Unity 鼠标拖动UI

第一种：

using UnityEngine;
using UnityEngine.EventSystems;

public class test : MonoBehaviour, IDragHandler
{

    private RectTransform rt;
    
    // Start is called before the first frame update
    void Start()
    {
        rt = GetComponent();
    }

    public void OnDrag(PointerEventData eventData)
    {

        Vector3 pos;
        
        if (RectTransformUtility.ScreenPointToWorldPointInRectangle
        (rt, eventData.position, eventData.pressEventCamera,out pos))
        {
            rt.position = pos;
        }

    }
」

当鼠标位置需要在ui的左上角时

    private Vector3 v3;
    
	void Start()
    {
        v3 = new Vector3(rt.rect.width / 2, -rt.rect.height / 2);
    }
	//在ui重新赋值的时候加上v3即可

第二种：
点在哪ui跟随到哪

using UnityEngine;
using UnityEngine.EventSystems;

public class DragUI : MonoBehaviour, IDragHandler, IPointerDownHandler {

    private Vector2 offsetPos;  

    public void OnDrag(PointerEventData eventData)
    {
        transform.position = eventData.position - offsetPos;
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        offsetPos = eventData.position - (Vector2)transform.position;
    }
}