if([self presentingViewController])
         return YES;
     if([[[self navigationController] presentingViewController] presentedViewController] == [self navigationController])
         return YES;
     if([[[self tabBarController] presentingViewController] isKindOfClass:[UITabBarController class]])
         return YES;

    return NO;
 }

Solution 2

In Swift:

Add a flag to test if it's a modal by the class type:

// MARK: - UIViewController implementation

extension UIViewController {

    var isModal: Bool {

        let presentingIsModal = presentingViewController != nil
        let presentingIsNavigation = navigationController?.presentingViewController?.presentedViewController == navigationController
        let presentingIsTabBar = tabBarController?.presentingViewController is UITabBarController

        return presentingIsModal || presentingIsNavigation || presentingIsTabBar
    }
}

Solution 3

You overlooked one method: isBeingPresented.

isBeingPresented is true when the view controller is being presented and false when being pushed.

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    if ([self isBeingPresented]) {
        // being presented
    } else if ([self isMovingToParentViewController]) {
        // being pushed
    } else {
        // simply showing again because another VC was dismissed
    }
}

Solution 4

Swift 5
Here is solution that addresses the issue mentioned with previous answers, when isModal() returns true if pushed UIViewController is in a presented UINavigationController stack.

extension UIViewController {
    var isModal: Bool {
        if let index = navigationController?.viewControllers.firstIndex(of: self), index > 0 {
            return false
        } else if presentingViewController != nil {
            return true
        } else if navigationController?.presentingViewController?.presentedViewController == navigationController {
            return true
        } else if tabBarController?.presentingViewController is UITabBarController {
            return true
        } else {
            return false
        }
    }
}

It does work for me so far. If some optimizations, please share.

Solution 5

self.navigationController != nil would mean it's in a navigation stack.

In order to handle the case that the current view controller is pushed while the navigation controller is presented modally, I have added some lines of code to check if the current view controller is the root controller in the navigation stack .

extension UIViewController {
    var isModal: Bool {
        if let index = navigationController?.viewControllers.firstIndex(of: self), index > 0 {
            return false
        } else if presentingViewController != nil {
            return true
        } else if let navigationController = navigationController, navigationController.presentingViewController?.presentedViewController == navigationController {
            return true
        } else if let tabBarController = tabBarController, tabBarController.presentingViewController is UITabBarController {
            return true
        } else {
            return false
        }
    }
}

View more solutions

Comments

[ColdLogic]

Can still be in a modal navigation controller

[JRG-Developer]

+1: Nice approach. :D This assumes, of course, that you care that presentingViewController's presentedViewController must match self (and not simply be an ancestor).

[meaning-matters]

I found this in another SO post. But, does not work if the pushed view controller's parent is a modal; which is the situation I'm having.

[ColdLogic]

added if([self presentingViewController]) return YES;

[ColdLogic]

If presentingViewController is not nil, then either you or an ancestor is being presented modally.

[meaning-matters]

As I wrote, presentingViewController is always YES in my case; does not help.

[ColdLogic]

What do you mean it doesn't work then? Is it returning yes when you expect it to return no?

[meaning-matters]

I tried this too before posting, and it does not work, isBeingPresented is NO. But I see the reason now, I'm embedding my presented view controller in a UINavigationController, and that's the one I'm pushing.

[A . Radej]

So 'modal' and 'pushed on navigation stack' are not mutually exclusive. Thinking this depends on the context, but checking if self.navigationController is not nil does answer whether it's a view controller of a navigation controller.

[meaning-matters]

See edits, I was embedding my view controller in a navigation controller, so all these methods were not working. Since you were the first with a in principle good answer you won all the points.

[rmaddy]

You can't push a navigation controller. Perhaps you meant that you are presenting the navigation controller.

[rmaddy]

@Daniel The difference is between "pushed" and "presented". "Modal' has nothing to do with it. I believe "ColdLogic" meant "presented" when they said "modal".

[Yevhen Dubinin]

presentingViewController returns YES for pushed VC, when there is a UITabBarController being set as a root. So, does not suitable in my case.

[jowie]

For some reason, self.isBeingPresented is always nil for me. I've had to use self.presentingViewController. I have no idea why.

[Admin]

@jowie: Please be aware of the method definition, it returns a BOOL, not an NSObject => - (BOOL)isBeingPresented NS_AVAILABLE_IOS(5_0);

[jowie]

@SebastianKeller yes I know, but po self.isBeingPresented shouldn't return nil. If I test on other projects and different view controllers, the result of that statement is false. My project is iOS 8.1 and above.

[rmaddy]

@jowie Use p, not po when printing a primitive value. po is for printing objects.

[Morkrom]

This property is deprecated.

[funct7]

Documentation for isBeingPresented - This method returns YES only when called from inside the viewWillAppear: and viewDidAppear: methods.

[Lee]

This does not work if you present a view controller then it pushes another one.

[meaning-matters]

Yes, I meant that I present the UINavigationController.

[Terrence]

@BridgeTheGap What documentation are you referring to? I don't see this in the UIViewController Overview nor on the property reference itself.

[rmaddy]

@Terrence It seems the latest documentation doesn't show that information but it used to be there. The isBeingPresented, isBeingDismissed, isMovingFromParentViewController and isMovingToParentViewController are only valid inside the 4 view[Will|Did][Disa|A]ppear methods.

[Alexander Abakumov]

which you should always do anyway - please explain why?

[E-Riddie]

Well in general when you present modally, you put the viewController on a navigationController and you present it. If that is the case your statement would be wrong, however on the code this case is handled. Please improve your answer :)

[Colin Swelin]

"This does not work if you present a view controller then it pushes another one" That's not the intention of this, the pushed view controller isn't being presented.

[nickdnk]

Alexander, you shouldn't, really.

[jk7]

isBeingPresented works in other situations but seems to give inconsistent results. Ex. After presenting a popover from within the UITextFieldDelegate method, textField:shouldChangeCharactersInRange:replacementString:, isBeingPresented correctly returned YES while still within the scope of that method call, but the next time that method was called it return NO even though the popover was still being presented.

[malinois]

Should be better in a var, like var isModal: Bool {}

[Eli Burke]

Swift 4.2 / iOS 12. Still works well, but be aware that navigationController?.presentingViewController?.presentedVie‌​wController === navigationController will evaluate to true if both are nil (for example, if you call it on a view controller that has not yet been presented).

[YannSteph]

@malinois is changed

[Cesare]

Upvoted but didn't work on my end. I'm presenting a view controller modally but it returns false. Not sure why.

[gklka]

This method does not work when you use same view controller class in multiple places, since it does check only the class of it. You can explicitly check the equality instead.

[damjandd]

What does the last false parameter in the return statement do?

[Jean Raymond Daher]

good job that deals with all the use cases. room for a bit of refactoring probably but still upvote !!

[Hlung]

Why do you need to check tabBarController?.presentingViewController is UITabBarController ? Does it matter if that presentingViewController is also a UITabBarController?

[Hlung]

And if navigationController is nil, isModal will return true. Is this intended?

[famfamfam]

you need change to let presentingIsNavigation = navigationController?.presentingViewController?.presentedVie‌​wController == navigationController && navigationController != nil

[Tà Truhoada]

Swift 5: presentingIsNavigation = true if navigationController is nil

[meaning-matters]

Thanks for this answer. I'll try to find time to check this. BTW, I think it's semantically better to put the second return statement in an else { } block because it's the opposite case of having a navigation controller.