iOS：警告“尝试呈现其视图不在窗口层次结构中的 ViewController”
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iOS: Warning "attempt to present ViewController whose view is not in the window hierarchy"
提问by iOSNoob
I am getting following warning when I try to present a ActivityController on navigation controller,
当我尝试在导航控制器上显示 ActivityController 时收到以下警告，
Attempt to present <UIActivityViewController: 0x15be1d60> on <UINavigationController: 0x14608e80> whose view is not in the window hierarchy!
I have tried to present view controller by following code,
我尝试通过以下代码呈现视图控制器，
UIActivityViewController * activityController = [[UIActivityViewController alloc] initWithActivityItems:activityItems applicationActivities:applicationActivities];
activityController.excludedActivityTypes = excludeActivities;
UIViewController *vc = self.view.window.rootViewController;
[vc presentViewController: activityController animated: YES completion:nil];
[activityController setCompletionHandler:^(NSString *activityType, BOOL completed) {
NSLog(@"completed");
}];
Whats going wrong here ?
这里出了什么问题？
采纳答案by Midhun MP
You are trying to present a view controller from the rootViewController. In your case I think the rootViewControlleris not the current ViewController. Either you presented or pushed a new UIViewControlleron top of it. You should present a view controller from the top most view controller itself.
您正在尝试从rootViewController. 在您的情况下，我认为这rootViewController不是当前的 ViewController。你要么UIViewController在它上面展示了一个新的，要么在它上面推了一个新的。您应该从最顶层的视图控制器本身呈现一个视图控制器。
You need to change:
你需要改变：
UIViewController *vc = self.view.window.rootViewController;
[vc presentViewController: activityController animated: YES completion:nil];
to:
到：
[self presentViewController: activityController animated: YES completion:nil];
回答by qingsong
Analysis： Because the present modal view ViewController class has not been loaded into the window. This is equivalent to the building, second floor haven't built, directly go to cover 3 floor, this is definitely not. Only after load ViewController's view ;
分析： 因为当前模态视图ViewController类还没有加载到窗口中。这相当于建了，二楼还没建，直接去盖3楼，这绝对不行。只有在加载 ViewController 的视图之后；
Python
Python
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
[self showAlertViewController];
}
- (void)showAlertViewController {
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Hello world" message:@"(* ￣3)(ε￣ *)d" preferredStyle:UIAlertControllerStyleAlert];
// Create the actions.
UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"hello" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
NSLog(@"The \"Okay/Cancel\" alert's cancel action occured.");
}];
UIAlertAction *otherAction = [UIAlertAction actionWithTitle:@"world" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
NSLog(@"The \"Okay/Cancel\" alert's other action occured.");
}];
// Add the actions.
[alertController addAction:cancelAction];
[alertController addAction:otherAction];
UIWindow *windows = [[UIApplication sharedApplication].delegate window];
UIViewController *vc = windows.rootViewController;
[vc presentViewController:alertController animated: YES completion:nil];
}
This's worked for me.
这对我有用。
回答by Bhadresh Kathiriya
Replace line:
替换线：
UIViewController *vc = self.view.window.rootViewController;
[vc presentViewController: activityController animated: YES completion:nil];
//to
[self presentViewController:activityController animated: YES completion:nil];
or
或者
[self.navigationController pushViewController:activityController animated:YES];
回答by Abdul Hameed
I faced the similar issue in iPhone 6+.
我在 iPhone 6+ 中遇到了类似的问题。
In Swift 2.0
在 Swift 2.0 中
let obj = self.storyboard?.instantiateViewControllerWithIdentifier("navChatController") as! UINavigationController
obj.modalPresentationStyle = .FormSheet
obj.modalTransitionStyle = .CoverVertical
Constants.APPDELEGATE.window?.rootViewController?.presentViewController(obj, animated: false, completion: nil)
I solved it by this way.
我是这样解决的。
