Unity Error: UnityEngine.Component' does not contain a definition for `velocity'

Question

我是 C# 的新手，如果这很明显，请原谅我。

我正在按照 this tutorial 中的步骤进行操作，并且运行在第六步遇到了问题。它给出的错误是这样的：它给出的错误是这样的：

UnityEngine.Component' does not contain a definition for `velocity' and no extension method `velocity' of type `UnityEngine.Component' could be found. Are you missing an assembly reference?'

代码如下：

using UnityEngine;
using System.Collections;

public class RobotController : MonoBehaviour {
//This will be our maximum speed as we will always be multiplying by 1
public float maxSpeed = 2f;
//a boolean value to represent whether we are facing left or not
bool facingLeft = true;
//a value to represent our Animator
Animator anim;
// Use this for initialization
void Start () {
  //set anim to our animator
  anim = GetComponent<Animator>();

}

// Update is called once per frame
void FixedUpdate () {

  float move = Input.GetAxis ("Horizontal");//Gives us of one if we are moving via the arrow keys
  //move our Players rigidbody
  rigidbody2D.velocity = new Vector3 (move * maxSpeed, rigidbody2D.velocity.y);
  //set our speed
  anim.SetFloat ("Speed",Mathf.Abs (move));
  //if we are moving left but not facing left flip, and vice versa
  if (move < 0 && !facingLeft) {

   Flip ();
  } else if (move > 0 && facingLeft) {
   Flip ();
  }
}

//flip if needed
void Flip(){
  facingLeft = !facingLeft;
  Vector3 theScale = transform.localScale;
  theScale.x *= -1;
  transform.localScale = theScale;
}
}

错误在第 23 行：

rigidbody2D.velocity = new Vector3 (move * maxSpeed, rigidbody2D.velocity.y);

Answer 1

rigidbody2D 曾经是从 Component 继承的变量，而 MonoBehaviour 是继承的。现在已弃用。

现在，您必须声明它并用 GetComponent<Rigidbody>(); 初始化它，就像您在 Start() 函数中对 Animator(anim) 变量所做的那样。另外，为了不与旧变量混淆，我建议您将 rigidbody2D 重命名为其他名称。在下面的示例代码中，我将其重命名为 rigid2D 并声明它。

如果您不重命名它，您可能会收到一条警告：

Severity Code Description Project File Line Suppression State Warning CS0108 'RobotController.rigidbody2D' hides inherited member 'Component.rigidbody2D'. Use the new keyword if hiding was intended.

public class RobotController: MonoBehaviour
{
    public float maxSpeed = 2f;
    //a boolean value to represent whether we are facing left or not
    bool facingLeft = true;
    //a value to represent our Animator
    Animator anim;

    //Declare rigid2D
    Rigidbody rigid2D;
    // Use this for initialization
    void Start()
    {
        //set anim to our animator
        anim = GetComponent<Animator>();

        //Initialize rigid2D
        rigid2D = GetComponent<Rigidbody>();
    }

    // Update is called once per frame
    void FixedUpdate()
    {

        float move = Input.GetAxis("Horizontal");//Gives us of one if we are moving via the arrow keys
                                                 //move our Players rigidbody
        rigid2D.velocity = new Vector3(move * maxSpeed, rigid2D.velocity.y);
        //set our speed
        anim.SetFloat("Speed", Mathf.Abs(move));
        //if we are moving left but not facing left flip, and vice versa
        if (move < 0 && !facingLeft)
        {

            Flip();
        }
        else if (move > 0 && facingLeft)
        {
            Flip();
        }
    }

    //flip if needed
    void Flip()
    {
        facingLeft = !facingLeft;
        Vector3 theScale = transform.localScale;
        theScale.x *= -1;
        transform.localScale = theScale;
    }
}

Answer 2

你只是在start函数中创建了一个刚体对象，

Rigidbody rigidbody = GetComponent<Rigidbody>();

如果您使用的是 2D 动画，请使用以下代码，

Rigidbody2D rigidbody = GetComponent<Rigidbody2D>();

Unity Error: UnityEngine.Component' does not contain a definition for `velocity'

Unity Error: UnityEngine.Component' does not contain a definition for `velocity'

c#

unity3d

unity3d-2dtools

unity5