如何检查 uiviewcontroller 是否存在于 uinavigationcontroller 堆栈中 [英] How to check a uiviewcontroller is present in uinavigationcontroller stack

问题描述

我有一个 UINavigationController.我必须从 UINavigationController 弹出一个视图并将其替换为另一个视图.我们如何搜索 UIViewController 对象并将其替换为另一个对象?

I have a UINavigationController. I have to pop a view from a UINavigationController and replace it with another view. How we can search for a UIViewController object and replace it with another ?

当我打印时

NSMutableArray *allViewControllers = [NSMutableArray arrayWithArray:           myDelegate.navigationController.viewControllers];

我试过了..

[allViewControllers removeObjectIdenticalTo: @"NonLogginedViewController"];         
[allViewControllers removeObjectIdenticalTo: myDelegate.nonLogginedViewController];
myDelegate.navigationController.viewControllers = allViewControllers;

但它没有更新 UINavigationController 堆栈..我不知道如何将 removeObjectIdenticalTo 与 UINavigationController 堆栈一起使用..

But it didn't update the UINavigationController stack .. I don't know how to use removeObjectIdenticalTo with UINavigationController stack..

请帮帮我..

推荐答案

首先，你的测试:

Firstly, your test:

[allViewControllers removeObjectIdenticalTo:@"NonLogginedViewController"];

[allViewControllers removeObjectIdenticalTo: @"NonLogginedViewController"];

...正在测试字符串，而不是视图控制器.所以这行不通.

...is testing for a string, not a view controller. So that won't work.

如果您知道视图控制器在导航控制器堆栈中的位置，那么这很容易.例如，您刚刚推送了一个新控制器，现在您想删除之前的控制器.你可以这样做:

If you know where the view controller is in the navigation controller's stack then this is easy. Say for example you've just pushed a new controller and now you want to remove the one before that. You could do this:

NSMutableArray *allControllers = [self.navigationController.viewControllers mutableCopy];
[allControllers removeObjectAtIndex:allControllers.count - 2];
[self.navigationController setViewControllers:allControllers animated:NO];

但我认为在您的情况下，您想找到某个控制器并将其删除.一种方法是寻找某个类，例如登录控制器.通过复制旧数组来设置一个新数组，然后遍历这个新数组:

But I think in your case you want to find a certain controller and remove it. One way to do this would be to look for a certain class, e.g. LoginController. Set up a new array by copying the old one, and then iterate through this new array:

NSArray *allControllersCopy = [allControllers copy];

for (id object in allControllersCopy) {
   if ([object isKindOfClass:[LoginController class]])
      [allControllers removeObject:object];
}

...然后像以前一样为 viewControllers 属性设置 allControllers 数组.

...then set the allControllers array for the viewControllers property, as before.

注意:如果您从包含视图控制器操作 UINavigationController 的堆栈——也许一旦该视图控制器出现——你应该等到视图完全显示在屏幕上.一个很好的地方是在 viewDidAppear: 覆盖，例如:

NOTE: If you're manipulating a UINavigationController's stack from a containing view controller – perhaps once that view controller appears – you should wait until the view is fully onscreen. A good place for that is in the viewDidAppear: override, for example:

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated]; 
    NSMutableArray *allControllers = ...
}

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