I've followed this tutorial (https://unity3d.com/pt/learn/tutorials/projects/roll-ball-tutorial/displaying-score-and-text) to make a Text updates every time my scripted score changes and it worked fine.
But i'd like to use TextMeshPro instead of the simple Text.
I've already made all the necessary changes in my code, such as:
using TMPro
public TextMeshProUGUI scoreText; (instead of public Text scoreText)
scoreText = gameObject.GetComponent(); (inside void Start())
scoreText.text = "Score: " + score.ToString(); (inside my function)
When in Play Mode I receive the "NullReferenceException: Object reference not set to an instance of an object" message.
I discovered the reason. When I enter Play Mode, I see in the Inspector that the TextMeshProUGUI that was assigned to the script is automatically unassigned.
I've made a stand alone script and added to a TextMeshProUGUI to check if my code was working with TextMeshPro, and it was.
The thing is: I don't want one separated script only to update the TextMeshPro. I need, as the tutorial above, the TextMeshPro being a public variable inside a big script with all other functions.
If, after I enter Play Mode, I assign the TextMeshProUGUI manually by dragging it to the Inspector, the Score works!
Why Texts, preFabs and everything stay assigned to my gameObject when I enter Play Mode, but the TextMeshProUGUI doesn't?
I think the code is ok, because it works if I assign the TextMeshProUGUI manually. But, anyways...
public class SnakeController : MonoBehaviour
{
public TextMeshProUGUI scoreText;
private int score;
void Start()
{
....
scoreText = gameObject.GetComponent<TextMeshProUGUI>();
score = 0;
setScoreText();
}
public void setScoreText()
{
scoreText.text = "Score: " + score.ToString();
}
}
The big issue is the TextMeshProUGUI be unassigned in the moment I enter Play Mode.
Your textmesh does not get "automatically unnasgined". You are explicitly telling it to assign something else, on this line:
scoreText = gameObject.GetComponent();
Your textmesh is probably not on the same object as the controller, as it needs to be child to a canvas to work. So that command is not finding what it's looking for, returning null, and thus assigning null. Use GetComponentInChildren<TextMeshProUGUI>() or FindObjectOfType<TextMeshProUGUI>() instead. Depending on if the textmesh is decendant of the controller object or on a different object entirely. And since you are assigning through script, don't worry about assigning in the inspector. In fact, make the field private so it doesn't even show up in the inspector.
Or assign in the inspector and remove the script assignment. Doing both is unnecessary, redundant and confusion- and error-prone. As you just found out.
Related
This question already has answers here:
How to access a variable from another script in another gameobject through GetComponent?
(3 answers)
Closed 25 days ago.
I am in no way a coding novice but I just picked up unity and I'm trying "get it"
My question involves this code. it is not part of an active project. it is simply an attempt to understand the system
private SpriteRenderer beans2;
public Sprite beanimmage;
// Start is called before the first frame update
void Start()
{
beans2 = gameObject.GetComponent<SpriteRenderer>();
beans2.sprite = beanimmage;
}
from what I understand this code allows me to manipulate the SpriteRenderer of the game object this code is attached to by assigning it to beans2 and then changing the Sprite of beans2 to beanimmage and works fine in the system
My question is -
Is their a way to assign beans2 to the spriterenderer of a diffident game object? The object i have this code attached to is just a game object called test is their a way to assign the beans2 variable to the SpriteRenderer of my test2 object instead ?
something like this ?
beans2 = test2.gameObject.GetComponent<SpriteRenderer>();
beans2 = gameObject.test2.GetComponent<SpriteRenderer>();
The GetComponent() Function is apart of every gameobject so to get components on other gameobjects you need to reference that gameobject in a variable, something like this:
public GameObject test2;
private SpriteRenderer test2Renderer;
public Sprite beanImage;
void Awake()
{
test2Renderer = test2.GetComponent<SpriteRenderer>();
test2Renderer.sprite = beanImage;
}
Alternatively, you can just get the component of the test2 object from the inspector because you are using public variables. To do this make a sprite renderer variable field and make it public so it is shown in the inspector, then drag the test2 object into the field and it will automatically get the sprite renderer component off that object.
Finally, you could also just do this with one field. This method would be used when you only want to access the GameObject and nothing else:
public GameObject test2;
public Sprite beansImage;
void Awake
{
test2.GetComponent<SpriteRenderer>().sprite = beansImage;
}
Any way works and you should do it the second way if you want to work with public variables and rely on the inspector but if you only need the gameobject then go with method 3. Method 1 is probably the best way to do it so you can change the sprite later if you want.
I have written a C# script in Unity to play a sequence of 360-degree videos of one-min duration each. The script works as expected, thanks to the support received on stackoverflow. I would now like to add a delimiter of a few seconds between each video playback, something like a blank screen which would help differentiate between the beginning and end of each video.
