Change interactivePopGestureRecognizer direction

Question

My app supports both English and Arabic. interactivePopGestureRecognizer works properly when using English, ie on swiping from left to right, it pops viewController. But when i am using arabic, I have changed the semanticContentAttribute from right to left.

if([[[NSUserDefaults standardUserDefaults] objectForKey:@"LanguageCode"] isEqualToString:@"en"])
    {
        [[UIView appearance] setSemanticContentAttribute:UISemanticContentAttributeForceLeftToRight];       //View for English language
    }
    else
    {
        [[UIView appearance] setSemanticContentAttribute:UISemanticContentAttributeForceRightToLeft];       //mirror view for Arabic language
    }

But the interactivePopGestureRecogniser is still from left to right. How can I change the direction of interactivePopGestureRecogniser such that it supports Arabic? I want to swipe from right to left to pop view controller on using Arabic language.

Answer 1

I found the solution for it after searching long time, if someone seeks.

The previous answer may cause the UI to hang / freeze.

The reason that the UI freezes / hangs is because the UINavigationController is missing a check for the root view controller when the gesture is executed on the root view. There a few ways to fix that, the following is what I did.

You should subclass UINavigationController, this is the right way to go and add implement as followed:

class RTLNavController: UINavigationController, UINavigationControllerDelegate, UIGestureRecognizerDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        //  Adding swipe to pop viewController
        self.interactivePopGestureRecognizer?.isEnabled = true
        self.interactivePopGestureRecognizer?.delegate = self

        //  UINavigationControllerDelegate
        self.delegate = self
    }
    
    func navigationController(_ navigationController: UINavigationController, willShow viewController: UIViewController, animated: Bool) {
        navigationController.view.semanticContentAttribute = UIView.isRightToLeft() ? .forceRightToLeft : .forceLeftToRight
        navigationController.navigationBar.semanticContentAttribute = UIView.isRightToLeft() ? .forceRightToLeft : .forceLeftToRight
    }

    //  Checking if the viewController is last, if not disable the gesture
    func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        if self.viewControllers.count > 1 {
            return true
        }
        
        return false
    }
}

extension UIView {
    static func isRightToLeft() -> Bool {
        return UIView.appearance().semanticContentAttribute == .forceRightToLeft
    }
}

Resources:

Original question:

• Slide gesture with custom back button freezes the root view controller

The answer is used for the solution:

• https://stackoverflow.com/a/27683249/1138498

Other solution which may work better (But it's in Objective-C):

• https://stackoverflow.com/a/28364126/1138498

Answer 2

After a lot of trials, the only solution worked for me was this:

Swift 3:

extension UIViewController {
    open override func awakeFromNib() {
        super.awakeFromNib()
        navigationController?.view.semanticContentAttribute = .forceRightToLeft
        navigationController?.navigationBar.semanticContentAttribute = .forceRightToLeft
    }
}

You can exclude the semantic attribute for certain types like:

UIView.appearance(whenContainedInInstancesOf: [UITableViewCell.self]).semanticContentAttribute = .forceLeftToRight