KVO

讲述了NSObject派生对象如何使用KVO。注意：成员变量名对应就是Key。

@interface AppDelegate()

@property (strong, nonatomic) NSString *stockName;

@property (assign, nonatomic) float price;

@end

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

//    [self setValue:@"searph" forKey:@"stockName"];

//    [self setValue:@"10.0" forKey:@"price"];

[self addObserver:self forKeyPath

:@"price" options:NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld context:NULL];

self.stockName = @"searph";

self.price = 10.0;

NSLog(@"%@",[self valueForKey:@"price"]);

//    [self setValue:@"20.0" forKey:@"price"];

self.price = 20.0;

return YES;

}

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

{

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

{

NSLog(@"%@",[self valueForKey:@"price"]);

}

}

http://blog.csdn.net/yuquan0821/article/details/6646400/