[IOS學習筆記]KVO

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//屬性@property(nonatomic) BOOL isFinished;
//註冊監聽 [self addObserver:self forKeyPath:@"isFinished" options:0 context:NULL];
//響應變更事件- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context{    if ([keyPath isEqualToString:@"isFinished"]) {        NSLog(@"changeeddd");    } else {        [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];    }}
//變更屬性數值[button addTarget:self action:@selector(changeFinished:) forControlEvents:UIControlEventTouchUpInside];-(void)changeFinished:(id)sender {//自動通知    [self setValue:[NSNumber numberWithBool:YES] forKey:@"isFinished"];}

註冊監聽器參數 options

NSKeyValueObservingOptionNew 表示屬性未改變?之前的值；

NSKeyValueObservingOptionOld 表示屬性改變後的值；?

 

移除觀察者：

[subject removeObserver:observer forKeyPath:@"name"]; 

 

KVO相當於JAVA:

account.setListener(new MyListener(){

    inspector.method();

});

 

但是不需要和JAVA一樣聲明一個MyListener介面，也不需要在account類中建立一個setListeber(MyListener listener);的方法，所以更靈活,但是變更屬性時不能簡單賦值！

 

[IOS學習筆記]KVO