KVC和KVO

KVC:
KVO:- (void)addObserver:(NSObject *)observer forKeyPath:(NSString *)keyPath options:(NSKeyValueObservingOptions)options context:(void *)context;
相當於觀察者機制,當你觀察的對象的值發生變化時會調用
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context;在這裏你可以對你的響應的對象做出響應的變化
需要在你的delloc中- (void)removeObserver:(NSObject *)observer forKeyPath:(NSString *)keyPath;