UIButton特殊用法

1.去掉高亮状态(selected状态和normal状态切换时候出现)

  button.adjustsImageWhenHighlighted = NO;

2.禁止触摸事件的2种方式

//会改变按钮的状态，颜色会变灰

button.enabled = NO;

//保持按钮原来的状态，颜色不会变

button.userInteractionEnabled = NO;

3.KVO来监控button的大小

//注册KVO方法

[btn addObserver:self   forKeyPath:@"bounds" options:NSKeyValueObservingOptionNew |NSKeyValueObservingOptionInitial context:nil];

//KVO回调

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

          if (object == btn && [keyPath isEqualToString:@"bounds"]){

                  [btn setTitle:NSStringFromCGSize(btn.bounds.size) forState:UIControlStateNormal];

                }

}