Unity使用New Input Package无法移动角色的问题求助

我是Unity新手，跟着教程学习，编写了教程42:00处的代码后编译，角色完全无法移动。已严格按照视频步骤操作，但找不到问题所在。

相关版本信息：

• Unity: 2021.3.7f1
• Input System: 1.3.0
• Visual Studio Code Editor: 1.2.5
• Test Framework: 1.1.33

我的代码如下：

using System.Collections;
using System.Collections.Generic;
using UnityEngine.InputSystem;
using UnityEngine;

//Take and handle input and movement from the character
public class PlayerController : MonoBehaviour
{
    public float moveSpeed = 1f;
    public float collisionOffset = 0.05f;
    public ContactFilter2D movementFilter;
    Vector2 movementInput;
    Rigidbody2D rb;
    List<RaycastHit2D> castCollisions = new List<RaycastHit2D>();
    // Start is called before the first frame update
    void Start()
    {
        rb = GetComponent<Rigidbody2D>();
    }

    private void FixedUpdate(){
        //If movement input is not 0, try to move
        if(movementInput != Vector2.zero){
            bool success = TryMove(movementInput);

            if(!success){
                success = TryMove(new Vector2(movementInput.x, 0));
            }

            if(!success){
                success = TryMove(new Vector2(0, movementInput.y));
            }
        }
        
    }

    private bool TryMove(Vector2 direccion){
        //Check for Potencial Collisions
        int count = rb.Cast(
            direccion, // X and Y values between -1 and 1 that represent the direction from the body to look for collision
            movementFilter, // The setting that determines where a collision can occur on such as layers to collide with
            castCollisions, // Lists of collisions to store the found collisions into after the Cast is finished
            moveSpeed = Time.fixedDeltaTime + collisionOffset); // The amount to cast equal to the movement plus an offset

        if(count == 0){
            rb.MovePosition(rb.position * direccion * moveSpeed * Time.fixedDeltaTime);
            return true;
        } else{
            return false;
        }
    }
    void OnMove(InputValue movementValue){
        movementInput = movementValue.Get<Vector2>();
    }

}

问题排查与修正 #

代码里有两处关键错误导致角色无法移动：

1. rb.Cast距离参数的运算符错误
   你使用了赋值运算符=替代乘法运算符*，正确写法应为moveSpeed * Time.fixedDeltaTime + collisionOffset。错误的赋值会把moveSpeed设置为极小值（默认Time.fixedDeltaTime是0.02），后续移动几乎不可见。

2. rb.MovePosition位置计算逻辑错误
   你用乘法rb.position * direccion * ...计算新位置，正确逻辑应该是加法：rb.position + direccion * moveSpeed * Time.fixedDeltaTime。乘法会导致角色位置异常，甚至直接归0，自然无法正常移动。

修正后的TryMove方法：

private bool TryMove(Vector2 direccion){
    //Check for Potencial Collisions
    int count = rb.Cast(
        direccion, 
        movementFilter, 
        castCollisions, 
        moveSpeed * Time.fixedDeltaTime + collisionOffset); 

    if(count == 0){
        rb.MovePosition(rb.position + direccion * moveSpeed * Time.fixedDeltaTime);
        return true;
    } else{
        return false;
    }
}

额外检查项：

• 确保Player对象挂载了Rigidbody2D组件，且Body Type设置为Dynamic，否则MovePosition无法生效。
• 验证Input System输入绑定正确，可在OnMove方法中添加Debug.Log(movementInput)测试输入是否正常接收。

内容的提问来源于stack exchange，提问作者Tomas Iniguez