尝试呈现* on *，其视图不在窗口层次结构中 [英] Attempt to present * on * whose view is not in the window hierarchy

问题描述

我想在我的应用程序委托（我创建了一个名为showLoginView的函数）模态视图控制器。但是每当我尝试调用它，我在XCode中收到一个警告：

I'm trying to make a modal view controller in my app delegate (I created a function called showLoginView). But whenever I try to call it I get a warning in XCode:

Warning: Attempt to present <PSLoginViewController: 0x1fda2b40> on <PSViewController: 0x1fda0720> whose view is not in the window hierarchy!

以下是方法代码：

- (void)showLoginView
{
    PSLoginViewController *loginViewController = [[UIStoryboard storyboardWithName:@"MainStoryboard" bundle:NULL] instantiateViewControllerWithIdentifier:@"PSLoginViewController"];
    [self.window.rootViewController presentViewController:loginViewController animated:NO completion:nil];
}

如何将视图添加到窗口层次结构？

How can I add the view to the window hierarchy? Or maybe I'm doing something very wrong?

推荐答案

您不能从appDelegate显示模态视图控制器。您需要从任何viewController当前显示全屏显示模式ViewController。换句话说，你需要把这个代码放到你的根视图控制器，或者任何一个你想显示模态vc从...

You can't display a modal view controller from the appDelegate. You need to display a modal ViewController from whichever viewController is currently displaying full-screen. In other words, you need to put that code into your root view controller, or whichever one you want to display the modal vc from...

想要使用方法presentModalViewController来呈现模态。您可以在模态vc上设置属性，例如：

Also, you'll want to use the method "presentModalViewController" to present the modal. You can set properties on the modal vc such as:

vC.modalPresentationStyle = UIModalPresentationFormSheet;
vC.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentModalViewController:vC animated:YES];

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