Unity Jumps at Different Heights

Question

I'm making a 2D platforming game for mobile devices. I have a guiTexture, that when pressed, makes my sprite jump. But whenever I press the guiTexture, the sprite jumps at different heights every time, depending if I hold the button down, or lightly press it.

Here is the jump script I'm using:

    using UnityEngine;
using System.Collections;

public class Jump : MonoBehaviour {

    public GUITexture jumpButton;

    bool grounded = false;
    public Transform groundCheck;
    float groundRadius = 0.2f;
    public LayerMask whatIsGround;

    public float jumpForce = 700f;

    public GameObject character;

    void Start () {

    }

    void Update () {

    }

    void FixedUpdate () {
        grounded = Physics2D.OverlapCircle (groundCheck.position, groundRadius, whatIsGround);

        if (grounded && jumpButton.HitTest(Input.GetTouch(0).position)) {
            rigidbody2D.AddForce(new Vector2(0, jumpForce));
        }
    }
}

Answer 1

make your if statement check for the touchphase if the touch is down, then it will only fire once when you touch down

if (grounded && jumpButton.HitTest(Input.GetTouch(0).position) && Input.GetTouch(0).phase == TouchPhase.Began) {
        rigidbody2D.AddForce(new Vector2(0, jumpForce));
    }