使用storyboard从appdelegate访问视图控制器 [英] Access a view controller from appdelegate using storyboard

问题描述

我遵循了这个Ray Wendelich教程
使用故事板的RayWenderlichTutorial Tabbarcontroller

I have followed this Ray Wendelich Tutorial RayWenderlichTutorial Tabbarcontroller using storyboards

只需查看故事板图像即可。
Ray使用以下代码访问'playersViewcontroller'

Just see the storyboard image. Ray is accesing 'playersViewcontroller using the below code'

 UITabBarController *tabBarController = (UITabBarController *)self.window.rootViewController;
UINavigationController *navigationController = [tabBarController viewControllers][0];
PlayersViewController *playersViewController = [navigationController viewControllers][0];

当我试图访问playerDetailsViewController时，使用以下代码我会崩溃。给出消息

When I'm trying to access playerDetailsViewController, using the following code i get a crash. Giving the message

评级[2630：60b] *由于未捕获的异常'NSRangeException'终止应用程序，原因：'* - [__ NSArrayI objectAtIndex：]：索引1超出边界[0 .. 0]'
***第一次调用堆栈：
（0x30b49e83 0x3aea66c7 0x30a7fff9 0x3ddd1 0x3333eaad 0x3333e4f3 0x33338b41 0x332d3a07 0x332d2cfd 0x33338321 0x357b876d 0x357b8357 0x30b14777 0x30b14713 0x30b12edf 0x30a7d471 0x30a7d253 0x333375c3 0x33332845 0x3e0fd 0x3b39fab7）
libc ++ abi.dylib：以NSException类型的未捕获异常终止

Ratings[2630:60b] * Terminating app due to uncaught exception 'NSRangeException', reason: '* -[__NSArrayI objectAtIndex:]: index 1 beyond bounds [0 .. 0]' *** First throw call stack: (0x30b49e83 0x3aea66c7 0x30a7fff9 0x3ddd1 0x3333eaad 0x3333e4f3 0x33338b41 0x332d3a07 0x332d2cfd 0x33338321 0x357b876d 0x357b8357 0x30b14777 0x30b14713 0x30b12edf 0x30a7d471 0x30a7d253 0x333375c3 0x33332845 0x3e0fd 0x3b39fab7) libc++abi.dylib: terminating with uncaught exception of type NSException

代码

UITabBarController *tabBarController =
(UITabBarController *)self.window.rootViewController;
UINavigationController *navigationController =
[[tabBarController viewControllers] objectAtIndex:0];
PlayersViewController *playersViewController =
[[navigationController viewControllers] objectAtIndex:0];

UINavigationController *nav=[[navigationController viewControllers]objectAtIndex:1];
PlayerDetailsViewController *playerdetailsviewcontroller=[[nav viewControllers]objectAtIndex:0];

我也试过以下代码，

UITabBarController *tabBarController =
(UITabBarController *)self.window.rootViewController;
UINavigationController *navigationController =
[[tabBarController viewControllers] objectAtIndex:0];
PlayersViewController *playersViewController =
[[navigationController viewControllers] objectAtIndex:0];
PlayerDetailsViewController *playerdetailsviewcontroller=[[navigationController viewControllers]objectAtIndex:1];

我的邮件崩溃

'NSRangeException'，原因：'*** - [__ NSArrayI objectAtIndex：]：索引1超出界限[0 .. 0]'

'NSRangeException', reason: '*** -[__NSArrayI objectAtIndex:]: index 1 beyond bounds [0 .. 0]'

故事板图片

The storyboard image

基本上我想从appdelegate访问PlayerdetailsViewcontroller。
我想我错过了什么，有什么想法吗？

Basically i want to access the PlayerdetailsViewcontroller from appdelegate. I think I'm missing something, any thoughts?

推荐答案

你的应用程序在这里崩溃了（ objectAtIndex：1 ）：

Your app crashes here (objectAtIndex:1):

UINavigationController *nav = [[navigationController viewControllers] objectAtIndex:1];
PlayerDetailsViewController *playerdetailsviewcontroller = [[nav viewControllers]objectAtIndex:0];

这是因为 naviationController 只有1个子视图（ PlayersViewController ）。如果不通过Segue在 PlayersViewController 中实例化 PlayerDetailsViewController ，你就无法进入故事板。

This happens because naviationController has only 1 subview (PlayersViewController). You can't go further down the storyboard without instantiating the PlayerDetailsViewController within PlayersViewController via a Segue.

编辑
您只能访问最初可见的 ViewControllers （通过 UITabBarController ）。

我也不明白你为什么要添加另一个 UINavigationController 到 PlayersViewController 。如果您使用Segue navigationController 将 PlayersViewController 连接到 PlayerDetailViewController 将被重用（这将是正确的方法）。

I also don't get why you're adding another UINavigationController to the PlayersViewController. If you connect PlayersViewController to PlayerDetailViewController with a Segue the navigationController will be reused (this would be the correct way to do so).

这篇关于使用storyboard从appdelegate访问视图控制器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！