Here I am trying to change the value of DirectionX when I press a space it works but I have to press more than once to change.

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

public class Player_Movement_script : MonoBehaviour
{
    public float moveSpeed = 1f;
    public float DirectionX=1;
     
    Vector2 DirectionMovement;
   

    void FixedUpdate()
    {

        if (Input.GetKey(KeyCode.Space))
        {
            if (DirectionX > 0)
            {
                DirectionX = -1;
            }
            else if (DirectionX <0)
            {
                DirectionX = 1;
            }
        }
        DirectionMovement = new Vector2(DirectionX, 1f);

        transform.Translate(DirectionMovement * moveSpeed * Time.deltaTime);
    }
}

CodePudding user response：

Three points:

• You rather want to use GetKeyDown which is true only once per key press.

  Otherwise your key press might get tracked twice so you immediately change the direction back again.

• you should get single event user input in Update in order to not miss a frame.

• And then as soon as there is physics involved - which I guess since you use FixedUpdate rather do not use Transform at all but rather go through the Rigodbody2D component

So something like

[SerializeField] private Rigidbody2D _rigidbody;

void Awake ()
{
    if(!_rigidbody) _rigidbody = GetComponent<Rigidbody2D>();
}

void Update ()
{
    if (Input.GetKeyDown(KeyCode.Space))
    {
        DirectionX *= -1; 
    }   
}

void FixedUpdate()
{
    // Only overwrite the X velocity!
    var velocity = _rigidbody.velocity;
    velocity.x = DirectionX * moveSpeed;
    _rigidbody.velocity = velocity;
}