1.搖桿父物體設定Anchor，在左邊設定左左下邊，在右邊設定右下角：

2.建立搖桿，設定前置圖片和背景圖在同一物體下，給背景圖新增碰撞體和指令碼，並且設定前置圖片：

程式碼：

using UnityEngine;
using System;

public class GameRocker : MonoBehaviour {

    private static GameRocker _instance;
    public static GameRocker Instance
    {
        get { return _instance; }
    }

    private
 
 UIRoot UIRoot { get; set; }

    /// <summary>
    /// 開始使用搖桿
    /// </summary>
    public Action OnRockerStart;
    /// <summary>
    /// 停止使用搖桿
    /// </summary>
    public Action OnRockerEnd;
    /// <summary>
    /// 當搖桿使用中
    /// </summary>
    public Action<Vector2> OnRockeRun; 

    ///
 
 <summary>
    /// 搖桿前置點
    /// </summary>
    public Transform RockerForward;

    /// <summary>
    /// 搖桿前置點範圍
    /// </summary>
    public float PointRange = 50;

    /// <summary>
    /// 是否為定點搖桿
    /// </summary>
    public bool IsFixedPoint = false;
    /// <summary>
    /// 預設搖桿座標
 

    /// </summary>
    private Vector3 defalutPos = Vector3.zero;

    private bool IsPress = false;
    /// <summary>
    /// 是否在右側
    /// </summary>
    public bool IsRight = false;

    private BoxCollider BoxCollider { get; set; }
    /// <summary>
    /// 手指ID
    /// </summary>
    private int fingerId = -1;
    /// <summary>
    /// 螢幕比例
    /// </summary>
    private float SceneRatio = 0;
    /// <summary>
    /// 世界座標
    /// </summary>
    private Vector2 worldPos = Vector2.zero;

    private string State = "";

    void Awake()
    {
        _instance = this;
        BoxCollider = this.GetComponent<BoxCollider>();

        UIRoot = GameObject.FindObjectOfType<UIRoot>();
    }

    void Start()
    {
        defalutPos = transform.localPosition;
        SceneRatio = Screen.height / (float)Screen.width ;
        worldPos.y = UIRoot.manualHeight;
        worldPos.x = (int)(worldPos.y / SceneRatio);
        RockerForward.localPosition = transform.localPosition;
    }

    void OnPress(bool isPress)
    {
        if (isPress)
            OnStart();
        else
            OnEnd();
        IsPress = isPress;
    }

    void Update()
    {
        if (IsPress)
            OnRun();
    }

    private void OnStart()
    {
        ///pc
        if (Application.platform != RuntimePlatform.WindowsEditor && Application.platform != RuntimePlatform.WindowsPlayer)
        {
            if (fingerId == -1)
            {
                //int touchCount = Input.touchCount;
                for (int i = 0; i < Input.touchCount; i++)
                {
                    Touch touchInfo = Input.GetTouch(i);
                    //拍段touch點位置
                    if (IsTheRange(touchInfo.position))
                    {
                        if (!IsFixedPoint)
                            transform.localPosition = PosConversion(touchInfo.position);
                        fingerId = touchInfo.fingerId;
                        break;
                    }
                }
                State = "Start";
            }
        }
        else
        {
            if (!IsFixedPoint)
                transform.localPosition = PosConversion(UICamera.lastTouchPosition);
        }

        RockerForward.localPosition = transform.localPosition;

        if (OnRockerStart != null)
            OnRockerStart();
    }

    private void OnEnd()
    {
        fingerId = -1;
        if (!IsFixedPoint)
        {
            transform.localPosition = defalutPos;
            //RockerForward.localPosition = transform.localPosition;
        }
        RockerForward.localPosition = transform.localPosition;
        if (OnRockerEnd != null)
            OnRockerEnd();
        State = "End";

    }
    private float time = 0;
    private string error = "";
    private void OnRun()
    {
        try
        {
            error = "";
            time += Time.deltaTime;
            //pc
            Vector3 TargetPos = Vector3.zero;
            if (Application.platform == RuntimePlatform.WindowsEditor || Application.platform == RuntimePlatform.WindowsPlayer)
                TargetPos = PosConversion(UICamera.lastTouchPosition);
            else//手機
            {
                Touch touchInfo = GetTouch(fingerId);
                TargetPos = PosConversion(touchInfo.position);
            }

            if (TargetPos == transform.localPosition) return;
            State = "Run";
            //if (IsIgnore(TargetPos)) return;
            //計算方向
            Vector3 rockerDir = TargetPos - transform.localPosition;
            //執行事件
            if (OnRockeRun != null)
                OnRockeRun(rockerDir.normalized);

            //如果開啟了範圍限定
            if (PointRange != -1)
            {
                float dis = Vector3.Distance(TargetPos, transform.localPosition);
                if (dis > PointRange)
                {
                    Vector3 pointPos = rockerDir.normalized * PointRange;
                    RockerForward.localPosition = transform.localPosition + pointPos;
                    return;
                }
                RockerForward.transform.localPosition = TargetPos;
            }
        }
        catch (Exception ce)
        {
            error = ce.Message;
            fingerId = -1;
            OnStart();
        }
    }

    /// <summary>
    /// 座標轉
    /// </summary>
    Vector3 PosConversion(Vector2 pos)
    {
        Vector2 newPos = Vector2.zero;
        float heightRatio = pos.y / Screen.height;
        newPos.y = heightRatio * worldPos.y;
        float widthRatio = pos.x / Screen.width;
        newPos.x = widthRatio * worldPos.x;
        if (IsRight)
        {
            newPos.x = -(worldPos.x- newPos.x);
        }
        return newPos;
    }

    bool IsTheRange(Vector2 pos)
    {
        pos = PosConversion(pos);
        Vector2 topPoint = new Vector2(transform.localPosition.x+BoxCollider.size.x/2,transform.localPosition.y+BoxCollider.size.y/2);
        Vector2 downPoint = new Vector2(transform.localPosition.x - BoxCollider.size.x / 2, transform.localPosition.y - BoxCollider.size.y / 2);
        if (pos.x < topPoint.x && pos.x > downPoint.x && pos.y < topPoint.y && pos.y > downPoint.y)
            return true;

        return false;
    }

    Touch GetTouch(int TouchID)
    {
        for (int i = 0; i < Input.touchCount; i++)
        {
            if (Input.touches[i].fingerId.Equals(TouchID))
                return Input.touches[i];
        }
        return default(Touch);
    }

    string des = "";
    void OnGUI()
    {
        GUI.color = Color.red;
        des = "";
        des += "Count:" + Input.touchCount + "\n";
        for (int i = 0; i < Input.touchCount; i++)
        {
            des += "id:" + Input.touches[i].fingerId + " pos:" + Input.touches[i].position + " delayPos:" + Input.touches[i].deltaPosition + "\n";
        }
        des += "CurJoyPos:" + transform.localPosition+"\n";
        des += "FingerId:" + fingerId+"\n";
        des += "IsPress:" + IsPress+"\n";
        des += "Time:" + time+"\n";
        des += "State:" + State+"\n";
        des += "Error:" + error;
        GUILayout.Label(des);

    }


}