Button OnClick() UnityEvent

[glad drum]

Okay let's run through the checklist

1. There are no errors in the console, either before or after you enter play mode.

2. Your Button component is on a game object which is the child of an object with the Canvas component.

3. There is a game object with an Event System component on it in your scene.

4. Your script has the class declaration public class GachaStart : MonoBehavior {, and it's inside a file named "GachaStart.cs"

5. You've dragged that "GachaStart.cs" file from the Assets directory in your Project window to some game object in your scene.

6. You've dragged that game object which now has the GachaStart component attached to it to the "On Click()" object field in the Button's inspector.

7. You've selected "GachaStart > OnClick" from the "Function" drop down in the "On Click()" element on the Button component.

8. There's not some other UI element which extends in front of your button, and may be intercepting click events. If there is, then the button will not change visually when you click on it.

If all of the above is correct, it should be working 😅

[fathom dragon]

1. no error at all

3 there is no event component

and all the other are good x)

(sorry @glad drumi was asleep x) )

so i added the event system, now the button got clicked but i got a new error i didnt had before (wish means we are progressing xD)

" NullReferenceException: Object reference not set to an instance of an object" but if i understand it well, that means my reference to the button isnt correct, gotta check for typo

mhhh

as we can see in both screen, my button is well named...

ok so i fixed it, now the arrowimage appear, but the button stay there but it's supposed to disapear :/ xD

[naive pulsar]

what's the problem?

[fathom dragon]

the button is supposed to disapear when i click on the button, but it dont

[naive pulsar]

by disappear you mean "deleting it" or "making is inactive"?

[fathom dragon]

2nd

[naive pulsar]

how do you make it?

in code I mean

[fathom dragon]

using UnityEngine;
using UnityEngine.UI;

public class gachastart : MonoBehaviour
{
    public Image arrowImage;

    public void OnClick()
    {
        Debug.Log("Bouton GachaButton cliqué !");
        gameObject.SetActive(false);
        arrowImage.gameObject.SetActive(true);
    }
}

[naive pulsar]

do you call it?

[fathom dragon]

yep

[naive pulsar]

is "Bouton GachaButton cliqué !" written in console?

[fathom dragon]

yes

and the arrow appear as intended

[naive pulsar]

where does script "gachastart" hang?

we write scripts form capital btw

[fathom dragon]

there, and i didnt name it with the traditional form because it's in this thing

[naive pulsar]

is it button?

[fathom dragon]

no thats the object in wish i've putted the script in order to put it in the button

[naive pulsar]

yes, how to you pretend to disable the button if you disable gameObject that the script hangs on?

[fathom dragon]

i dont understand

[naive pulsar]

what exactly?

[fathom dragon]

my script is in the button

it would not work otherwise

[naive pulsar]

wait

I think we have problems with English🙄

show your gachastart gameObject @fathom dragon

and I would rather this process was a bit quicker

[naive pulsar]

gachastart is not the button

you make gachastart gameObject inactive

here: gameObject.SetActive(false);

[fathom dragon]

yes, theres the button, with the script in :

[naive pulsar]

yes, read my previous messages

stop, wait

why do you even have gachastart script on both button and "gachastart" gm

show me full inspector of that button

[naive pulsar]

show me full unity with this inspector too

[naive pulsar]

it must be set to inactive

are you sure it is not?

so the button is definitely clicked?

[fathom dragon]

yes

[fathom dragon]

yes

[naive pulsar]

try writing the name of the gameObject when clicking

[fathom dragon]

if it was inactive it would be as the arrowimage

[naive pulsar]

print(name + " was clicked");

you have several script references

[fathom dragon]

so how can i fix this ?

[naive pulsar]

sorry, I just needed to go for a while

[naive pulsar]

as I have expected

"gachastart" was clicked, not the button

do you understand now?