I tried using a GameObject with an Image on a Canvas and then setting it active after each video is played. However, it does not work as expected.
private GameObject gameobject;
gameobject = GameObject.FindGameObjectWithTag("Delimiter");
gameObject.SetActive(true);
Unfortunately, GameObject.FindWithTag(string tag) only returns active GameObjects. You cannot find an object that is disabled with this method. There are a few solutions:
Set the GameObject reference to public or add the [SerializeField] attribute, allowing you to configure it in the editor.
Start the GameObject as active and cache a reference to it before it becomes inactive. (in the awake method, or elsewhere)
Update edit for more clarification on #2:
All GameObjects run Awake() and Start() before they perform any other logic.
You could move your
private GameObject canvasObject;
to a class-level variable (instead of inside a method), and inside of the Awake() method, like this:
void Awake()
{
canvasObject = GameObject.FindWithTag("Delimiter");
}
Now you have a cached reference to your canvasObject, so you don't need to perform a GameObject.FindWithTag every time. Now you can have this method:
public void TurnOnImage()
{
canvasObject.SetActive(true);
}
My Problem:
I cant get it to work, that every Building has its own SpawnPoint.
I'm working on an RTS like build mechanism. I have set it up that after pressing a key I can place buildings in the scene. The buildings get instantiated from a prefab and after they get instantiated they get a script called "BuildingScript" attached to them. Now i want to implement, so that i get a individual spawn point for every building (for now just next to it). I got a UI set up with a button, which by pressing spawns a unit at the building.
I had the "BuildingScript" attached to the prefab, but when i set the spawn point for one Building, it set it for every Building in the Scene. So a Unit was Spawned always at the same Buidling.
I want to set it up, that every Building has its own spawn point. Thats why I want to give every Building the script "BuildingScript" when Instatiated, because I hope, that this way every script gets handled individually. Is that right? Or will it still set the same point for every building, because the script is still the same?
Also I wanna reference the current placed building to the button, so when its clicked, it will run only the code of the last placed building (for now). I think I cant do this by using "On Click()" Of the Button, because my clone isnt Instatiated yet, so I have to reference the clone to the button somehow via Script, so the button works with the clone.So my problem is, that I need to set a reference from my cloned Building to the Button, after I placed the clone.
I googled a lot on how to do this, but didnt found any answers to my problem besides this https://forum.unity.com/threads/controlling-instantiated-game-objects-from-ui-buttons.332005/.
But I cant get it to work and I think it will not work because my clone is an Object and not a GameObject, so I could never set reference to it to call the funktion SpawnUnit(), because GetComponent only works for a GameObject.
Now I'm really at a point where I just don't know how Unity handles these kind of things.
BuildingScript on the Instantiated Building
public class BuildingScript : MonoBehaviour
{
public bool SavePos = false;
public Vector3 SpawnPoint;
public Vector3 BuildingPos;
public GameObject Unit;
void Start()
{
FindObjectOfType<SpawnButtonReference>().GiveReference(this);
}
public void SpawnUnit()
{
//I did this because if a building gets instatiated i wanted it to save its
Position to Spawn Units from it (doesnt really work though).
"MousePos" ist the last Position of the Mouse in the PlacementScript, before klicking to place the building.
if (SavePos == false)
{
BuildingPos = GameObject.FindObjectOfType<GroundPlacementController>().GetComponent<GroundPlacementController>().MousePos;
Debug.Log(BuildingPos);
SavePos = true;
}
float PosX = BuildingPos.x + 2;
float PosZ = BuildingPos.z + 2;
SpawnPoint = new Vector3(PosX, 0, PosZ);
Debug.Log("Spawn" + SpawnPoint);
Instantiate(Unit, SpawnPoint, Quaternion.identity);
}
}
Script on the Button
public class SpawnButtonReference : MonoBehaviour
{
public GameObject objectReference = null;
internal void GiveReference(BuildingScript Object)
{
objectReference = Object;
}
void OnButtonPress()
{
if (objectReference != null)
{
objectReference.GetComponent<BuildingScript>().SpawnUnit();
}
}
}
So I solved it myself with a little workaround. Instead of trying to reference the clone, I wrote a script on the Spawn Button which searches all Objects with the "BildingScript" then if they are Selected (which can only be one Building) it spawns a Unit at its Spawn point.
The Building itself saves his spawn point when being placed (so when Input.GetMouseButtonUp(0))
works very well for me :)
I have the following piece of code. I referenced the text component in the editor to no_lives. The gamemanager (singleton) is being instantiated a scene before. The debug.log() shows 5 in the console. But when I try to set the text I get that the reference is not set to an instance of the object. Why is that?
