Unity3D UI,计算拖动物品的位置?

Unity3D UI, calculation for position dragging an item?

如今,在 Unity 中拖动 UI 元素非常容易:制作一些 UI 项目。添加组件 -> 事件 -> 事件触发器。放在下面的脚本上。单击以添加四个明显的触发器。大功告成。

但是

我完全迷失在 指针坐标 UI 坐标 之间的关系中(如 RectTransform 等所示)上)。

在下面的 DragIt 中:你到底是怎么在手指下正确移动 UI 面板的?

假设您有一个大面板,面板中有十个 UI 按钮,按钮上有 Dragster。 RectTransform坐标和鼠标指针有什么关系...

简而言之,您如何在下面的 DragIt() 中移动其中一个按钮?

/* modern Unity drag of UI element */
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.Events;
using UnityEngine.EventSystems;
public class Dragster:MonoBehaviour
    {
    public int index; // number each of your UI items
    static bool beingDragged = false;
    static int dragFrom;
    public void DragStart()
        {
        beingDragged = true; dragFrom = index;
        }
    public void DragIt()
        {
        ? ? W T F ? ?
        }
    public void DragEnd()
        {
        beingDragged = false;
        }
    public void DroppedBra()
        {
        Debig.Log("Drag: from/to " +dragFrom +" --> " +index);
        }
    }

我会让你的脚本实现拖动界面

public class Dragster:MonoBehaviour,IBeginDragHandler, IEndDragHandler, IDragHandler

这将使您的 DragIt 函数变为

public void OnDrag(PointerEventData eventData)
{
    transform.position += (Vector3)eventData.delta;
}

让您可以访问该事件的增量(鼠标移动了多少)以便能够移动您的对象。

如果您仍然宁愿使用 EventTrigger 组件(不太喜欢的方式),您只需将 DragIt 函数更改为 DragIt(PointerEventData eventData) 并使用下拉列表中的 Dynamic EvenData 选项触发器接收 PointerEventData 以访问增量信息


这里实际上是一个完整的拖放“UnityEngine.UI”项目解决方案,基于 Uri 和 Colton 的代码。只需复制和粘贴即可。

用于 Unity UI 的惊人的复制和粘贴,无需动脑筋的完美拖放,wtt Colton 和 Uri:

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

public class UNCDraggable:MonoBehaviour,
IBeginDragHandler, IDragHandler, IEndDragHandler, IDropHandler
    {
    public Image ghost;
    // note DON'T try to drag the actual item: it's not worth the hassle.
    // a problem arises where you can't have it on top (as you would want
    // visually), and still easily get the drops. always use a ghost.
    // even if you want the "original invisible" while dragging,
    // simply hide it and use a ghost. everything is tremendously
    // easier if you do not move the originals.
    
    void Awake()
        {
        ghost.raycastTarget = false;
        // (just in case you forgot to do that in the Editor)
        ghost.enabled = false;
        }
    
    public void OnBeginDrag(PointerEventData eventData)
        {
        ghost.transform.position = transform.position;
        ghost.enabled = true;
        }

    public void OnDrag(PointerEventData eventData)
        {
        ghost.transform.position += (Vector3)eventData.delta;
        }

    public void OnEndDrag(PointerEventData eventData)
        {
        ghost.enabled = false;
        }
    
    public void OnDrop(PointerEventData data)
        {
        GameObject fromItem = data.pointerDrag;
        if (data.pointerDrag == null) return; // (will never happen)
        
        UNCDraggable d = fromItem.GetComponent<UNCDraggable>();
        if (d == null)
          {
          // means something unrelated to our system was dragged from.
          // for example, just an unrelated scrolling area, etc.
          // simply completely ignore these.
          return;
          // note, if very unusually you have more than one "system"
          // of UNCDraggable items on the same screen, be careful to
          // distinguish them! Example solution, check parents are same.
          }
        
        Debug.Log ("dropped  " + fromItem.name +" onto " +gameObject.name);
        
        // your code would look probably like this:
        YourThings fromThing = fromItem.GetComponent<YourButtons>().info;
        YourThings untoThing = gameObject.GetComponent<YourButtons>().info;
        
        yourBossyObject.dragHappenedFromTo(fromThing, untoThing);
        }
    }

对于拖动的东西,我只是这样做:

