Unity中moveType设为1后FixedUpdate内if语句未触发问题

问题详情 #

• 在主移动脚本SnakeMovement顶部声明私有整型变量moveType并初始化为0
• 创建HorizontalMovement函数，通过UI文本按钮的OnClick事件绑定触发；点击后moveType会被设为1，预期触发FixedUpdate()中的if(moveType == 1)分支，允许玩家用A、D键控制移动
• 实际测试中moveType成功变为1，但该if分支逻辑未生效
• 相同机制的MouseMovement（对应moveType=2）可正常工作，唯一区别是鼠标控制有额外的MousePosition脚本辅助
• 单独测试if(moveType == 1)内的代码功能正常，已尝试将HorizontalMovement()和FixedUpdate()设为public、序列化moveType监控值，均未解决问题

附相关脚本 #

MousePosition脚本

public class MousePosition : MonoBehaviour
{
    private Camera mainCam;

    private void Start()
    {
        mainCam = Camera.main;
    }

    private void FixedUpdate()
    {
        Vector2 mouseWorldPosition = mainCam.ScreenToWorldPoint(Input.mousePosition);
        transform.position = mouseWorldPosition;
    }
}

SnakeMovement脚本

public class SnakeMovement : MonoBehaviour
{
    public SnakeTail tail;

    [SerializeField] private GameObject moveObjScreen;
    [SerializeField] private GameObject mouse;
    private Camera mainCam;

    [SerializeField] private float speed;
    private float rotateSpeed;
    private float velocityX = 0f;
    private int moveType = 0;

    void Start()
    {
        Time.timeScale = 0;
        mainCam = Camera.main;
    }

    void Update()
    {
        if (Input.GetKeyDown(KeyCode.LeftShift))
        {
            speed = 4.5f;
        }

        if (Input.GetKeyUp(KeyCode.LeftShift))
        {
            speed = 3f;
        }
    }
    void FixedUpdate()
    {
        if (moveType == 1)
        {
            // Move Type
            velocityX = Input.GetAxisRaw("Horizontal");

            // Movement
            transform. Translate(Vector2.up * speed * Time.fixedDeltaTime, Space.Self);

            // Rotation
            transform.Rotate(Vector3.forward * -velocityX * rotateSpeed * Time.fixedDeltaTime);
        }

        else if (moveType == 2)
        {
            FollowMousePosition();
        }
    }

    void HorizontalMovement()
    {
        Cursor.lockState = CursorLockMode.Locked;
        moveObjScreen.SetActive(false);
        Time.timeScale = 1;
        moveType = 1;
    }

    private void MouseMovement()
    {
        Cursor.visible = false;
        moveObjScreen.SetActive(false);
        mouse.SetActive(true);
        Time.timeScale = 1;
        moveType = 2;
    }

    private void FollowMousePosition()
    {
        // Movement & Rotation
        transform.position = Vector2.MoveTowards(transform.position, GetWorldPositionFromMouse(), speed * Time.deltaTime);
    }

    private Vector2 GetWorldPositionFromMouse()
    {
        return (mainCam.ScreenToWorldPoint(Input.mousePosition));
    }
}

排查与解决方法 #

1. 修复未初始化变量与语法隐患
   rotateSpeed仅声明未赋值，默认值为0导致旋转逻辑完全失效；同时移动代码中transform. Translate存在多余空格（语法隐患）。修改如下：

   // 在SnakeMovement的Start方法中添加rotateSpeed初始化
   void Start()
   {
       Time.timeScale = 0;
       mainCam = Camera.main;
       rotateSpeed = 120f; // 按需调整数值
   }
   
   // 修正FixedUpdate中的移动代码
   transform.Translate(Vector2.up * speed * Time.fixedDeltaTime, Space.Self);
   

2. 验证输入与时间缩放
   在FixedUpdate中添加调试日志，确认moveType和Time.timeScale的实际值，排除其他代码修改时间缩放的可能：

   void FixedUpdate()
   {
       Debug.Log($"moveType: {moveType}, Time.timeScale: {Time.timeScale}");
       // 原有逻辑...
   }
   

3. 确认输入轴配置
   检查Unity编辑器的Edit > Project Settings > Input Manager，确保Horizontal轴已正确绑定A/D（或左/右箭头）键，避免输入无响应。

内容的提问来源于stack exchange，提问作者Leo Sharpe