iOS：目前是否有办法阻止同时推送或弹出两个视图控制器？(iOS: Is there currently a way to prevent two view controllers being pus

iOS：目前是否有办法阻止同时推送或弹出两个视图控制器？(iOS: Is there currently a way to prevent two view controllers being pushed or popped at the same time?)

我见过的唯一解决方案是回答stackoverflow问题。我发布了以下链接。我所指的答案是第五个。但是，似乎有些用户在使用该解决方案时遇到了一些问题。我不知道是否有另一个类别可以防止同时推送两个控制器。任何提示或建议表示赞赏。

#import "UINavigationController+Consistent.h" #import <objc/runtime.h> /// This char is used to add storage for the isPushingViewController property. static char const * const ObjectTagKey = "ObjectTag"; @interface UINavigationController () @property (readwrite,getter = isViewTransitionInProgress) BOOL viewTransitionInProgress; @end @implementation UINavigationController (Consistent) - (void)setViewTransitionInProgress:(BOOL)property { NSNumber *number = [NSNumber numberWithBool:property]; objc_setAssociatedObject(self, ObjectTagKey, number , OBJC_ASSOCIATION_RETAIN); } - (BOOL)isViewTransitionInProgress { NSNumber *number = objc_getAssociatedObject(self, ObjectTagKey); return [number boolValue]; } #pragma mark - Intercept Pop, Push, PopToRootVC /// @name Intercept Pop, Push, PopToRootVC - (NSArray *)safePopToRootViewControllerAnimated:(BOOL)animated { if (self.viewTransitionInProgress) return nil; if (animated) { self.viewTransitionInProgress = YES; } //-- This is not a recursion, due to method swizzling the call below calls the original method. return [self safePopToRootViewControllerAnimated:animated]; } - (NSArray *)safePopToViewController:(UIViewController *)viewController animated:(BOOL)animated { if (self.viewTransitionInProgress) return nil; if (animated) { self.viewTransitionInProgress = YES; } //-- This is not a recursion, due to method swizzling the call below calls the original method. return [self safePopToViewController:viewController animated:animated]; } - (UIViewController *)safePopViewControllerAnimated:(BOOL)animated { if (self.viewTransitionInProgress) return nil; if (animated) { self.viewTransitionInProgress = YES; } //-- This is not a recursion, due to method swizzling the call below calls the original method. return [self safePopViewControllerAnimated:animated]; } - (void)safePushViewController:(UIViewController *)viewController animated:(BOOL)animated { self.delegate = self; //-- If we are already pushing a view controller, we dont push another one. if (self.isViewTransitionInProgress == NO) { //-- This is not a recursion, due to method swizzling the call below calls the original method. [self safePushViewController:viewController animated:animated]; if (animated) { self.viewTransitionInProgress = YES; } } } // This is confirmed to be App Store safe. // If you feel uncomfortable to use Private API, you could also use the delegate method navigationController:didShowViewController:animated:. - (void)safeDidShowViewController:(UIViewController *)viewController animated:(BOOL)animated { //-- This is not a recursion. Due to method swizzling this is calling the original method. [self safeDidShowViewController:viewController animated:animated]; self.viewTransitionInProgress = NO; } // If the user doesnt complete the swipe-to-go-back gesture, we need to intercept it and set the flag to NO again. - (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated { id<UIViewControllerTransitionCoordinator> tc = navigationController.topViewController.transitionCoordinator; [tc notifyWhenInteractionEndsUsingBlock:^(id<UIViewControllerTransitionCoordinatorContext> context) { self.viewTransitionInProgress = NO; //--Reenable swipe back gesture. self.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>)viewController; [self.interactivePopGestureRecognizer setEnabled:YES]; }]; //-- Method swizzling wont work in the case of a delegate so: //-- forward this method to the original delegate if there is one different than ourselves. if (navigationController.delegate != self) { [navigationController.delegate navigationController:navigationController willShowViewController:viewController animated:animated]; } } + (void)load { //-- Exchange the original implementation with our custom one. method_exchangeImplementations(class_getInstanceMethod(self, @selector(pushViewController:animated:)), class_getInstanceMethod(self, @selector(safePushViewController:animated:))); method_exchangeImplementations(class_getInstanceMethod(self, @selector(didShowViewController:animated:)), class_getInstanceMethod(self, @selector(safeDidShowViewController:animated:))); method_exchangeImplementations(class_getInstanceMethod(self, @selector(popViewControllerAnimated:)), class_getInstanceMethod(self, @selector(safePopViewControllerAnimated:))); method_exchangeImplementations(class_getInstanceMethod(self, @selector(popToRootViewControllerAnimated:)), class_getInstanceMethod(self, @selector(safePopToRootViewControllerAnimated:))); method_exchangeImplementations(class_getInstanceMethod(self, @selector(popToViewController:animated:)), class_getInstanceMethod(self, @selector(safePopToViewController:animated:))); } @end

