先引入名稱空間 UnityEngine.EventSystems,然後引入介面IDragHandler,IBeginDragHandler

Vector3 worldPos;

    Vector3 offset;
    public void OnBeginDrag(PointerEventData eventData)
    {
         
        if (RectTransformUtility.ScreenPointToWorldPointInRectangle(transform.GetComponent<RectTransform>(), Input.mousePosition
            , eventData.enterEventCamera, out worldPos))
        {
            offset = transform.position - worldPos;
            
        }
    }


    public void OnDrag(PointerEventData eventData)
    {
        transform.position = offset + Input.mousePosition;

    }

其中EventSystems還有如下功能

• IPointerEnterHandler - OnPointerEnter - Called when a pointer enters the object
• IPointerExitHandler - OnPointerExit - Called when a pointer exits the object
• IPointerDownHandler - OnPointerDown - Called when a pointer is pressed on the object
• IPointerUpHandler - OnPointerUp - Called when a pointer is released (called on the original the pressed object)
• IPointerClickHandler - OnPointerClick - Called when a pointer is pressed and released on the same object
• IInitializePotentialDragHandler - OnInitializePotentialDrag - Called when a drag target is found, can be used to initialise values
• IBeginDragHandler - OnBeginDrag - Called on the drag object when dragging is about to begin
• IDragHandler - OnDrag - Called on the drag object when a drag is happening
• IEndDragHandler - OnEndDrag - Called on the drag object when a drag finishes
• IDropHandler - OnDrop - Called on the object where a drag finishes
• IScrollHandler - OnScroll - Called when a mouse wheel scrolls
• IUpdateSelectedHandler - OnUpdateSelected - Called on the selected object each tick
• ISelectHandler - OnSelect - Called when the object becomes the selected object
• IDeselectHandler - OnDeselect - Called on the selected object becomes deselected
• IMoveHandler - OnMove - Called when a move event occurs (left, right, up, down, ect)
• ISubmitHandler - OnSubmit - Called when the submit button is pressed
• ICancelHandler - OnCancel - Called when the cancel button is pressed