使用presentViewController时不调用viewDidDisappear [英] viewDidDisappear not called when use presentViewController

问题描述

我有一个 UIViewController 有这个方法:

I have an UIViewController having this method:

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    NSLog(@"DISAPPEAR");
    lastKnownOrientation = [self interfaceOrientation];
}


-(void)openSendVC{
    SendMsgViewController *vc = [[SendMsgViewController alloc]initWithNibName:@"SendMsgViewController" bundle:nil];
    [self.navigationController pushViewController:vc animated:NO];  
}

在第二个视图控制器 (SendMsgViewController) viewDidLoad 我有以下内容:

In the second view controller (SendMsgViewController) viewDidLoad I have the following:

[self presentViewController:picker animated:YES completion:NULL];

picker 是一个 UIImageViewPicker.

where picker is an UIImageViewPicker.

问题是，当我调用方法 openSendVC 时，会打开一个新控制器，但没有调用 viewWillDisappear(第一个 viewController 的).

The problem is, when I call the method openSendVC a new controller is opened, but viewWillDisappear (of the first viewController) is not called.

推荐答案

这是正确的行为.以下是关于 viewWillDisappear: 的摘录，来自 UIViewController API 文档:

That is the correct behavior. Here's an excerpt about viewWillDisappear: from the UIViewController API docs:

调用此方法是为了响应从视图层次结构中删除的视图.在实际移除视图和配置任何动画之前调用此方法.

This method is called in response to a view being removed from a view hierarchy. This method is called before the view is actually removed and before any animations are configured.

呈现一个新的视图控制器以隐藏另一个视图控制器不算作视图消失——实际上只有从视图层次结构中删除才算作(例如，使用类似 popViewControllerAnimated: 的东西).

Presenting a new view controller so that it hides the other view controller doesn't count as the view disappearing—only actually being removed from a view hierarchy does (e.g., with something like popViewControllerAnimated:).

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