iOS：警告“尝试呈现其视图不在窗口层次结构中的ViewController” [英] iOS: Warning "attempt to present ViewController whose view is not in the window hierarchy"

问题描述

当我尝试在导航控制器上显示ActivityController时，我收到以下警告，

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

Attempt to present <UIActivityViewController: 0x15be1d60> on <UINavigationController: 0x14608e80> whose view is not in the window hierarchy!

我试图通过以下代码呈现视图控制器，

I have tried to present view controller by following code,

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");

    }];

这里出了什么问题？

推荐答案

您正在尝试从 rootViewController 中呈现视图控制器。在你的情况下，我认为 rootViewController 不是当前的ViewController。您在其上面呈现或推送了新的 UIViewController 。您应该从最顶层的视图控制器本身提供一个视图控制器。

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];

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