调用applicationDidBecomeActive时如何告诉活动视图控制器？ [英] How to tell the active view controller when applicationDidBecomeActive is called?

问题描述

我觉得我在这里错过了一个技巧...

I feel I am missing a trick here...

我只想在调用applicationDidBecomeActive时调用当前活动视图控制器上的viewDidLoad或viewDidAppear，所以我当应用程序从后台再次启动时，可以重置某些动画或其他内容。我的一些观点并不关心，但其他人真的需要知道。

I just want to call viewDidLoad or viewDidAppear on the current active view controller when applicationDidBecomeActive gets called, so I can reset some animations or whatever, when the app is started up again from the background. Some of my views don't care, but others really need to know.

我使用的是故事板，而我的app委托文件具有标准功能 - 但所有的都有EMPTY机构。例如，didFinishLaunchingWithOptions只返回YES而不执行任何操作。故事板自动完成我猜的所有事情。

I am using Storyboards and my app delegate file has the standard functions - but all with EMPTY bodies. For example, didFinishLaunchingWithOptions just returns YES and does nothing else. Storyboard automagically does everything I guess.

那么如何从我相当空白，无信息的应用代表那里与当前视图控制器交谈？

So how can I talk to the current view controller from my rather blank, information free, app delegate?

推荐答案

我建议使用通知。

在你的应用委托中，applicationdidBecomeActive方法放在这段代码中：

In your app delegate's applicationdidBecomeActive method put in this code:

[[NSNotificationCenter defaultCenter] postNotificationName:@"appDidBecomeActive" object:nil];

在当前活动视图控制器的init方法中订阅通知。

In your current active view controller's init method subscribe to the notification.

[[NSNotificationCenter defaultCenter] addObserver:self 
                                         selector:@selector(updateStuff)        
                                             name:@"appDidBecomeActive" 
                                           object:nil];

在你的控制器中实现updateStuff方法，你应该能够做任何你想做的事情。应用程序变为活动状态。

Implement the "updateStuff" method in your controller and you should be able to do whatever you want when the app becomes active.

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