KVO的使用(键值监听)

Key-Value Observing  键值监听。

  

   

    

     

    
    

     

      stockForKVO = [[StockData alloc] init];  
     
    
   

    

     

    
    

     

          [stockForKVO setValue:@"searph" forKey:@"stockName"];  
     
    
   

    

     

    
    

     

          [stockForKVO setValue:@"10.0" forKey:@"price"];      
     
    
   

    

     

    
    

     

          [stockForKVO addObserver:self forKeyPath:@"price" options:NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld context:NULL]; 
     
    
  
 

  

   

    

     

    
    

     

      -(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
     
    
   

    

     

    
    

     

      {
     
    
   

    

     

    
    

     
    if([keyPath isEqualToString:@"price"])
     
    
   

    

     

    
    

     

          {
     
    
   

    

     

    
    

     

              myLabel.text = [stockForKVO valueForKey:@"price"];
     
    
   

    

     

    
    

     

          }
     
    
   

    

     

    
    

     

      }
     
    
  
 

  

   

    

     

    
    

     

      - (void)dealloc
     
    
   

    

     

    
    

     

      {
     
    
   

    

     

    
    

     

          [super dealloc];
     
    
   

    

     

    
    

     

          [stockForKVO removeObserver:self forKeyPath:@"price"];
     
    
   

    

     

    
    

     

          [stockForKVO release];
     
    
   

    

     

    
    

     

      }
     
    
  
 

文章来源: zzzili.blog.csdn.net，作者：清雨小竹，版权归原作者所有，如需转载，请联系作者。

原文链接：zzzili.blog.csdn.net/article/details/38895197