Xcode-当应用程序处于活动状态时(从后台返回)显示ViewController [英] Xcode - Show a ViewController when the app becomes active (coming back from the background)

问题描述

当应用程序从后台出现时，我想显示一个特定的ViewController.

I want to show a specific ViewController when the app comes foregrounded from the background.

我正在使用此方法来调用ViewController.

I am using this method to call a ViewController.

- (void)applicationWillEnterForeground:(UIApplication *)application
{
  [self presentMyViewController];
}

但是从后台返回时会有延迟.换句话说，您可以看到上一个视图，然后看到ViewController.我根本不想显示以前的视图.

But there is a delay when it comes back from the background. Or in other words, you can see the previous view, then you see the ViewController. I don't want to show the previous view at all.

如何实现呢?

推荐答案

在应用程序后台运行之前，在您的应用程序委托的applicationDidEnterBackground:方法中隐藏旧视图.实际上，这是Apple出于隐私原因特别推荐的一种机制

Hide the old view before the app is backgrounded, in your app delegate's applicationDidEnterBackground: method. This is in fact a mechanism that Apple specifically recommends for privacy reasons here:

在移至背景之前，从视图中删除敏感信息.当应用程序过渡到后台时，系统会为应用程序的主窗口拍摄快照，然后在将应用程序过渡回前台时短暂显示该快照.从applicationDidEnterBackground:方法返回之前，您应该隐藏或遮盖可能会在快照中捕获的密码和其他敏感个人信息.

Remove sensitive information from views before moving to the background. When an app transitions to the background, the system takes a snapshot of the app’s main window, which it then presents briefly when transitioning your app back to the foreground. Before returning from your applicationDidEnterBackground: method, you should hide or obscure passwords and other sensitive personal information that might be captured as part of the snapshot.

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