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

public class Draggable : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler {
    
    
    
    public void OnBeginDrag(PointerEventData eventData) {
        
    }
    
    public void OnDrag(PointerEventData eventData) {
        //Debug.Log ("OnDrag");
        
        this.transform.position = eventData.position;

        }

    public void OnEndDrag(PointerEventData eventData) {
        Debug.Log ("OnEndDrag");
    
    }
}

这是相同的惊人 URIPOPOV 代码,具有两个简单的功能,您在拖动时总是需要这些功能:

// allow dragging with two basic problem fixes:
// - limit drag to the parent box
// - don't "jump" based on where you hold down

100% 测试:

请注意,您必须使用下面#programmer 中的比例转换代码。

using UnityEngine;
using UnityEngine.EventSystems;

public class AmazingUPDrag : MonoBehaviour,
               IBeginDragHandler, IDragHandler, IEndDragHandler
{

RectTransform rt;
Vector2 dragOffset = Vector2.zero;
Vector2 limits = Vector2.zero;

Canvas canvas;

void Awake()
{
    rt = GetComponent<RectTransform>();
    canvas = GetComponentInParent<Canvas>();
}

public void OnBeginDrag(PointerEventData eventData)
{
    dragOffset = ActualPos(eventData.position) - (Vector2)transform.position;
    limits = transform.parent.GetComponent<RectTransform>().rect.max;

    limits.x = limits.x - 100f;
    limits.y = limits.y - 100f;
}

public void OnDrag(PointerEventData eventData)
{
    transform.position = ActualPos(eventData.position) - dragOffset;

    var p = transform.localPosition;
    if (p.x < -limits.x) { p.x = -limits.x; }
    if (p.x > limits.x) { p.x = limits.x; }
    if (p.y < -limits.y) { p.y = -limits.y; }
    if (p.y > limits.y) { p.y = limits.y; }
    transform.localPosition = p;
}

public void OnEndDrag(PointerEventData eventData)
{
    dragOffset = Vector2.zero;
}

Vector2 ActualPos(Vector2 unityDelusionPos)
{
    Vector2 p;
    RectTransformUtility.ScreenPointToLocalPointInRectangle(
        (RectTransform)(canvas.transform),
        unityDelusionPos,
        canvas.worldCamera,
        out p);
    return canvas.transform.TransformPoint(p);
}


}

首先,此 post 中的所有其他答案都非常有效。我为此工作了很长时间,只是想 post 在这里。它增加了一种防止其他不需要的 UI object 被拖来拖去的方法。

我的正式目标是提供一种无需使用 bool beingDragged = false; 即可完成此操作的方法。如果你那样做,你只是不知道 ButtonImage 被拖动了。

拖动UI:

RectTransformUtility 的帮助下将屏幕点转换为 RectTransform 中的本地点,然后使用 Canvas.transform.TransformPoint 找出 child UI 的确切位置。

public Canvas parentCanvasOfImageToMove;
Vector2 pos;
RectTransformUtility.ScreenPointToLocalPointInRectangle(parentCanvasOfImageToMove.transform as RectTransform, eventData.position, parentCanvasOfImageToMove.worldCamera, out pos);
UIToMove.transform.position = parentCanvasOfImageToMove.transform.TransformPoint(pos);

拖动代码看起来比其他答案中的其他拖动代码更复杂,但它似乎在每个 Canvas 相机模式下都有效。

正在检测哪个Object即将被拖动:

最简单的方法是创建一个全局变量,您可以使用它来保存 object 用户想要在 OnBeginDrag 函数中拖动,然后您可以拖动那个 object在 OnDrag。在调用 OnEndDrag 时将 object 设置为 null。

objectToBeDragged = eventData.pointerCurrentRaycast.gameObject;

这必须在 OnBeginDrag 函数中完成一次,然后保存到全局变量中。

您不能在 OnDrag 函数中执行以下操作

if (eventData.pointerCurrentRaycast.gameObject == someOtherUI)
{
   someOtherUI....drag
}

即使它应该有效,但有时却无效。在 OnDrag 期间,它有时甚至 return 为空。这就是为什么它必须在 OnBeginDrag 函数中完成的原因。

检测并拖动按钮与图像:

检测 UI 是否只是一个 Image 并且拖动一个 Image 非常容易。

objectToBeDragged  = eventData.pointerCurrentRaycast.gameObject;
Button tempButton = objectToBeDragged.GetComponent<Button>();
Image tempImage = objectToBeDragged.GetComponent<Image>();

如果 tempImage 而不是 null 并且 tempButtonnull 那么这是一个图像。

检测 UI 是否只是一个 Button 并且拖动 Button 容易。 当在 side/edge 上单击按钮时,Button 的名称是 returned,这很好。但大多数时候,Button 的点击发生在 Button 中间 ,而 而不是 return 按钮的实例或名称,而不是 returns Text(Child Object)。您不能 将文本作为按钮移动。它不会工作。

objectToBeDragged  = eventData.pointerCurrentRaycast.gameObject;
Button tempButton = objectToBeDragged.GetComponent<Button>();
Image tempImage = objectToBeDragged.GetComponent<Image>();
Text tempText = objectToBeDragged.GetComponent<Text>();

如果 tempTextnot null,获取文本的图像和按钮组件的 GetComponentInParent。如果 Image 不为空且 Button 不为空则它是 Button.

if (tempText != null)
{
    tempButton = tempText.GetComponentInParent<Button>();
    tempImage = tempText.GetComponentInParent<Image>();
    if (tempButton != null && tempImage != null)
    {
        //This is a Button
    }
}

下面是拖动UIImage/Panel和Button的完整脚本。应拖动的任何 Button 应放在 UIButtons 数组中,应拖动的任何 Panel/Image 应放在 UIPanels 数组中。它将忽略不在数组中的其他 UI。

public class UIDRAGGER : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{
    public Canvas parentCanvasOfImageToMove;

    //10 UI Buttons (Assign in Editor)
    public Button[] UIButtons;

    //2 UI Panels/Images (Assign in Editor)
    public Image[] UIPanels;

    //Hold which Button or Image is selected
    private Button selectedButton;
    private Image selectedUIPanels;

    //Used to make sure that the UI is position exactly where mouse was clicked intead of the default center of the UI
    Vector3 moveOffset;

    //Used to decide which mode we are in. Button Drag or Image/Panel Mode
    private DragType dragType = DragType.NONE;


    void Start()
    {
        parentCanvasOfImageToMove = gameObject.GetComponent<Canvas>();
    }

    //Checks if the Button passed in is in the array
    bool buttonIsAvailableInArray(Button button)
    {
        bool _isAValidButton = false;
        for (int i = 0; i < UIButtons.Length; i++)
        {
            if (UIButtons[i] == button)
            {
                _isAValidButton = true;
                break;
            }
        }
        return _isAValidButton;
    }

    //Checks if the Panel/Image passed in is in the array
    bool imageIsAvailableInArray(Image image)
    {
        bool _isAValidImage = false;
        for (int i = 0; i < UIPanels.Length; i++)
        {
            if (UIPanels[i] == image)
            {
                _isAValidImage = true;
                break;
            }
        }
        return _isAValidImage;
    }

    void selectButton(Button button, Vector3 currentPos)
    {
        //check if it is in the image array that is allowed to be moved
        if (buttonIsAvailableInArray(button))
        {
            //Make the image the current selected image
            selectedButton = button;
            dragType = DragType.BUTTONS;
            moveOffset = selectedButton.transform.position - currentPos;
        }
        else
        {
            //Clear the selected Button
            selectedButton = null;
            dragType = DragType.NONE;
        }
    }

    void selectImage(Image image, Vector3 currentPos)
    {
        //check if it is in the image array that is allowed to be moved
        if (imageIsAvailableInArray(image))
        {
            //Make the image the current selected image
            selectedUIPanels = image;
            dragType = DragType.IMAGES;
            moveOffset = selectedUIPanels.transform.position - currentPos;
        }
        else
        {
            //Clear the selected Button
            selectedUIPanels = null;
            dragType = DragType.NONE;
        }
    }


    public void OnBeginDrag(PointerEventData eventData)
    {
        GameObject tempObj = eventData.pointerCurrentRaycast.gameObject;

        if (tempObj == null)
        {
            return;
        }

        Button tempButton = tempObj.GetComponent<Button>();
        Image tempImage = tempObj.GetComponent<Image>();
        Text tempText = tempObj.GetComponent<Text>();

