Unity 2D：当我按下某个键时更改玩家的重力比例？

Question

我对 unity 和 C# 相当陌生，我试图了解当我按空格键时如何改变我的角色的重力比例。当我调试它时，它说Rigidbody2D.gravityScale不能用作方法。有人可以解释为什么它会带来这个错误以及如何修复它吗？

public class PlayerMovement : MonoBehaviour {

    public float moveSpeed;
    private Rigidbody2D rb2d;
    public float addGrav;

    // Use this for initialization
    void Start () {
        rb2d = GetComponent<Rigidbody2D> ();
    }

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

        //Understanding::: If key pressed down, 
        //Transform - method that manipulates position of object
        //Translate moves transform in direction/distance of translation.
        //transform.Translate(translation);
        if (Input.GetKey (KeyCode.UpArrow)) 
        {
            transform.Translate (Vector2.up * moveSpeed * Time.deltaTime);
        }

        if (Input.GetKey (KeyCode.DownArrow)) 
        {
            transform.Translate (Vector2.down * moveSpeed * Time.deltaTime);
        }

        if (Input.GetKey (KeyCode.LeftArrow)) 
        {
            transform.Translate (Vector2.left * moveSpeed * Time.deltaTime);
        }

        if (Input.GetKey (KeyCode.RightArrow)) 
        {
            transform.Translate (Vector2.right * moveSpeed * Time.deltaTime);
        }

        if(Input.GetKey (KeyCode.Space))
        {
            rb2d.gravityScale (addGrav);
        }
    }
}

Answer 1

rb2d.gravityScale 不是一种方法，它是一个可以为其赋值的字段。

用这个

rb2d.gravityScale = addGrav; //to asign
//other example
rb2d.gravityScale += addGrav; //to add
rb2d.gravityScale -= addGrav; //to substract