using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;
 
public class Joystick : ScrollRect
{
 private float mRadius;
 public System.Action<RectTransform> JoystickMoveHandle;
 public System.Action<RectTransform> JoystickEndHandle;
 
 protected override void Start()
 {
  mRadius = this.GetComponent<RectTransform>().sizeDelta.x * 0.5f;
  this.content.gameObject.SetActive(false);
 }
 
 
 public override void OnDrag(PointerEventData eventData)
 { 
  base.OnDrag(eventData);
  this.content.gameObject.SetActive(true);
 
  //虛擬搖桿移動
  var contentPostion = this.content.anchoredPosition;  
  if (contentPostion.magnitude > mRadius)
  {
   contentPostion = contentPostion.normalized * mRadius;
   SetContentAnchoredPosition(contentPostion);
  }
  //旋轉(zhuǎn)
  if (content.anchoredPosition.y != 0)
  {
   content.eulerAngles = new Vector3(0, 0, Vector3.Angle(Vector3.right, content.anchoredPosition) * content.anchoredPosition.y / Mathf.Abs(content.anchoredPosition.y) - 90);
  }
 
 }
 
 private void FixedUpdate()
 {
  if (this.content.gameObject.activeInHierarchy)
  {
   if (JoystickMoveHandle != null)
   {
    JoystickMoveHandle(this.content);
   }
  }
 }
 
 public override void OnEndDrag(PointerEventData eventData)
 {
  base.OnEndDrag(eventData);
 
  this.content.gameObject.SetActive(false);
 
  if (JoystickEndHandle != null)
  {
   JoystickEndHandle(this.content);
  }
 }
}

mJoystick = GameObject.Find("Joystick").GetComponent<Joystick>();
  mJoystick.JoystickMoveHandle = JoystickHandle;
  mJoystick.JoystickEndHandle = JoystickEndHandle;

transform.eulerAngles = new Vector3(0, -content.eulerAngles.z, 0);
 transform.Translate(Vector3.forward * Time.deltaTime * mMoveSpeed);