向NSString添加观察者 [英] Adding an observer to an NSString
本文介绍了向NSString添加观察者的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
在我的应用程序委托中,我有一个NSString,可以通过类进行修改.我要做的是让另一个类观察此NSString并在更改此NSString时做出反应.
In my application delegate I have an NSString which can be modified by a class. What I want to do is to have another class observe this NSString and to react whenever this NSString is changed.
有人知道我该怎么做吗?
Does anybody know how I can do this?
推荐答案
在其他课程"上,您必须执行以下操作:
On the "other class" you must do something like:
[MyAppDelegate addObserver:self forKeyPath:@"VARIABLE_NAME" options:NSKeyValueObservingOptionNew context:nil];
并实施
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context;
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