NullReferenceException in UI TextElement

Questions & Answers
1

So I’ve been following this basic tutorial about Unity when I ran into issues with trying to run a create a score variable that displays in the UI.

using UnityEngine.UIElements;
using UnityEngine;

public class Score : MonoBehaviour
{
   public Transform player;
   public TextElement score;

    void Update()
    {
     
        score.text = player.position.z.ToString("0");
    }
}

This is the error I got:
NullReferenceException: Object reference not set to an instance of an object
Score.Update () (at Assets/Scripts/Score.cs:12)

Also I cannot put an object in the inspector even though I declared TextElement as public.

2

UiDocumentController.cs

using UnityEngine;
using UnityEngine.UIElements;
public class UiDocumentController : MonoBehaviour
{
	[SerializeField] UIDocument _uiDocument = null;
	Label _timer;
	void OnEnable ()
	{
		OnBind( _uiDocument.rootVisualElement );
	}
	void Update ()
	{
		_timer.text = $"Time.time: {Time.time:0.00}";
	}
	void OnBind ( VisualElement root )
	{
		_timer = root.Q<Label>("timer");
	}
}

  • Add UIDocument component, make sure it’s Source Asset field is filled with an UXML file you built

  • Add UiDocumentController component (src above) and fill it’s UiDocument field

  • Edit UiDocumentController so it does what you need and that Q<Label>( ELEMENT NAME ) exist in the uxml file