一，在角色下新增一個空物體

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

public class PlayerController : MonoBehaviour {

    private Rigidbody2D m_rg;

    public float MoveSpeed;
    public float JumpSpeed;

    //在角色下新增一個空物體
    //設定一個跳躍監測點
    public Transform CheckPoint;
    
 
//設定一個跳躍監測半徑
    public float CheckRadius;
    //設定一個跳躍監測層---角色與地面的檢測
    public LayerMask WhatIsGround;

    //角色預設是否著地--true
    public bool isGround;

    private Animator Anim;


    void Start () {

        m_rg = gameObject.GetComponent<Rigidbody2D>();
        Anim = gameObject.GetComponent<Animator>();
    }
    
    
 
// Update is called once per frame
    void Update () {
        //
        isGround = Physics2D.OverlapCircle(CheckPoint.position, CheckRadius, WhatIsGround);


        //------------------Input.GetAxisRaw沒有小數值，只有整數，不會產生緩動------------------
        //角色水平移動
        //按住D鍵，判斷如果大於0，則向右開始移動
        if (Input.GetAxisRaw("
 
Horizontal") > 0)
        {
            m_rg.velocity = new Vector2(MoveSpeed, m_rg.velocity.y);

            //設定自身縮放的值
            transform.localScale = new Vector2(1f,1f);
        }
        //角色水平移動
        //按住A鍵，判斷如果小於0，則向左開始移動
        else if (Input.GetAxisRaw("Horizontal") < 0)
        {
            m_rg.velocity = new Vector2(-MoveSpeed, m_rg.velocity.y);

            //如果new Vector2(-1f, 1f)  x值為負數，則圖片進行反轉顯示
            transform.localScale = new Vector2(-1f, 1f);
        }
        else
        //角色水平移動
        //鬆開按鍵，判斷如果等於0，則停止移動
        {
            m_rg.velocity = new Vector2(0, m_rg.velocity.y);
        }

        //角色按下空格鍵實現跳躍
        //禁止二連跳
        //要先判斷角色是否在地面上，在地面上可以跳，不在地面上則不能跳
        if (Input.GetButtonDown("Jump")&& isGround)
        {

            m_rg.velocity = new Vector2(m_rg.velocity.x,JumpSpeed);
        }


        Anim.SetFloat("Speed", m_rg.velocity.x);
        Anim.SetBool("Grouned", isGround);
    }
}