https://developer.apple.com/library/ios/documentation/EventHandling/Conceptual/EventHandlingiPhoneOS/GestureRecognizer_basics/GestureRecognizer_basics.html 轻点相当于点击,是指快速触摸开始和结束(算作一个事件) 触摸可能是持久的...你可以按下去,然后移动手指到按钮上,然后抬起手指会触发touch up(在按钮内部)