请编写一个脚本：在ugui实现类似fairygui里面的关联系统

以下是一个实现类似FairyGUI的关联系统的UGUI脚本：

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

public class UIRelationSystem : MonoBehaviour
{
    public enum RelationType
    {
        None,
        Left,
        Right,
        Top,
        Bottom,
        CenterX,
        CenterY,
    }

    public class RelationInfo
    {
        public RelationType type;
        public int targetId;
        public int targetOffset;
        public bool targetPercent;
    }

    private Dictionary<int, List<RelationInfo>> mRelations = new Dictionary<int, List<RelationInfo>>();

    private RectTransform mRectTrans;

    void Awake()
    {
        mRectTrans = GetComponent<RectTransform>();
    }

    public void AddRelation(RelationType type, int targetId, int targetOffset = 0, bool targetPercent = false)
    {
        if (!mRelations.ContainsKey(targetId))
        {
            mRelations.Add(targetId, new List<RelationInfo>());
        }

        List<RelationInfo> relations = mRelations[targetId];

        RelationInfo info = new RelationInfo();
        info.type = type;
        info.targetId = targetId;
        info.targetOffset = targetOffset;
        info.targetPercent = targetPercent;

        relations.Add(info);
    }

    public void RemoveRelation(int targetId)
    {
        if (mRelations.ContainsKey(targetId))
        {
            mRelations.Remove(targetId);
        }
    }

    void Update()
    {
        foreach (KeyValuePair<int, List<RelationInfo>> kvp in mRelations)
        {
            RectTransform targetRectTrans = GetRectTransform(kvp.Key);

            if (targetRectTrans != null)
            {
                foreach (RelationInfo info in kvp.Value)
                {
                    switch (info.type)
                    {
                        case RelationType.Left:
                            SetLeft(targetRectTrans, info.targetOffset, info.targetPercent);
                            break;
                        case RelationType.Right:
                            SetRight(targetRectTrans, info.targetOffset, info.targetPercent);
                            break;
                        case RelationType.Top:
                            SetTop(targetRectTrans, info.targetOffset, info.targetPercent);
                            break;
                        case RelationType.Bottom:
                            SetBottom(targetRectTrans, info.targetOffset, info.targetPercent);
                            break;
                        case RelationType.CenterX:
                            SetCenterX(targetRectTrans, info.targetOffset, info.targetPercent);
                            break;
                        case RelationType.CenterY:
                            SetCenterY(targetRectTrans, info.targetOffset, info.targetPercent);
                            break;
                    }
                }
            }
        }
    }

    private RectTransform GetRectTransform(int id)
    {
        GameObject go = GameObject.Find("UIObject" + id);
        if (go != null)
        {
            return go.GetComponent<RectTransform>();
        }
        return null;
    }

    private void SetLeft(RectTransform target, int offset, bool percent)
    {
        float x = target.anchoredPosition.x - target.rect.width / 2 - mRectTrans.rect.width / 2;
        if (percent)
        {
            x *= 100 / mRectTrans.rect.width;
        }
        mRectTrans.anchoredPosition = new Vector2(x - offset, mRectTrans.anchoredPosition.y);
    }

    private void SetRight(RectTransform target, int offset, bool percent)
    {
        float x = target.anchoredPosition.x + target.rect.width / 2 + mRectTrans.rect.width / 2;
        if (percent)
        {
            x *= 100 / mRectTrans.rect.width;
        }
        mRectTrans.anchoredPosition = new Vector2(x + offset, mRectTrans.anchoredPosition.y);
    }

    private void SetTop(RectTransform target, int offset, bool percent)
    {
        float y = target.anchoredPosition.y + target.rect.height / 2 + mRectTrans.rect.height / 2;
        if (percent)
        {
            y *= 100 / mRectTrans.rect.height;
        }
        mRectTrans.anchoredPosition = new Vector2(mRectTrans.anchoredPosition.x, y + offset);
    }

    private void SetBottom(RectTransform target, int offset, bool percent)
    {
        float y = target.anchoredPosition.y - target.rect.height / 2 - mRectTrans.rect.height / 2;
        if (percent)
        {
            y *= 100 / mRectTrans.rect.height;
        }
        mRectTrans.anchoredPosition = new Vector2(mRectTrans.anchoredPosition.x, y - offset);
    }

    private void SetCenterX(RectTransform target, int offset, bool percent)
    {
        float x = target.anchoredPosition.x;
        if (percent)
        {
            x *= 100 / mRectTrans.rect.width;
        }
        mRectTrans.anchoredPosition = new Vector2(x + offset, mRectTrans.anchoredPosition.y);
    }

    private void SetCenterY(RectTransform target, int offset, bool percent)
    {
        float y = target.anchoredPosition.y;
        if (percent)
        {
            y *= 100 / mRectTrans.rect.height;
        }
        mRectTrans.anchoredPosition = new Vector2(mRectTrans.anchoredPosition.x, y + offset);
    }
}

这个脚本可以作为UI元素上的组件添加。通过调用AddRelation方法来添加关系，通过传入类型、目标UI元素的ID、偏移量和是否按百分比来指定关系。例如：

UIRelationSystem relation = myElement.AddComponent<UIRelationSystem>();
relation.AddRelation(UIRelationSystem.RelationType.Left, 1, 10, false);
relation.AddRelation(UIRelationSystem.RelationType.CenterY, 2, 0, true);

以上代码将在myElement上添加两个关系，一个是左边与ID为1的UI元素间隔10个像素，另一个是竖直居中于ID为2的UI元素。更新时，脚本将根据每个关系的类型和偏移量来计算新的位置。