在应用程序退出时关闭模式视图控制器 [英] Dismiss modal view controller on application exit

问题描述

当用户按下按钮时，我有一个视图控制器(视图A)呈现一个模式视图(B)，视图B本身具有一个按钮来呈现视图C.我的问题是，如果用户在显示了视图B或C，下次启动该应用程序时将出现相同的视图.有没有办法在退出时关闭视图B和C或在应用程序启动时显示视图A? 谢谢您的帮助

I have a view controller (view A) presenting a modal view (B) when the user pushed a button and the view B has itself a button to present view C. My problem is that if the user exits the application when the view B or C is shown, the same view will appear next time the application is launched. Is there a way to dismiss the views B and C on exit or to show view A when the application starts? Thanks for your help

推荐答案

我假设您的意思是当应用程序进入后台时.

I assume by close you mean when the application enters the background.

在您的应用程序委托中，您可以通过applicationDidEnterBackground:方法关闭您的控制器.

In your app delegate you can via the applicationDidEnterBackground: method dismiss your controller.

最好的方法可能是在视图控制器类中添加一个观察者:

Best way would probably be to add an observer in your view controller class:

- (void) viewDidLoad {
    [super viewDidLoad];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(appClosing) name:@"appClosing" object:nil];
}

- (void) dealloc
{
    [[NSNotificationCenter defaultCenter] removeObserver:self name:@"appClosing" object:nil];
    [super dealloc];
}

- (void) appClosing
{
    [self dismissModalViewControllerAnimated:YES];
}

并将通知发布到您的应用程序委托中:

And post the notification in your app delegate:

- (void)applicationDidEnterBackground:(UIApplication *)application
{
     [[NSNotificationCenter defaultCenter] postNotificationName:@"appClosing" object:nil];
}

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