OnCollisionEnter2D and OnCollisionExit2D not working properly

Questions & Answers
1

On the game, when you click the up arrow, the gravity is inverted. So when you click the down arrow, the gravity is set back to normal.

I don’t want the player to be able to flip up and down unless it is touching the ground. Below is what I have for the player movement. Currently, none of the debug logs are showing, and when I click the up arrow isTouching = true, when it should equal false.

I do have my ground objects tagged as Ground.

{

public float speed;
public Rigidbody2D rb;
public bool isTouching;

void Start()
{
    Rigidbody2D rb = GetComponent<Rigidbody2D>();
    isTouching = true;
}

void FixedUpdate()
{
    float moveHorizontal = Input.GetAxis("Horizontal");
    Vector2 movement = new Vector2(moveHorizontal, 0.0f);
    rb.velocity = movement * speed;

    if (Input.GetKeyDown(KeyCode.UpArrow) && (isTouching = true) ){
        rb.gravityScale = -25;
    }

    if (Input.GetKeyDown(KeyCode.DownArrow) && (isTouching = true))
    {
        rb.gravityScale = 25;
    }
}

void OnCollisionEnter2D(Collider2D collider)
{
    Debug.Log("entered");
    if (collider.gameObject.tag == "Ground")
        isTouching = true;
}

void OnCollisionExit2D(Collider2D collider) {
    Debug.Log("exited");
    if (collider.gameObject.tag == "Ground")
        isTouching = false;
}

}

2

@sylviafinger

OnCollisionEnter2D () and OnCollisionExit2D () both require a datatype of Collision2D to be passed in, not Collider2D

Change your methods to the following:

void OnCollisionEnter2D(Collision2D collider)
 {
     Debug.Log("entered");
     if (collider.gameObject.tag == "Ground")
         isTouching = true;
 }
 void OnCollisionExit2D(Collision2D collider) {
     Debug.Log("exited");
     if (collider.gameObject.tag == "Ground")
         isTouching = false;
 }

Next time, try to consult the Unity API when you’re having problems with collisions as it’s normally the first place many people have errors.

OnCollisionEnter2D - Unity Scripting API

Hope it helps.