ios - [self.navigationController popToViewController :VC2 animated:NO]; crash

Question

您好，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

我正在使用 UINavigationController。当我使用 [self.navigationController pushViewController:VC2 animated:NO]; 和 [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 Termating app due to uncaught exception 'NSInternalInconsistencyException ', 原因:'试图弹出到一个不存在的 View Controller 。'

以下是我如何跳转到 UIViewController2

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];
            }
        }

当我打印导航数组时，它在堆栈中显示 UIViewController2。我从编辑器中添加了 UINavigationController->embed in->Navigation Controller

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

在这里你实例化了一个新的 VC2 View Controller 实例，这不是你在导航 View Controller 堆栈上的实例!

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

所以你必须在

中找到正确的实例

[[self.navigationController] viewControllers]

解决方案 1:(如 iDev 所说，跳转到堆栈上的第二个 View Controller ，如果你知道它是第二个，请使用它)

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

方案二:(一般返回栈的第2层)

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