从另一个视图控制器中删除通知观察者 [英] Remove notification observer from another view controller

问题描述

我正在开发 Iphone 应用程序，其中正在为 UIApplicationWillEnterForegroundNotification 注册一个通知观察者.现在我想从另一个视图控制器中删除那个.我的代码看起来像

Hi I am developing Iphone application in which am registering one notification observer for UIApplicationWillEnterForegroundNotification. Now I want to remove that one from another view controller. My code looks like

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

我正在创建一种删除观察者的方法:

And I am creating one method for removing observer:

-(void) removeObserver
{
  [[NSNotificationCenter defaultCenter] removeObserver:self]; 
} 

我正在从其他视图控制器调用此方法，但它不起作用.我想我必须存储观察者.但我不知道如何做到这一点.需要帮忙.谢谢.

and I am calling this method from other view controller but its not working. I think I have to store observer. But I don't know how to do this. Need help. Thank you.

推荐答案

第二个视图控制器需要引用第一个视图控制器的实例.让我们假设它保存在一个属性中:

The second view controller needs a reference to the instance of the first view controller. Let's assume it is hold in a property:

@property (nonatomic, strong) FirstViewControler *firstViewController;

然后，您作为观察者移除第一个视图控制器的代码如下所示:

Then your code to remove the fist view controller as an observer would look like this:

- (void)removeObserver
{
    [[NSNotificationCenter defaultCenter] removeObserver:self.firstViewController]; 
}

缺少的部分是:您必须在某处设置属性.在何处执行此操作取决于您的代码.

The missing part is: You have to set the property somewhere. Where to do that depends on your code.

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