Unity3D Text not changing after being set in Start()

Question

I have a Canvas (World Space Render mode) with a Text and a Button component displayed in a tridimensional space (it's a VR app). The canvas instantiated at runtime using a prefab. I get a reference to the Text object using:

_codeTextLabel = canvasPrefab.transform.Find("CodeTextLabel").gameObject.GetComponent<Text>();

I want to update the text at run-time using:

void Update()
{
    _codeTextLabel.text = _codeText;
}

where _codeText is just a variable I update based on specific events. The problem is that the Text gets updated only the first time, but if I try to change the variable nothing happens. I have tried several combinations and also the method _codeTextLabel.SetAllDirty() but it doesn't work.

The only way to update the text is to re-instantiate the prefab.

Please include the entire class, so it is easier for us to debug. — Draco18s no longer trusts SE, Oct 28 '19 at 02:26

Arc2066 · Accepted Answer · 2019-10-28T00:58:08.983

Are you instantiating your prefab before setting the values. If you are storing the _codeTextLabel reference before instantiating then your reference will point to the prefab not the runtime object. I can't see the rest of your code, so I can't say for sure. (I would have asked as a comment, but as I'm new I don't have the reputation to do so)

edit: I did a test to try and recreate your problem. I made the following script and it appears to work as expected. CanvasPrefab is a worldspace canvas with a UnityEngine.UI.Text component attached. (The script is attached on an empty game object in the scene btw)

public class ChangeText : MonoBehaviour

    {
        public GameObject CanvasPrefab; 
        private GameObject runtimeCanvas;
        public string runtimeText = "something";
        private Text textRef;
        // Start is called before the first frame update
        void Start()
        {
            runtimeCanvas = GameObject.Instantiate(CanvasPrefab);
            textRef = runtimeCanvas.GetComponentInChildren<Text>();
        }

        // Update is called once per frame
        void Update()
        {
            textRef.text = runtimeText;
        }
    }

_codeTextLabel is correctly set (I have a check for it), it also work the first time. The problem is that it doesn't update after the first time. — Claus, Oct 28 '19 at 00:34
Would it be possible to share more of your code so I can get a better idea of what you're doing? — Arc2066, Oct 28 '19 at 00:47
basically I was getting a reference directly to the prefab instead of the instance generated at runtime. That's why the first change was reported (through instantiation) but all the following ones didn't have any effect. Thanks a lot! — Claus, Oct 28 '19 at 14:06

score 0 · Answer 2 · answered Oct 28 '19 at 04:27

as long as you did something wrong, It works absolutely so I guess there are several cases
1. Failed to do "_codeTextLabel = canvasPrefab.transform.Find("CodeTextLabel").gameObject.GetComponent();"
2. '_codeTextLabel' lost reference from 'GameObject.
3. Doesn't change runtimeText' change at all
4. Subscription of events failed I mean, your updating scripts doesn't get proper event to update that text.

Without codes, this is only thing I can guess for yours so please check above I hope there is case among above.

Unity3D Text not changing after being set in Start()

2 Answers2