Question

我遇到了popToRootViewController和NavigationControllerDelegate组合的奇怪崩溃。在Storyboard中创建了3个tableViewControllers。 RootViewController - secondViewController - ThirdViewController 然后我想在ThirdViewController上使用popToRootViewController。弹出工作正常，但立即崩溃或在RootView上点击其他东西时。我在popToRootViewController之后发现NavigationController的childViewControllers是0，但是当逐个弹出后退按钮时，它不会崩溃。

当我禁用NavigationController的委托时，它解决了崩溃，而childViewControllers不会为0。但我需要NavigationController委托来禁用我用来验证用户输入的textfield的委托。（即如果用户将强制文本字段留空，则navigationController的委托将在推送/弹出视图之前禁用文本字段委托，以避免由文本字段委托触发alertView，这可以正常工作）。

这是显示childViewControllers count = 0的NSLog输出。我正在计算pop / push视图时childViewControllers的数量。

App启动时（在ViewdDidAppeared中显示NSLog）

2013-06-11 13:05:29.287 MyApp[1389:c07] Childviewcontrollers in Root's viewDidAppear = 1
2013-06-11 13:05:29.289 MyApp[1389:c07] Childviewcontrollers in Root's viewDidAppear = (
   "<RootViewController: 0x83239d0>"
)

将root推送到第二个

2013-06-11 13:05:41.955 MyApp[1389:c07] delegate enabled
2013-06-11 13:05:41.956 MyApp[1389:c07] childviewcontrollers count in SecondViewController's NavControlDelegate 2
2013-06-11 13:05:41.956 MyApp[1389:c07] childviewcontrollers in SecondViewController's NavControlDelegate (
    "<RootViewController: 0x83239d0>",
    "<SecondViewController: 0xfb0ee60>"
)
2013-06-11 13:05:42.322 MyApp[1389:c07] childviewcontrollers count in Second's ViewDidAppear 2
2013-06-11 13:05:42.322 MyApp[1389:c07] childviewcontrollers in Second's ViewDidAppear (
    "<RootViewController: 0x83239d0>",
    "<SecondViewController: 0xfb0ee60>"
)

第二到第三

2013-06-11 13:05:51.945 MyApp[1389:c07] childviewcontrollers count in SecondViewController's NavControlDelegate 3
2013-06-11 13:05:51.945 MyApp[1389:c07] childviewcontrollers in SecondViewController's NavControlDelegate (
    "<RootViewController: 0x83239d0>",
    "<SecondViewController: 0xfb0ee60>",
    "<ThirdViewController: 0x832f050>"
)
2013-06-11 13:05:52.302 MyApp[1389:c07] childviewcontrollers count in Third's ViewDidAppear 3
2013-06-11 13:05:52.303 MyApp[1389:c07] childviewcontrollers in Third's ViewDidAppear (
    "<RootViewController: 0x83239d0>",
    "<SecondViewController: 0xfb0ee60>",
    "<ThirdViewController: 0x832f050>"

第三个popToRootViewController。

2013-06-11 13:06:02.284 MyApp[1389:c07] Delegate disabled
2013-06-11 13:06:02.284 MyApp[1389:c07] childviewcontrollers in SecondViewController's NavControlDelegate 0
2013-06-11 13:06:02.284 MyApp[1389:c07] childviewcontrollers in SecondViewController's NavControlDelegate (null)

但是RootViewController是新创建的吗？但无论如何它都会崩溃。

2013-06-11 13:06:02.642 MyApp[1389:c07] Childviewcontrollers in Root's viewDidAppear = 1
2013-06-11 13:06:02.642 MyApp[1389:c07] Childviewcontrollers in Root's viewDidAppear = (
    "<RootViewController: 0x83239d0>"
)

作为参考，下面是我禁用navigationController的委托时的日志。如果有任何关于解决这个问题的建议，我们将非常感激。

2013-06-11 13:07:06.349 MyApp[1412:c07] Childviewcontrollers count in Root's viewDidAppear = 1
2013-06-11 13:07:06.350 MyApp[1412:c07] Childviewcontrollers in Root's viewDidAppear = (
    "<RootViewController: 0x8184680>"
)
2013-06-11 13:07:08.265 MyApp[1412:c07] delegate enabled
2013-06-11 13:07:08.632 MyApp[1412:c07] childviewcontrollers count in Second's ViewDidAppear 2
2013-06-11 13:07:08.632 MyApp[1412:c07] childviewcontrollers in Second's ViewDidAppear (
    "<RootViewController: 0x8184680>",
    "<SecondViewController: 0xa969ca0>"
)
2013-06-11 13:07:15.442 MyApp[1412:c07] childviewcontrollers count in Third's ViewDidAppear 3
2013-06-11 13:07:15.443 MyApp[1412:c07] childviewcontrollers in Third's ViewDidAppear (
    "<RootViewController: 0x8184680>",
    "<SecondViewController: 0xa969ca0>",
    "<ThirdViewController: 0x74a6a30>"
)
2013-06-11 13:07:18.994 MyApp[1412:c07] Childviewcontrollers count in Root's viewDidAppear = 1
2013-06-11 13:07:18.994 MyApp[1412:c07] Childviewcontrollers in Root's viewDidAppear = (
    "<RootViewController: 0x8184680>"
)

此致

ChildViewController = 0然后在popToRootViewController之后崩溃

0 个答案: