ios 监听

创建一个监听

 /// 监听类(需要在监听类实现监听方法)   监听的对象  监听配置
[self addObserver:self forKeyPath:@"isBeginScroll" options:NSKeyValueObservingOptionNew context:nil];

监听方法

///监听方法
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context{
    
    if ([object isEqual:self]) {
        
        [self OwnObserveValueForKeyPath:keyPath ofObject:object change:change context:context];
        
    }
    
}

-(void)OwnObserveValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context{
    
   	if ([@"isBeginScroll"isEqualToString:keyPath]) {
       
       ///属性发生变化执行
       
  	}
    
}