Unity 简单的拖拽UI实现(不触发Btn事件，有屏幕范围判定)

/**
 *Copyright(C) 2019 by #COMPANY#
 *All rights reserved.
 *FileName:     #SCRIPTFULLNAME#
 *Author:       #AUTHOR#
 *Version:      #VERSION#
 *UnityVersion：#UNITYVERSION#
 *Date:         #DATE#
 *Description:   
 *History:
*/
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
public class Drag : MonoBehaviour
{
    private void Start()
    {
        transform.GetComponent<Button>().onClick.AddListener(() =>
        {
            Debug.Log("点击了");
        });
    }
    // Update is called once per frame
    void Update()
    {
        if (Input.GetMouseButtonDown(0))
        {
            Vector2 mousePos2D = Input.mousePosition;
            RaycastHit2D hit = Physics2D.Raycast(mousePos2D, Vector2.zero);
            if (hit.transform != null)
            {
                var listener = EventTriggerListener.Get(hit.transform);
                Vector3 offset = Vector3.zero;
                Button btn = hit.transform.GetComponent<Button>();
                listener.onBeginDrag += (go) =>
                {
                    if (btn!=null)
                    {
                        btn.enabled = false;
                    }
                    offset = hit.transform.position - Input.mousePosition;
                };
                listener.onDrag += (go) =>
                {
                    hit.transform.position = Input.mousePosition + offset;
                    DragRangeLimit(hit.transform);
                };
                listener.onEndDrag += (go) =>
                {
                    if (btn != null)
                    {
                        btn.enabled = true;
                    }
                };
            }
        }
    }

    /// <summary>
    /// 限制移动距离在屏幕内
    /// </summary>
    /// <param name="tra"></param>
    public void DragRangeLimit(Transform tra)
    {
        var pos = tra.GetComponent<RectTransform>();
        float x = Mathf.Clamp(pos.position.x, pos.rect.width * 0.5f, Screen.width - (pos.rect.width * 0.5f));
        float y = Mathf.Clamp(pos.position.y, pos.rect.height * 0.5f, Screen.height - (pos.rect.height * 0.5f));
        pos.position = new Vector2(x, y);
    }
}

需要一个类似于NGUI的事件监听类


using UnityEngine;
using UnityEngine.EventSystems;
using System.Collections;
using System;

public class EventTriggerListener : EventTrigger
{
    public delegate void VoidDelegate(GameObject go);
    public VoidDelegate onClick;
    public VoidDelegate onDown;
    public VoidDelegate onEnter;
    public VoidDelegate onExit;
    public VoidDelegate onUp;
    public VoidDelegate onSelect;
    public VoidDelegate onUpdateSelect;
    public VoidDelegate onDrag;
    public VoidDelegate onBeginDrag;
    public VoidDelegate onEndDrag;

    public static EventTriggerListener Get(GameObject go)
    {
        EventTriggerListener listener = go.GetComponent<EventTriggerListener>();
        if (listener == null)
            listener = go.AddComponent<EventTriggerListener>();
        return listener;
    }

    public static EventTriggerListener Get(Transform go)
    {
        EventTriggerListener listener = go.GetComponent<EventTriggerListener>();
        if (listener == null)
            listener = go.gameObject.AddComponent<EventTriggerListener>();
        return listener;
    }

    public override void OnPointerClick(PointerEventData eventData)
    {
        if (onClick != null) onClick(gameObject);
    }
    public override void OnPointerDown(PointerEventData eventData)
    {
        if (onDown != null) onDown(gameObject);
    }
    public override void OnPointerEnter(PointerEventData eventData)
    {
        if (onEnter != null) onEnter(gameObject);
    }
    public override void OnPointerExit(PointerEventData eventData)
    {
        if (onExit != null) onExit(gameObject);
    }
    public override void OnPointerUp(PointerEventData eventData)
    {
        if (onUp != null) onUp(gameObject);
    }
    public override void OnSelect(BaseEventData eventData)
    {
        if (onSelect != null) onSelect(gameObject);
    }
    public override void OnUpdateSelected(BaseEventData eventData)
    {
        if (onUpdateSelect != null) onUpdateSelect(gameObject);
    }

    public override void OnDrag(PointerEventData eventData)
    {
        if (onDrag != null) onDrag(gameObject);
    }

    public override void OnBeginDrag(PointerEventData eventData)
    {
        if (onBeginDrag != null) onBeginDrag(gameObject);
    }

    public override void OnEndDrag(PointerEventData eventData)
    {
        if (onEndDrag != null) onEndDrag(gameObject);
    }
}

按下btn失活抬起激活这样就实现了移动图标不会激活Btn事件
需要注意的是要拖拽的物体要添加2D碰撞这个脚本只用挂一个.不用每个物体都挂根据2D射线碰撞拖动

这样的话有个问题就是你按下才注册按下事件所以第一次按下事件不会触发第二次才会每次点击到都要重新注册
所以更改一下在btn界面传入transform注册

/**
 *Copyright(C) 2019 by #COMPANY#
 *All rights reserved.
 *FileName:     #SCRIPTFULLNAME#
 *Author:       #AUTHOR#
 *Version:      #VERSION#
 *UnityVersion：#UNITYVERSION#
 *Date:         #DATE#
 *Description:   
 *History:
*/
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
public class Drag : MonoBehaviour
{
    bool canTouch=true;
    private void Start()
    {
        RegisterDrag(transform);
        transform.GetComponent<Button>().onClick.AddListener(() =>
        {
            Debug.Log("点击了");        
        });
    }
    // Update is called once per frame
    void Update()
    {
       
            
        
    }

    /// <summary>
    /// 限制移动距离在屏幕内
    /// </summary>
    /// <param name="tra"></param>
    public void DragRangeLimit(Transform tra)
    {
        var pos = tra.GetComponent<RectTransform>();
        float x = Mathf.Clamp(pos.position.x, pos.rect.width * 0.5f, Screen.width - (pos.rect.width * 0.5f));
        float y = Mathf.Clamp(pos.position.y, pos.rect.height * 0.5f, Screen.height - (pos.rect.height * 0.5f));
        pos.position = new Vector2(x, y);
    }

    public void RegisterDrag(Transform tra)
    {
        if (tra.transform != null)
        {
            var listener = EventTriggerListener.Get(tra.transform);
            Vector3 offset = Vector3.zero;
            Button btn = tra.transform.GetComponent<Button>();
            listener.onBeginDrag += (go) =>
            {
                if (!canTouch)
                    return;  
offset = tra.transform.position - Input.mousePosition;
                if (btn != null)
                {
                    btn.enabled = false;
                }
              
            };
            listener.onDrag += (go) =>
            {
                if (!canTouch)
                    return;
                tra.transform.position = Input.mousePosition + offset;
                DragRangeLimit(tra.transform);
            };
            listener.onEndDrag += (go) =>
            {
                if (!canTouch)
                    return;
                if (btn != null)
                {
                    btn.enabled = true;
                }
            };
        }
    }
}

这样就可以丝滑般流畅可以根据canTouch控制是否可以拖动

GIF.gif

源码地址
https://github.com/1004019267/ScorwViewMoveAndDragUI