iOS:警告“试图呈现视图不在窗口层次结构中的视图控制器”

I am getting following warning when I try to present a ActivityController on navigation controller,

当我试图在导航控制器上显示一个ActivityController时，

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,

我尝试用下面的代码来呈现视图控制器，

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 ?

这里出什么问题了?

4 个解决方案

#1

You are trying to present a view controller from the rootViewController. In your case I think the rootViewController is not the current ViewController. Either you presented or pushed a new UIViewController on top of it. You should present a view controller from the top most view controller itself.

您正在尝试从rootViewController中显示一个视图控制器。在你的例子中，我认为rootViewController不是当前的ViewController。你可以在上面展示或推送一个新的UIViewController。您应该从最上面的视图控制器本身显示一个视图控制器。

You need to change:

您需要更改:

UIViewController *vc = self.view.window.rootViewController;
[vc presentViewController: activityController animated: YES completion:nil];

to:

[self presentViewController: activityController animated: YES completion:nil];

#2

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类没有被加载到窗口。这相当于大楼，二楼还没盖，直接去盖三层，这绝对不是。只在加载ViewController的视图之后;

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.

这是为我工作。

#3

Replace line:

取代线:

UIViewController *vc = self.view.window.rootViewController;
[vc presentViewController: activityController animated: YES completion:nil];
//to
[self presentViewController:activityController animated: YES completion:nil];

或

[self.navigationController pushViewController:activityController animated:YES];

#4

-6

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

在斯威夫特2.0

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.

我用这种方法解出来了。

#1