        //For Offeset Position
        Vector2 pos;
        RectTransformUtility.ScreenPointToLocalPointInRectangle(parentCanvasOfImageToMove.transform as RectTransform, eventData.position, parentCanvasOfImageToMove.worldCamera, out pos);


        //Button must contain Text then Image and Button as parant
        //Check if this is an image
        if (tempButton == null || tempImage == null)
        {
            //Button not detected. Check if Button's text was detected
            if (tempText != null)
            {
                //Text detected. Now Look for Button and Image in the text's parent Object
                tempButton = tempText.GetComponentInParent<Button>();
                tempImage = tempText.GetComponentInParent<Image>();

                //Since child is text, check if parents are Button and Image
                if (tempButton != null && tempImage != null)
                {
                    //This is a Button
                    selectButton(tempButton, parentCanvasOfImageToMove.transform.TransformPoint(pos));
                }
                //Check if there is just an image
                else if (tempImage != null)
                {
                    //This is an Image
                    selectImage(tempImage, parentCanvasOfImageToMove.transform.TransformPoint(pos));
                }
            }
            else
            {
                //This is an Image
                selectImage(tempImage, parentCanvasOfImageToMove.transform.TransformPoint(pos));
            }
        }
        //Check if there is just an image
        else if (tempImage != null)
        {
            selectImage(tempImage, parentCanvasOfImageToMove.transform.TransformPoint(pos));
        }
    }

    public void OnDrag(PointerEventData eventData)
    {
        Vector2 pos;
        if (dragType == DragType.BUTTONS)
        {
            RectTransformUtility.ScreenPointToLocalPointInRectangle(parentCanvasOfImageToMove.transform as RectTransform, eventData.position, parentCanvasOfImageToMove.worldCamera, out pos);
            selectedButton.transform.position = parentCanvasOfImageToMove.transform.TransformPoint(pos) + moveOffset;
        }
        else if (dragType == DragType.IMAGES)
        {
            RectTransformUtility.ScreenPointToLocalPointInRectangle(parentCanvasOfImageToMove.transform as RectTransform, eventData.position, parentCanvasOfImageToMove.worldCamera, out pos);
            selectedUIPanels.transform.position = parentCanvasOfImageToMove.transform.TransformPoint(pos) + moveOffset;
        }
    }


    public void OnEndDrag(PointerEventData eventData)
    {
        //Buttons
        if (dragType == DragType.BUTTONS || dragType == DragType.IMAGES)
        {
            selectedButton = null;
            selectedUIPanels = null;
            dragType = DragType.NONE;
        }
    }

    DragType getCurrentDragType()
    {
        return dragType;
    }

    private enum DragType { NONE, BUTTONS, IMAGES };
}

好的,所以第一个解决方案适用于 UI 个元素(覆盖 Canvas) 来自@programmer 的那个也适用于其他 Canvases,但对我的使用有一点开销。所以在这里我提取了我认为你需要拖动“当前对象”的最小值

using UnityEngine.EventSystems;

public class SomeObject : MonoBehaviour, IBeginDragHandler, IDragHandler
{
  private Canvas parentCanvas;
  private Vector3 moveOffset;

  void Start()
  {
      // get the "nearest Canvas"
      parentCanvas = GetComponentsInParent<Canvas>()[0];
      // you could get the Camera of this Canvas here as well and like @ina suggests add a null check for that and otherwise use Camera.Main
  }
  public void OnBeginDrag(PointerEventData eventData)
  {

      //For Offset Position so the object won't "jump" to the mouse/touch position
      RectTransformUtility.ScreenPointToLocalPointInRectangle(parentCanvas.transform as RectTransform, eventData.position, parentCanvas.worldCamera, out Vector2 pos);
      moveOffset = transform.position - parentCanvas.transform.TransformPoint(pos);

  }

  public void OnDrag(PointerEventData eventData)
  {
      RectTransformUtility.ScreenPointToLocalPointInRectangle(parentCanvas.transform as RectTransform, eventData.position, parentCanvas.worldCamera, out Vector2 pos);
      transform.position = parentCanvas.transform.TransformPoint(pos) + moveOffset;
  }
}

代码由从我的 class 中抓取的行组成,因此它不是经过测试的脚本。当然你需要一些使用