简易JoyStick实现

支持按键输入WASD,带有方向指示

     　　　　　　　　　　　　　

 脚本挂在Handle上，其它的设置

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

public class JoyStick : MonoBehaviour,IPointerDownHandler,IEndDragHandler,IDragHandler
{
    private RectTransform rectTransform;
    public RectTransform joyStickBG;
    public Camera uiCamera;
    public RectTransform dirArr;
    public float handleMoveRadius;
    private float dirArrOffset;

    public static Action<Vector2> onVelocityChange;
    public static Action onBeginDrag;
    public static Action onEndDrag;
    public Vector2 moveDirection;
    public bool useKeyBoard = false;
    private void Awake()
    {
        rectTransform = GetComponent<RectTransform>();
        dirArr.gameObject.SetActive(false);
        dirArrOffset = rectTransform.sizeDelta.x * 0.5f;
        

    }
    void Update()
    {
        if (onVelocityChange != null)
        {
            onVelocityChange(moveDirection);
        }
        if (!useKeyBoard)
        {
            return;
        }
        float x= Input.GetAxis("Horizontal");
        float y = Input.GetAxis("Vertical");
        Vector2 input = new Vector2(x, y);
        input = Vector2.ClampMagnitude(input, 1);
        rectTransform.anchoredPosition = input*handleMoveRadius;
        if (input.magnitude>=0.95f)
        {
            if (!dirArr.gameObject.activeSelf)
            {
                dirArr.gameObject.SetActive(true);
            }
            dirArr.localRotation = Quaternion.Euler(new Vector3(0, 0, Mathf.Atan2(input.y, input.x) * Mathf.Rad2Deg));
            dirArr.anchoredPosition = input.normalized * dirArrOffset;
        }
        else
        {
            if (dirArr.gameObject.activeSelf)
            {
                dirArr.gameObject.SetActive(false);
            }
        }
        if (onVelocityChange != null)
        {
            onVelocityChange(input);
        }


    }



    public void OnDrag(PointerEventData eventData)
    {
        Vector2 moveDir;
        RectTransformUtility.ScreenPointToLocalPointInRectangle(joyStickBG, Input.mousePosition, uiCamera, out moveDir);
        if (moveDir.magnitude> handleMoveRadius)
        {
            moveDir = moveDir.normalized * handleMoveRadius;
            if (!dirArr.gameObject.activeSelf)
            {
                dirArr.gameObject.SetActive(true);
              
            }
            dirArr.localRotation = Quaternion.Euler(new Vector3(0, 0, Mathf.Atan2(moveDir.y, moveDir.x) * Mathf.Rad2Deg));
            dirArr.anchoredPosition = moveDir.normalized * dirArrOffset;
        }
        else
        {
            if (dirArr.gameObject.activeSelf)
            {
                dirArr.gameObject.SetActive(false);
            }
        }
        rectTransform.anchoredPosition = moveDir;
        moveDirection = moveDir.normalized;


    }

    public void OnEndDrag(PointerEventData eventData)
    {
        rectTransform.anchoredPosition = Vector2.zero;
        dirArr.anchoredPosition = Vector2.zero;
        moveDirection = Vector2.zero;
        dirArr.gameObject.SetActive(false);
        if (onEndDrag!=null)
        {
            onEndDrag();
        }
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        if (onBeginDrag != null)
        {
            onBeginDrag();
        }
    }
}