在Unity3D中拖拽ScrollRect（ScrollView）

Question

我想在滚动视图的内容上实现拖放。

问题是当您尝试在滚动视图中拖动项目时无法滚动视图。

首先，我尝试通过IDragHandler、IBeginDragHandler、IEndDragHandle 和IDropHandler 接口实现拖放。乍一看，它工作得很好，但问题是你不能滚动 ScrollRect。

我认为问题是因为覆盖，当我使用与滚动矩形相同的事件触发器时，如拖动，父触发器无法正常工作。

所以后来自己想了想，通过IPointerDown、IPointerUp接口和ScrollRect中拖拽的具体时间UI实现，具体时间不按住滚动效果很好。

但问题是启用我在 OnDrag、OnBeginDrag 和 OnEndDrag 函数之前编写的 DragHandler 脚本在保持时间结束时不起作用。

首先我想知道有什么方法可以调用这些函数？

其次有什么方法可以实现拖放 UI 而不使用拖动界面？

拖动处理程序：

using System;
using UnityEngine;
using UnityEngine.EventSystems;

public class DragHandler : MonoBehaviour, IDragHandler, IBeginDragHandler, IEndDragHandler
{
    public static GameObject itemBeingDragged;

    private Vector3 startPos;

    private Transform startParent;

    DragHandler dragHandler;

    public void Awake()
    {
        dragHandler = GetComponent<DragHandler>();
    }

    public void OnBeginDrag(PointerEventData eventData)
    {
        Debug.Log("Begin");
        itemBeingDragged = gameObject;
        startPos = transform.position;
        startParent = transform.parent;
    }

    public void OnDrag(PointerEventData eventData)
    {
        Debug.Log("Drag");
        transform.position = Input.mousePosition;
    }

    public void OnEndDrag(PointerEventData eventData)
    {
        Debug.Log("End");
        itemBeingDragged = null;
        if (transform.parent == startParent)
        {
            dragHandler.enabled = false;
            transform.SetParent(startParent);
            transform.position = startPos;
        }
    }
}

滚动矩形控制器：

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

public class ScrollRectController : MonoBehaviour, IPointerDownHandler, IPointerUpHandler
{
    public float holdTime;
    public float maxVelocity;

    private Transform scrollRectParent;

    private DragHandler dragHandler;

    private ScrollRect scrollRect;

    private float timer;

    private bool isHolding;

    void Awake()
    {
        scrollRectParent = GameObject.FindGameObjectWithTag("rec_dlg").transform;
        dragHandler = GetComponent<DragHandler>();
        dragHandler.enabled = false;
    }

    // Use this for initialization
    void Start()
    {
        timer = holdTime;
    }

    // Update is called once per frame
    void Update()
    {

    }

    public void OnPointerDown(PointerEventData eventData)
    {
        Debug.Log("Down");
        scrollRect = scrollRectParent.GetComponent<ScrollRect>();
        isHolding = true;
        StartCoroutine(Holding());
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        Debug.Log("Up");
        isHolding = false;
    }

    IEnumerator Holding()
    {
        while (timer > 0)
        {
            //if (scrollRect.velocity.x >= maxVelocity)
            //{
            //    isHolding = false;
            //}

            if (!isHolding)
            {
                timer = holdTime;
                yield break;
            }

            timer -= Time.deltaTime;
            Debug.Log(timer);
            yield return null;
        }

        dragHandler.enabled = true;
        //dragHandler.OnBeginDrag();
    }
}

插槽：

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

public class Slot : MonoBehaviour, IDropHandler
{
    public void OnDrop(PointerEventData eventData)
    {
        DragHandler.itemBeingDragged.transform.SetParent(transform);
    }
}

Answer 1

答案：

我在不使用 DragHandler 接口的情况下编写了一些处理 scrollRect(scrollView) 中的拖放的代码。

拖动处理程序：

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

public class DragHandler : MonoBehaviour, IPointerExitHandler
{
    public static GameObject itemBeingDragged;

    public static bool isCustomerDragged;

    public Transform customerScrollRect;
    public Transform dragParent;

    public float holdTime;
    public float maxScrollVelocityInDrag;

    private Transform startParent;

    private ScrollRect scrollRect;

    private float timer;

    private bool isHolding;
    private bool canDrag;
    private bool isPointerOverGameObject;

    private CanvasGroup canvasGroup;

    private Vector3 startPos;

    public Transform StartParent
    {
        get { return startParent; }
    }

    public Vector3 StartPos
    {
        get { return startPos; }
    }

    void Awake()
    {
        canvasGroup = GetComponent<CanvasGroup>();
    }

    // Use this for initialization
    void Start()
    {
        timer = holdTime;
    }

