在unity中，有这么一些接口 IPointerClickHandler,IPointerEnterHandler,IPointerExitHandler,IPointerMoveHandler,IPointerUpHandler,IPointerDownHandler,IInitializePotentialDragHandler,IBeginDragHandler,IDragHandler,IEndDragHandler,IDropHandler,IScrollHandler,IUpdateSelectedHandler,ISelectHandler,IDeselectHandler,...