Unity3D碰撞总是返回True

Question

我希望make状态在跳转时不能使用Space，但是当我make时，冲突只会返回True。我尝试使用RayCast进行测试，即使检测到null仍返回true。

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

public class movement : MonoBehaviour
{
public float speed;
public float jump_height;
Rigidbody2D PlayerRig;
public GameObject Spawner;
// Use this for initialization
void Start()
{

}

private void Awake()
{
    PlayerRig = gameObject.GetComponent<Rigidbody2D>();
}

// Update is called once per frame
void Update()
{
    float Move = Input.GetAxis("Horizontal") * speed;
    gameObject.transform.Translate(new Vector3(Move, 0, 0) * Time.deltaTime);
    if (Input.GetKeyDown(KeyCode.Space) && isTouching() == true)
    {
        Jump();
    }
}

void Jump()
{
    PlayerRig.AddForce(Vector2.up * jump_height);
}

bool isTouching()
{
    RaycastHit2D hit = Physics2D.Raycast(transform.position, Vector2.down, 0.1f);
    if (hit)
    {
        return true;
    }
    else
        return false;
}
}

由于CollisionEnter / Stay也无法正常工作，仍然只返回true