[self.navigationController popToViewController:VC2 animated:NO]; 紧急

Question

嗨,我正在开发一个我应该去的应用程序:

1. 从UIViewController1到UIViewController2
2. 从UIViewController2到UIViewController3
3. 从UIViewController3到UIViewController4
4. 从UIViewController4回到UIViewController2

我在用UINavigationController.当我使用[self.navigationController pushViewController:VC2 animated:NO];,[self.navigationController popViewControllerAnimated:NO];一切正常.

但是当我使用[self.navigationController popToViewController:VC2 animated:NO];从UIViewController4应用程序终止说法Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Tried to pop to a view controller that doesn't exist.'

以下是我的代码如何弹出UIViewController2

for (UIViewController *vc in self.navigationController.viewControllers) {
            if ([vc isKindOfClass:[ViewController2 class]]) {
                UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle: nil];
                ViewController2 *VC2 = [storyboard instantiateViewControllerWithIdentifier:@"ViewController2"];
                [self.navigationController popToViewController:VC2 animated:NO];
            }
        }

当我打印导航阵列时,它显示UIViewController2个堆栈.我已经UINavigationController从Editor-> embed in-> Navigation Controller添加了

谁能告诉我为什么会这样？我试图搜索这个问题,但没有任何帮助

Answer 1

在这里,您实例化一个新的VC2视图控制器实例,这不是导航视图控制器堆栈上的实例!

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle: nil];
            ViewController2 *VC2 = [storyboard     instantiateViewControllerWithIdentifier:@"ViewController2"];

所以你必须找到正确的实例

[[self.navigationController] viewControllers]

解决方案1 ​​:(正如iDev所说,跳转到堆栈上的第二个视图控制器,如果你知道它是第二个,请使用它)

[self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:1] animated:YES];

解决方案2 :(通常在堆栈上返回2级)

NSUInteger ownIndex = [self.navigationController.viewControllers indexOfObject:self];
[self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:ownIndex - 2] animated:YES];

Answer 2

那是你的代码:

for (UIViewController *vc in self.navigationController.viewControllers) {
    if ([vc isKindOfClass:[ViewController2 class]]) {
        UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle: nil];
        ViewController2 *VC2 = [storyboard instantiateViewControllerWithIdentifier:@"ViewController2"];
        [self.navigationController popToViewController:VC2 animated:NO];
    }
}

你可能已经发现的vc是一种ViewController2,那就是已经在导航堆栈.新实例,您创建为VC2的ViewController2,是不是在导航栈,它永远不会是.

看到例外的正文:

由于未捕获的异常'NSInternalInconsistencyException'而终止应用程序,原因:'尝试弹出到不存在的视图控制器.

因此,您想要导航回未进入导航堆栈的视图控制器 - 这会导致崩溃.

你必须导航回已经在堆栈中的视图控制器- 这是你的vc:

for (UIViewController *vc in self.navigationController.viewControllers) {
    if ([vc isKindOfClass:[ViewController2 class]]) {
        [self.navigationController popToViewController:vc animated:NO];
    }
}

Answer 3

尝试使用此行将viewcontroller弹出到第2行

  [self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:1] animated:YES];