[fathom dragon]

yeah, but how do i fix it

[naive pulsar]

you need to make the button be clicked, not gachastart

[fathom dragon]

so i changed the script to be that

using UnityEngine;
using UnityEngine.UI;

public class gachastart : MonoBehaviour
{
    public Image arrowImage;
    private Button GachaStartButton;

    private void Start()
    {
        GachaStartButton = GetComponent<Button>();
    }

    public void OnClick()
    {
        Debug.Log("Bouton GachaButton cliqué !");
        GachaStartButton.gameObject.SetActive(false);
        arrowImage.gameObject.SetActive(true);

    }
}

but no i have the error

NullReferenceException: Object reference not set to an instance of an object

[naive pulsar]

this error appears here:

GachaStartButton = GetComponent<Button>();

you cannot access Button component if GO does not have it

[fathom dragon]

go ?

[naive pulsar]

GameObject

[fathom dragon]

how do i declare it ?

[naive pulsar]

sorry?

[fathom dragon]

how do i give it to GO

[naive pulsar]

give what? button?

you do not need to

you don't have button on "gachastart" GO and you are trying to access it

it should be quite logical what to do with it I guess ?

[fathom dragon]

then how do i create one

[naive pulsar]

maybe you could ask so that I can understand?

[fathom dragon]

🤦‍♀️

u told me i dont have my button in the GO, so i want to know how do i fix it, do i create a new button, do i create a new reference into the GO, what im i supposed to do?

[naive pulsar]

there is a huge amount of possibilities according to what you need:

1. delete the script from Game Objects that do not have Button component

2. add button components to all Game Objects that should have the script

3. check whether GO has Button component when accessing it

[fathom dragon]

how do i do step 3

@glad drum can u help me there ? i unfortunately struggle to understand what idbb say :/

[glad drum]

Do you want your "gachastart" script to live on the Game Object with the Button, or do you want it to live separately from the button, on the "gachastart" Game Object?

(or do you want the script to be able to do either, so you can use it in multiple ways/places?)

[fathom dragon]

well actually, if i dont put it on an empty object on the scene i cant put it in the button :/

[glad drum]

Sure you can! There's no reason it needs to be in both places :)

[fathom dragon]

i must have done it the wrong way then, cause when i try to take it from the assets folder and drop it in the script placeholder of the button, it just show an sign saying i cant x)

[naive pulsar]

I guess I have written everything nicely

[fathom dragon]

yeah but unfortunatly your probably not english, neither do i, so comunication is hard x)

[naive pulsar]

no, I think that's because of your c# 🙄 and I am not trying to hurt you, sorry if I did

hold on

[glad drum]

Ah that's a good thing. You wouldn't want to do that... If you drag the script from the Assets folder to the OnClick() inspector, then it wouldn't refer to a component in your scene... You would be trying to run code which is not in your scene, so it would not do anything.

[naive pulsar]

that's not step 3, that's 3rd possibility
you can check whether GachaStartButton is null when using it

anyway I do not think it's a good idea

you can also

[RequireComponent(typeof(UnityEngine.UI.Button))] // I hope correct type

public class gachastart : MonoBehaviour
{
    // ...
}

[glad drum]

But like IDBB was saying, this line:

        GachaStartButton = GetComponent<Button>();

It tries to get a reference to a Button component which is attached to the same game object which the script is attached to.

So when you put this script on an empty Game Object - your "gachastart" Game Object - that Game Object does not have a Button component on it. So GetComponent<Button>() returns null, and so GachaStartButton is null.

But you also have this script attached to the "GachaStartButton" Game Object. Because "GachaStartButton" does have a Button component attached to it, GetComponent<Button>() does return a reference to the button in that case:

[naive pulsar]

yes, that's evactly what I was trying to say

[naive pulsar]

but this line is enough I guess 🤔

[fathom dragon]

okay, im following, thats effectively what idbb was saying, so how can i fix this 🤔

[fathom dragon]

it was to syntethised, i didnt understand

[naive pulsar]

I have literally gave you 3 possibilities 💀💀

[glad drum]

So to make the script on the "GachaStartButton" Game Object work, you would drag the "GachaStartButton" Game Object into the OnClick() inspector - you want it to access the script component which is already on "GachaStartButton". If you did this, then you could delete the "gachastart" Game Object - there's no reason to have two copies of the script for this one button.

