c# - 修复 Unity 中的 ScrollRect 多点触控？

Question

目前，ScrollRect 在移动设备上的多点触控方面存在严重缺陷。

如果您自己尝试一下，您会发现只要将两根手指放在屏幕上，内容就会跳来跳去，并产生一些意想不到的行为。

有什么解决办法吗？目前，this是我找到的唯一解决方案，但在某些情况下它仍然存在问题，最重要的是，它无法确定屏幕上所有手指的平均输入位置(或 MultiTouchPosition)。

这是我对 UnityUIExtensions bitbucket 中的 MultiTouchScrollRect.cs 脚本的修改版本，但每次我将下一个手指放在屏幕上时它都会跳转:

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

public class MultiTouchScrollRect : ScrollRect
{
    private int minimumTouchCount = 1, maximumTouchCount = 2, pointerId = -100;

    public Vector2 MultiTouchPosition
    {
        get
        {
            Vector2 position = Vector2.zero;
            for (int i = 0; i < Input.touchCount && i < maximumTouchCount; i++)
            {
                position += Input.touches[i].position;
            }
            position /= ((Input.touchCount <= maximumTouchCount) ? Input.touchCount : maximumTouchCount);
            return position;
        }
    }

    public override void OnBeginDrag(PointerEventData eventData)
    {
        if (Input.touchCount >= minimumTouchCount)
        {
            pointerId = eventData.pointerId;
            eventData.position = MultiTouchPosition;
            base.OnBeginDrag(eventData);
        }
    }
    public override void OnDrag(PointerEventData eventData)
    {
        if (Input.touchCount >= minimumTouchCount)
        {
            eventData.position = MultiTouchPosition;
            if (pointerId == eventData.pointerId)
            {
                base.OnDrag(eventData);
            }
        }
    }
    public override void OnEndDrag(PointerEventData eventData)
    {
        if (Input.touchCount >= minimumTouchCount)
        {
            pointerId = -100;
            eventData.position = MultiTouchPosition;
            base.OnEndDrag(eventData);
        }
    }
}

感谢您的宝贵时间!

Answer 1

对于那些感兴趣的人，这是我编写的解决问题的扩展 ScrollRect 类:

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

namespace DanielLochner.Assets
{
    public class MultiTouchScrollRect : ScrollRect
    {
        #region Fields
        private int minimumTouchCount = 1, maximumTouchCount = 2, initialTouchCount = 0;
        #endregion

        #region Properties
        public Vector2 MultiTouchPosition
        {
            get
            {
                Vector2 position = Vector2.zero;
                for (int i = 0; i < Input.touchCount && i < maximumTouchCount; i++)
                {
                    position += Input.touches[i].position;
                }
                position /= ((Input.touchCount <= maximumTouchCount) ? Input.touchCount : maximumTouchCount);

                return position;
            }
        }
        #endregion

        #region Methods
        private void Update()
        {
            if (SystemInfo.deviceType == DeviceType.Handheld || UnityEditor.EditorApplication.isRemoteConnected)
            {
                if (Input.touchCount > 0)
                {
                    if (initialTouchCount == 0)
                    {
                        initialTouchCount = Input.touchCount;
                    }
                }
                else
                {
                    initialTouchCount = 0;
                }
            }
        }

        public override void OnBeginDrag(PointerEventData eventData)
        {
            if (SystemInfo.deviceType == DeviceType.Handheld || UnityEditor.EditorApplication.isRemoteConnected)
            {
                if (Input.touchCount >= minimumTouchCount && Input.touchCount == initialTouchCount)
                {
                    eventData.position = MultiTouchPosition;
                    base.OnBeginDrag(eventData);
                }
            }
            else if (SystemInfo.deviceType == DeviceType.Desktop)
            {
                base.OnBeginDrag(eventData);
            }
        }
        public override void OnDrag(PointerEventData eventData)
        {
            if (SystemInfo.deviceType == DeviceType.Handheld || UnityEditor.EditorApplication.isRemoteConnected)
            {
                if (Input.touchCount >= minimumTouchCount && Input.touchCount == initialTouchCount)
                {
                    eventData.position = MultiTouchPosition;
                    base.OnDrag(eventData);
                }
            }
            else if (SystemInfo.deviceType == DeviceType.Desktop)
            {
                base.OnDrag(eventData);
            }          
        }
        public override void OnEndDrag(PointerEventData eventData)
        {
            if (SystemInfo.deviceType == DeviceType.Handheld || UnityEditor.EditorApplication.isRemoteConnected)
            {
                if (Input.touchCount >= minimumTouchCount)
                {
                    eventData.position = MultiTouchPosition;
                    base.OnEndDrag(eventData);
                }
            }
            else if (SystemInfo.deviceType == DeviceType.Desktop)
            {
                base.OnEndDrag(eventData);
            }       
        }
        #endregion
    }
}