iOS - NavigationController 认为同一个控制器被推了两次
我对下面的代码有点困惑。如果我注释掉第二条语句，它会成功显示视图：
MyAppDelegate *delegate = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];
delegate.navController.viewControllers = [NSArray arrayWithObject:aViewController];
[delegate.navController pushViewController:aViewController animated:YES];
[aViewController release];
否则，它会在以下情况下崩溃：
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Pushing the same view controller instance more than once is not supported
我在应用程序委托中添加了一个不同的视图控制器，但不是这个。是什么让它认为这是同一个？
I'm a bit confused about the following code. If I comment out the second statement, it successfully shows the view:
MyAppDelegate *delegate = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];
delegate.navController.viewControllers = [NSArray arrayWithObject:aViewController];
[delegate.navController pushViewController:aViewController animated:YES];
[aViewController release];
Otherwise, it crashes on the following:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Pushing the same view controller instance more than once is not supported
I add a different view controller in the app delegate, but not this one. What could be making it think it's the same one?
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第一行将 aViewController 设置为 navController 的唯一控制器。第二行再次将 aViewController 推送到 navController ，所以是的，难怪你会得到它两次。根据您想要做什么，放弃这两行之一。
如果你想将 aViewController 设置为 navController 上的唯一控制器，请保留第一行。
如果你想将 aViewController 作为 navController 上的新控制器推送，请保留第二行。
First line set's aViewController as navController's only controller. Second line pushes aViewController to navController again so yeah, no wonder you get it twice. Depending on what you want to do, ditch one of those two lines.
If you want to set aViewController as only controller on navController, keep first line.
If you want to push aViewController as a new controller on navController, keep second line.