Getting errors when i try to get game to restart when i hit an obstacle or fall of ground - visual-studio

Question

Please excuse me I'm a complete novice at all this but I'm trying to make a game following "Brackeys How To Make A Video Game" I'm on video 8 if that helps. I can't seem to find what i have done wrong i have added my scripts for "player movement", "player collision" and "game manager". Please if there is anything else you need to help me please ask i really don't want to give up just yet was really enjoying doing this.
Thank you all
using UnityEngine;
public class PlayerMovement : MonoBehaviour {
// This is a reference to the Rigidbody component called "rb"
public Rigidbody rb;
public float forwardForce = 2000f; // Variable that determines the forward force
public float sidewaysForce = 500f; // Variable that determines the sideways force
// We marked this as "Fixed"Update because we
// are using it to mess with physics.
void FixedUpdate ()
{
// Add a forward force
rb.AddForce(0, 0, forwardForce * Time.deltaTime);
if (Input.GetKey("d")) // If the player is pressing the "d" key
{
// Add a force to the right
rb.AddForce(sidewaysForce * Time.deltaTime, 0, 0, ForceMode.VelocityChange);
}
if (Input.GetKey("a")) // If the player is pressing the "a" key
{
// Add a force to the left
rb.AddForce(-sidewaysForce * Time.deltaTime, 0, 0, ForceMode.VelocityChange);
}
if (rb.position.y < -1f)
{
FindObjectOfType<GameManager>().EndGame();
}
}
}
using UnityEngine;
public class PlayerCollision : MonoBehaviour {
public PlayerMovement movement; // A reference to our PlayerMovement script
// This function runs when we hit another object.
// We get information about the collision and call it "collisionInfo".
void OnCollisionEnter (Collision collisionInfo)
{
// We check if the object we collided with has a tag called "Obstacle".
if (collisionInfo.collider.tag == "Obstacle")
{
movement.enabled = false; // Disable the players movement.
FindObjectOfType<GameManager>().EndGame();
}
}
}
using UnityEngine;
using UnityEngine.SceneManagement;
public class GameManager : MonoBehaviour {
bool gameHasEnded = false;
public float restartDelay = 1f;
public GameObject completeLevelUI;
public void CompleteLevel ()
{
completeLevelUI.SetActive(true);
}
public void EndGame ()
{
if (gameHasEnded == false)
{
gameHasEnded = true;
Debug.Log("GAME OVER");
Invoke("Restart", restartDelay);
}
}
void Restart ()
{
SceneManager.LoadScene(SceneManager.GetActiveScene().name);
}
}
when i fall off ground:
NullReferenceException: Object reference not set to an instance of an object
PlayerMovement.FixedUpdate () (at Assets/Scripts/PlayerMovement.cs:32)
when i hit an obstacle:
NullReferenceException: Object reference not set to an instance of an object
PlayerCollision.OnCollisionEnter (UnityEngine.Collision collisionInfo) (at Assets/Scripts/PlayerCollision.cs:15)

Answer 1

It seems to me that FindObjectOfType<GameManager>() is returning null, which is causing a null reference exception when you attempt to call the EndGame function. This most likely means that there is no object in your scene with the GameManager component on it. The solution to this problem is simple:
Create an empty object in your scene and add the GameManager component to it. This will fix the error in this instance, but it could happen in the future if you're not careful. It is also a good idea to check if you found an object or not before calling functions on it:
GameManager gm = FindObjectOfType<GameManager>();
if (gm != null)
{
gm.EndGame();
}