    // Update is called once per frame
    void Update()
    {
        if (Input.GetMouseButtonDown(0))
        {
            if (EventSystem.current.currentSelectedGameObject == gameObject)
            {
                //Debug.Log("Mouse Button Down");
                scrollRect = customerScrollRect.GetComponent<ScrollRect>();
                isPointerOverGameObject = true;
                isHolding = true;
                StartCoroutine(Holding());
            }
        }

        if (Input.GetMouseButtonUp(0))
        {
            if (EventSystem.current.currentSelectedGameObject == gameObject)
            {
                //Debug.Log("Mouse Button Up");
                isHolding = false;

                if (canDrag)
                {
                    itemBeingDragged = null;
                    isCustomerDragged = false;
                    if (transform.parent == dragParent)
                    {
                        canvasGroup.blocksRaycasts = true;
                        transform.SetParent(startParent);
                        transform.localPosition = startPos;
                    }
                    canDrag = false;
                    timer = holdTime;
                }
            }
        }

        if (Input.GetMouseButton(0))
        {
            if (EventSystem.current.currentSelectedGameObject == gameObject)
            {
                if (canDrag)
                {
                    //Debug.Log("Mouse Button");
                    transform.position = Input.mousePosition;
                }
                else
                {
                    if (!isPointerOverGameObject)
                    {
                        isHolding = false;
                    }
                }
            }
        }
    }

    public void OnPointerExit(PointerEventData eventData)
    {
        isPointerOverGameObject = false;
    }

    IEnumerator Holding()
    {
        while (timer > 0)
        {
            if (scrollRect.velocity.x >= maxScrollVelocityInDrag)
            {
                isHolding = false;
            }

            if (!isHolding)
            {
                timer = holdTime;
                yield break;
            }

            timer -= Time.deltaTime;
            //Debug.Log("Time : " + timer);
            yield return null;
        }

        isCustomerDragged = true;
        itemBeingDragged = gameObject;
        startPos = transform.localPosition;
        startParent = transform.parent;
        canDrag = true;
        canvasGroup.blocksRaycasts = false;
        transform.SetParent(dragParent);
    }

    public void Reset()
    {
        isHolding = false;
        canDrag = false;
        isPointerOverGameObject = false;
    }
}

对这段代码的一些解释：

您的可拖动 UI 元素需要棘手的选项，对我来说，我使用了按钮。
您需要将此脚本附加到您的可拖动项。
您还需要添加 Canvas 组组件。
customerScrollRect 是您项目的 ScrollRect 父级。
dragParent 可以是一个空的游戏对象，因为视口的掩码而被使用。

插槽：

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

public class Slot : MonoBehaviour, IPointerEnterHandler, IPointerExitHandler
{
    bool isEntered;

    public void OnPointerEnter(PointerEventData eventData)
    {
        isEntered = true;
    }

    public void OnPointerExit(PointerEventData eventData)
    {
        isEntered = false;
    }

    void Update()
    {
        if (Input.GetMouseButtonUp(0))
        {
            if (isEntered)
            {
                if (DragHandler.itemBeingDragged)
                {
                    GameObject draggedItem = DragHandler.itemBeingDragged;
                    DragHandler dragHandler = draggedItem.GetComponent<DragHandler>();
                    Vector3 childPos = draggedItem.transform.position;
                    //Debug.Log("On Pointer Enter");
                    draggedItem.transform.SetParent(dragHandler.StartParent);
                    draggedItem.transform.localPosition = dragHandler.StartPos;
                    draggedItem.transform.parent.SetParent(transform);
                    draggedItem.transform.parent.position = childPos;
                    isEntered = false;
                }
            }
        }
    }
}

对这个脚本的一些解释：

1.Attach 掉落物品的脚本。

Answer 2

我找到了一个更简单的解决方案。也许它必须由特殊需求定制，但是如果你把这个脚本放在你的项目上并进行设置，它应该可以工作。

预制件并不容易，但我让控制器制作了它。我在指定的 GameObject 中找到所有 UIElementDragger 并以编程方式添加所需的 GO 实例。

但如果您不使用预制件，则可以直接使用此代码。

using UnityEngine;
using UnityEngine.EventSystems;

public class UIElementDragger : MonoBehaviour, IPointerUpHandler, IPointerDownHandler
{
    /// <summary>
    /// Offset in pixels horizontally (positive to right, negative to left)
    /// </summary>
    [Range(40, 100)]
    public float offsetX = 40;

    /// <summary>
    /// Offset in pixels vertically (positive to right, negative to left)
    /// </summary>
    [Range(40, 100)]
    public float offsetY = 40;

    /// <summary>
    /// The Panel where the item will set as Child to during drag
    /// </summary>
    public Transform parentRect;

    /// <summary>
    /// The GameObject where the item is at start
    /// </summary>
    public Transform homeWrapper;

    /// <summary>
    /// The Object where the mouse must be when pointer is up, to put it in this panel
    /// </summary>
    public Transform targetRect;