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
public class level1_script : MonoBehaviour {
public Text no_lives;
// Use this for initialization
void Start () {
no_lives = GetComponent<Text>();
}
// Update is called once per frame
void Update () {
int lives_n = gamemanager.lives_f ();
Debug.Log (lives_n);
no_lives.text = lives_n + " x";
}
}
Are you certain that Start() was called before Update and that the GetComponent is actually setting a value to no_lives?
If not then code defensively. Also lives_n needs to be converted to a string lives_n.ToString() + " x" or use a format.
void Update () {
int lives_n = gamemanager.lives_f ();
Debug.Log (lives_n);
if(no_lives != null) {
no_lives.text = string.Format("{0} x", lives_n);
}
}
EDIT:
But when I try to set the text I get that the reference is not set to
an instance of the object.
That's because when you do GetComponent<Text>(), it will look for the instance of Text component on the-same GameObject your level1_script script is attached to.
You have two choices:
1.Attach Text component that GameObject your level1_script script is atached to then your current code should work.
2.If you already have the Text component attached to another GameObject, let's say an Object called "MyText", use GameObject.Find to find "MyText" then perform GetComponent on it to get the Text component.
no_lives = GameObject.Find("MyText").GetComponent<Text>()
Edit:
Well, both Text and script are attached to the same object
prntscr.com/f7p7vx
It's likely attached to multiple GameObject and the other GameObject does not have the Text script attached to it.
Select the level1_script script, go to Assets --> Find References in Scene then remove the duplicated script from other objects.
As the script logs '5' in the debug log, it seems to me that the variable lives_n is used correctly.
My guess is that the component "no_lives" isn't filled (that's what is often causing the "reference is not set to an instance of the object" error)
I suggest that you try to add the script to the UI Text object in your scene, this way the script finds the "Text" component on that object.
It's important to know the differences between objects and components, because they're both essential parts of unity. Objects are "things" in your scene, like cubes, cameras and stuff like that. Components on the other hand are part of object and define the properties of that object. For example: a camera object has a camera component to make it a camera and to make it actually viewable by the user.
The GetComponent<>() method searches for a (in your case) Text component on the object the script is attached to.
Hope this helps!
(oh and don't forget to remove the script from the other object you've placed it on, in case this works. Otherwise you'll still get errors)
how can I display 3D text after certain time then hide it after certain time
My tries
public Text text_tap;
GameObject.Find("3dtext").active = true; // first try but it dosnt work
if (Time.time > 5) {
// second try but it I cant attach my 3d text to my script
text_tap.gameObject.SetActive(true);
}
I cant find any thing in 3D documentation
I don't know the exactly problem, but there you have some hints:
If you search in the scene for a GameObject that is deactivated it won't find it. The Gameobject MUST be active for the GameObject.Find() function to work. The easiest thing you can do is to keep the GameObject activated, and if the initial state is for it to stay hidden just hide it in the Awake().
Secondly, seems that you are trying to access a TextMesh object
but you reference in your code a Text object.
If you find a GameObject and request a Component that the GO does not contains, it returns null.
Finally The api to Activate/Deactivate a GameObject (GO) is
myGameobject.SetActive(true)
The one you are using (myGameobject.active = true) is deprecated
Try this example, it should work:
public YourMonoBehaviour : MonoBehaviour
{
public TextMesh text_tap;
float awakeTime;
void Awake()
{
// Remember to activate the GO 3dtext in the scene!
text_tap = GameObject.Find("3dtext").GetComponent<TextMesh>():
awakeTime = Time.time
}
void Update()
{
if ((Time.time - awakeTime) > 5)
{
// second try but it I cant attach my 3d text to my script
text_tap.gameObject.SetActive(true);
}
}
}
If you need to "do something after a delay" you're talking about Coroutines.
Checking Time.time will only check if the game has been running for x time, and using Thread.Sleep in Unity will cause it to delay since you're causing an Update or similar to lock and not return.
Instead, use
yield return WaitForSeconds(5);
text_tap.gameObject.SetActive(false);
As another warning, this code assumes that the target object is not the same gameObject as the one hosting this script, since coroutines do not execute on inactive objects. Similarly, disabling an ancestor (via the scene hierarchy, or transofrm.parent) of a gameObject disables the gameObject itself.
If this is the case, get the component that renders 3d text and disable it instead of the whole gameObject via the enabled field.
you can also use Invoke() to achieve. as explained above note that the text would have to be set by other means than Find cause if it is not active it will not find it.
void Start() //or any event
{
Invoke("ShowTextTap", 5f);//invoke after 5 seconds
}
void ShowTextTap()
{
text_tap.gameObject.SetActive(true);
//then remove it
Invoke("DisableTextTap", 5f);
}
void DisableTextTap()
{
text_tap.gameObject.SetActive(false);
}