Jumping in Unity. How to make a character jump once?

Question

2D

When you press the spacebar, the character jumps, but if you press the spacebar again during the flight, he will jump higher and so on until you press the spacebar. How to make a character jump once?

using UnityEngine;
using System.Collections;

public class Character : MonoBehaviour
{
    [SerializeField]
    private int lives = 5;
    [SerializeField]
    private float speed = 3.0F;
    [SerializeField]
    private float jumpForce = 15.0F;

    private bool isGrounded = false;

    new private Rigidbody2D rigidbody;
    private Animator animator;
    private SpriteRenderer sprite;

    private void Awake()
    {
        rigidbody = GetComponent<Rigidbody2D>();
        animator = GetComponent<Animator>();
        sprite = GetComponentInChildren<SpriteRenderer>();
    }

    private void FixedUpdate()
    {
        CheckGround();
    }

    private void Update()
    {
        if (Input.GetButton("Horizontal")) Run();    }

    private void Run()
    {
        Vector3 direction = transform.right * Input.GetAxis("Horizontal");

        transform.position = Vector3.MoveTowards(transform.position, transform.position + direction, speed * Time.deltaTime);

        sprite.flipX = direction.x < 0.0F;
    }

    private void Jump()
    {
        rigidbody.AddForce(transform.up * jumpForce, ForceMode2D.Impulse);
    }

    private void CheckGround()
    {
        Collider2D[] colliders = Physics2D.OverlapCircleAll(transform.position, 0.3F);

        isGrounded = colliders.Length > 1;
    }
}

Answer 1

Leave it as a killer feature

Answer 2

state pattern

Answer 3

Check that he is on the surface, then let him jump

Answer 4

https://habrahabr.ru/post/212309/
In this article you will find the answer to your question)

Answer 5

God, just check the velocity of the sprite's movement, if velocity.y != 0, then write return in the method for adding an impulse, otherwise add an impulse