xcode Objective-C：其视图不在窗口层次结构中
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Objective-C: whose view is not in the window hierarchy
提问by user2536879
I have this code that works so that once i press a button the view changes in my storyboard:
我有这段代码可以工作，所以一旦我按下按钮，我的故事板中的视图就会发生变化：
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
ViewController *viewController = (ViewController *)[storyboard instantiateViewControllerWithIdentifier:@"view1"];
[self presentViewController:viewController animated:YES completion:nil];
This code work but when i use it again to change back to my original view using:
此代码有效，但是当我再次使用它以使用以下方法更改回原始视图时：
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
ViewController *viewController = (ViewController *)[storyboard instantiateViewControllerWithIdentifier:@"view2"];
[self presentViewController:viewController animated:YES completion:nil];
It does not work and i receive this error:
它不起作用，我收到此错误：
Warning: Attempt to present <UIViewController: 0x863ad30> on <UITabBarController: 0x86309b0> whose view is not in the window hierarchy!
The identifies are set and i am not the functions in my viewdidloadso i do not know how to fix this.
标识已设置，我不是我的功能，viewdidload所以我不知道如何解决这个问题。
Can anybody help?
有人可以帮忙吗？
回答by aToz
Try this,
尝试这个，
First Method
第一种方法
-(IBAction)signin:(id)sender
{
UIStoryboard *sb = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
UIViewController *vc = [sb instantiateViewControllerWithIdentifier:@"viewController"];
[[[[UIApplication sharedApplication] delegate] window] setRootViewController:vc];
}
Second method (to return back to the previous view)
第二种方法（返回上一个视图）
- (IBAction)signout:(id)sender
{
UIStoryboard *sb = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
UIViewController *vc = [sb instantiateViewControllerWithIdentifier:@"parentViewController"];
[[[[UIApplication sharedApplication] delegate] window] setRootViewController:vc];
}
回答by Tarek Hallak
This might happen if you call the method before calling makeKeyAndVisible, so move the calling after that.
如果您在调用之前调用方法，则可能会发生这种情况makeKeyAndVisible，因此请在调用之后移动调用。
If not try the hack below:
如果没有尝试下面的黑客：
[[[[[UIApplication sharedApplication] delegate] window] rootViewController] presentViewController:viewController animated:YES completion:nil];
回答by Ramy Al Zuhouri
The error message says all: you have to add the view controller's view to the window before presenting the view controller:
错误消息说明了一切：在呈现视图控制器之前，您必须将视图控制器的视图添加到窗口中：
UIWindow* keyWindow= [[UIApplication sharedApplication] keyWindow];
[keyWindow addSubview: viewController.view];
[self presentViewController:viewController animated:YES completion:nil];
