iOS NSNotificationCenter 检查应用程序是否从后台到前台 [英] iOS NSNotificationCenter to check whether the app came from background to foreground

问题描述

我有一种情况，每次从后台到前台时我都必须初始化一个对象，并且应该使用 NSNotificationCenter 而不是 appdelegate 因为我正在构建一个静态库所以不会有 appdelegate 所以请帮助我同样.

I have a situation in which i have to intialize an object everytime when it comes from background to foreground and that should be using the NSNotificationCenter not with appdelegate because iam building a static library so there wont be appdelegate with that so please help me in the same.

推荐答案

你试过UIApplicationWillEnterForegroundNotification吗?

该应用还会在调用 applicationWillEnterForeground: 之前不久发布 UIApplicationWillEnterForegroundNotification 通知，让感兴趣的对象有机会响应转换.

The app also posts a UIApplicationWillEnterForegroundNotification notification shortly before calling applicationWillEnterForeground: to give interested objects a chance to respond to the transition.

订阅通知:

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(yourUpdateMethodGoesHere:)
                                             name:UIApplicationWillEnterForegroundNotification
                                           object:nil];

实现一个需要调用的代码:

Implement a code, that need to be called:

- (void) yourUpdateMethodGoesHere:(NSNotification *) note {
// code
}

别忘了退订:

[[NSNotificationCenter defaultCenter] removeObserver:self];

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