    /// <summary>
    /// The GameObject where the item should live after dropping
    /// </summary>
    public Transform targetWrapper;

    private int siblingIndex;
    private bool dragging;

    private void Start()
    {
        siblingIndex = transform.GetSiblingIndex();
    }

    private void Update()
    {
        if (dragging)
        {
            transform.position = new Vector2(Input.mousePosition.x + offsetX, Input.mousePosition.y + offsetY);
        }
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        transform.parent = parentRect;
        dragging = true;
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        if (eventData.pointerCurrentRaycast.gameObject.transform.IsChildOf(targetRect))
        {
            transform.parent = targetWrapper;
        }
        else
        {
            transform.parent = homeWrapper;
            transform.SetSiblingIndex(siblingIndex);
        }

        dragging = false;
    }
}

Answer 3

这个问题最简单的解决方案实际上是手动调用 ScrollRect 的 事件 IF 用户没有按下足够长的时间使用 ExecuteEvents.Execute。此解决方案的附加代码量最少。

using System.Collections;
using UnityEngine;
using UnityEngine.Events;
using UnityEngine.EventSystems;
using UnityEngine.UI;

public class DragAndDropHandler : MonoBehaviour, IPointerDownHandler, IPointerUpHandler, IPointerExitHandler, IDragHandler, IBeginDragHandler, IEndDragHandler
{
    // Don't forget to set this to TRUE or expose it to the Inspector else it will always be false and the script will not work
    public bool Draggable { get; set; }

    private bool draggingSlot;

    [SerializeField] private ScrollRect scrollRect;

    public void OnPointerDown(PointerEventData eventData)
    {
        if (!Draggable)
        {
            return;
        }

        StartCoroutine(StartTimer());
    }

    public void OnPointerExit(PointerEventData eventData)
    {
        StopAllCoroutines();
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        StopAllCoroutines();
    }

    private IEnumerator StartTimer()
    {
        yield return new WaitForSeconds(0.5f);
        draggingSlot = true;
    }

    public void OnBeginDrag(PointerEventData eventData)
    {
        ExecuteEvents.Execute(scrollRect.gameObject, eventData, ExecuteEvents.beginDragHandler);
    }

    public void OnDrag(PointerEventData eventData)
    {
        if (draggingSlot)
        {
            //DO YOUR DRAGGING HERE
        } else
        {
            //OR DO THE SCROLLRECT'S
            ExecuteEvents.Execute(scrollRect.gameObject, eventData, ExecuteEvents.dragHandler);
        }
    }

    public void OnEndDrag(PointerEventData eventData)
    {
        ExecuteEvents.Execute(scrollRect.gameObject, eventData, ExecuteEvents.endDragHandler);
        if (draggingSlot)
        {
            //END YOUR DRAGGING HERE
            draggingSlot = false;
        }
    }
}

Answer 4

这是我的解决方案，谢谢大家。

我必须使用假实例来保留对象，即使您将它移到列表中也是如此。我 post 一个垂直和一个水平的解决方案。希望对你有帮助

using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

public class DragController : MonoBehaviour, IPointerDownHandler, IDragHandler, IPointerUpHandler
{
    private RectTransform currentTransform;
    private GameObject instancePrefab;
    private GameObject mainContent;
    private Vector3 initialePosition;
    
    private int totalChild;

    void Awake()
    {
        currentTransform = this.GetComponent<RectTransform>();
        mainContent = currentTransform.parent.gameObject;
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        initialePosition = currentTransform.position;
        totalChild = mainContent.transform.childCount;

        if (instancePrefab == null)
        {
            instancePrefab = Instantiate(this.gameObject, mainContent.transform.parent.transform);
            instancePrefab.GetComponent<Image>().enabled = false;
        }
    }

    public void OnDrag(PointerEventData eventData)
    {
        currentTransform.position = new Vector3(eventData.position.x, currentTransform.position.y, currentTransform.position.z);

        if (instancePrefab != null)
        {
            instancePrefab.GetComponent<Image>().enabled = true;
            currentTransform.GetComponent<Image>().enabled = false;

            instancePrefab.transform.position = currentTransform.position;
        }

        for (int i = 0; i < totalChild; i++)
        {
            if (i != currentTransform.GetSiblingIndex())
            {
                Transform otherTransform = mainContent.transform.GetChild(i);
                int distance = (int)Vector3.Distance(currentTransform.position, otherTransform.position);

                if (distance <= 20)
                {
                    Vector3 otherTransformOldPosition = otherTransform.position;
                    // Vertical
                    /*otherTransform.position = new Vector3(otherTransform.position.x, initialePosition.y,
                        otherTransform.position.z);
                    currentTransform.position = new Vector3(currentTransform.position.x, otherTransformOldPosition.y,
                        currentTransform.position.z);*/
                    // Horizontal 
                    otherTransform.position = new Vector3(initialePosition.x, otherTransform.position.y,
                        otherTransform.position.z);
                    currentTransform.position = new Vector3(otherTransformOldPosition.x, currentTransform.position.y,
                        currentTransform.position.z);

                    currentTransform.SetSiblingIndex(otherTransform.GetSiblingIndex());
                    initialePosition = currentTransform.position;
                }
            }
        }
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        currentTransform.position = initialePosition;
        instancePrefab.GetComponent<Image>().enabled = false;
        currentTransform.GetComponent<Image>().enabled = true;
        Destroy(instancePrefab);
        instancePrefab = null;
        
    }
}

在Unity3D中拖拽ScrollRect（ScrollView）

Drag and Drop In ScrollRect (ScrollView) in Unity3D

drag-and-drop

eventtrigger

scrollrect

scrollview

unity3d