IPointerEnterHandler-OnPointerEnter,鼠标进入时调用

IPointerExitHandler-OnPointerExit,鼠标退出时调用

IPointerDownHandler-OnPointerDown,鼠标按下时调用

IPointerUpHandler-OnPointerUp,鼠标抬起时调用

IPointerClickHandler-OnPointerClick,鼠标按下并抬起时调用