iOS应用程序错误 - 无法将self添加为子视图

The only solution I have seen was an answer to a stackoverflow question. I posted the link below. The answer I am referring is the 5th one. It seems that some users have some problems with the solution however. I don't know if there is another category to prevent two controllers from being pushed at the same time. Any tips or suggestions are appreciated.

iOS app error - Can't add self as subview

最满意答案

更新的答案：

我更喜欢Github上的nonamelive解决方案，我最初发布的内容： https ： nonamelive 。通过UINavigationController并利用UINavigationControllerDelegate ，您可以确定转换何时发生，防止在转换期间发生其他转换，并在同一个类中完成所有转换。这是nonamelive解决方案的更新，它排除了私有API：

#import "NavController.h" @interface NavController () @property (nonatomic, assign) BOOL shouldIgnorePushingViewControllers; @end @implementation NavController - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view. } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } - (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated { if (!self.shouldIgnorePushingViewControllers) { [super pushViewController:viewController animated:animated]; } self.shouldIgnorePushingViewControllers = YES; } - (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated { self.shouldIgnorePushingViewControllers = NO; } @end

上一个答案：

这个问题以前的答案： isBeingPresented和isBeingDismissed仅适用于viewDidLoad:或viewDidApper:

虽然我自己没有测试过，但这是一个建议。

由于您使用的是UINavigationController ，因此可以访问导航堆栈的内容，如下所示：

NSArray *viewControllers = self.navigationController.viewControllers;

通过该视图控制器数组，您可以根据需要访问部分或全部相关索引。

幸运的是，iOS 5中引入了两种特别方便的方法： isBeingPresented和isBeingDismissed ，如果视图控制器分别处于呈现或被解除的过程中，则返回“YES”; 否则“不”。

所以，例如，这是一种方法：

NSArray *viewControllers = self.navigationController.viewControllers; for (UIViewController *viewController in viewControllers) { if (viewController.isBeingPresented || viewController.isBeingDismissed) { // In this case when a pop or push is already in progress, don't perform // a pop or push on the current view controller. Perhaps return to this // method after a delay to check this conditional again. return; } } // Else if you make it through the loop uninterrupted, perform push or pop // of the current view controller.

实际上，您可能不必遍历堆栈中的每个视图控制器，但是这个建议可能会帮助您摆脱困境。

Updated answer:

I prefer this solution by nonamelive on Github to what I originally posted: https://gist.github.com/nonamelive/9334458. By subclassing the UINavigationController and taking advantage of the UINavigationControllerDelegate, you can establish when a transition is happening, prevent other transitions from happening during that transition, and do so all within the same class. Here's an update of nonamelive's solution which excludes the private API:

Previous answer:

Problem with this Previous Answer: isBeingPresented and isBeingDismissed only work in viewDidLoad: or viewDidApper:

Although I haven't tested this myself, here is a suggestion.

Since you're using a UINavigationController, you can access the contents of your navigation stack, like so:

NSArray *viewControllers = self.navigationController.viewControllers;

And through that array of view controllers, you can access some or all relevant indices if need be.

Luckily, two especially convenient methods were introduced in iOS 5: isBeingPresented and isBeingDismissed which return "YES" if the view controller is in the process of being presented or being dismissed, respectively; "NO" otherwise.

So, for example, here's one approach:

In actuality, you probably won't have to loop through every view controller on the stack, but perhaps this suggestion will help set you off on the right foot.

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