[naive pulsar]

you should first understand whether you really need to have gachastart script on gachastart GO

you could also consider redacting your script for multiple buttons if you need it

[fathom dragon]

sososo, in the onclick()

i should put the button

and not the script

[naive pulsar]

using System.Linq;
using UnityEngine;
using UnityEngine.UI;

public class gachastart : MonoBehaviour
{
    [SerializeField] private Button[] buttons;

    private void Start()
    {
        buttons.ToList().ForEach(button => 
        {
            button.onClick.AddListener(_ => 
            {
                // do smth
            });
        });
    }
}

[glad drum]

Put the "GachaStartButton" Game Object in the field, so you can access the gachastart script which is attached to it.

The naming of all these things does not make this conversation any easier 😁

[fathom dragon]

im really sorry x)

so i put the GachaStartButton, in the onclick() of the inspector, i still have the same error

do i have to remove the gachastart for it to work ?

[glad drum]

The error is from the script running on the "gachastart" Game Object, yes - because it is still trying to get the Button component attached to "gachastart," but "gachastart" still does not have a button. You can delete "gachastart," yes

[fathom dragon]

oh that worked

after 2 days

we finally made a button disapear

amazing

thank you so much mate XD

[glad drum]

The other way you could have done this - if you wanted to make it work with the "gachastart" GameObject instead - you would change your code so that you can manually set GachaStartButton instead of using GetComponent<Button>() - because in this case the script would not be on the Game Object which has the Button component.

using UnityEngine;
using UnityEngine.UI;

public class gachastart : MonoBehaviour
{
    public Image arrowImage;
    public Button GachaStartButton;

    public void OnClick()
    {
        Debug.Log("Bouton GachaButton cliqué !");
        GachaStartButton.gameObject.SetActive(false);
        arrowImage.gameObject.SetActive(true);
    }
}

In this case you would drag the "GachaStartButton" Game Object into the "Gacha Start Button" field in the "gachastart" Game Object's inspector, so public Button GachaStartButton would now refer to the Button component on the "GachaStartButton" Game Object. You would drag the "gachastart" Game Object in to the OnClick() inspector. And you would remove the gachastart script component from the "GachaStartButton" Game Object

[fathom dragon]

@naive pulsaryou to !

[fathom dragon]

i thaught about it ! and i tried it, but i think, now that im seeing it written well, that i didnt understand it would have been on gachastart so, seeing nothing appear in the GachaStartButton i thaught it didnt work xd

by curiosity, how many time did it make that ur using unity ?

[glad drum]

Like, how long have I been using Unity?

[fathom dragon]

yes ^^

[glad drum]

I started learning it... three months ago, I think?

I've been coding for many years, but I'm new to C# as well.

The Junior Programmer Pathway on Unity Learn was really helpful for figuring out the Unity basics 👍

[fathom dragon]

amazing! i hope i'll be that good in three month !

[glad drum]

Keep at it 😁

[naive pulsar]

I am sorry, I was just missing the full conversation because of some reasons

but I am glad you both have solved it

[fathom dragon]

oh dont worry! u were really helpfull ! thank a lot

[naive pulsar]

write here if something if another issue happens, I have notifications switched

[fathom dragon]

yo guys i have a new problem !

this is the code :

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class CardScrollAnimation : MonoBehaviour
{
    [SerializeField] private List<Color> rarityColors = new List<Color>();

    void Start()
    {
        for (int i = 0; i < 10; i++)
        {
            GameObject card = new GameObject("Card" + i);
            card.transform.SetParent(transform);

            RectTransform rectTransform = card.AddComponent<RectTransform>();
            rectTransform.sizeDelta = new Vector2(150, 200);

            Image image = card.AddComponent<Image>();
            image.color = rarityColors[Random.Range(0, rarityColors.Count)];

            Vector3 position = new Vector3(0, 70, 0);
            card.transform.localPosition = position;
        }
    }

    void Update()
    {
        float scrollSpeed = 100.0f;
        transform.Translate(Vector2.left * scrollSpeed * Time.deltaTime);
    }
}

basically, everything work, but the image dont appear :/

@glad drum can u try to help me ? ^^

[glad drum]

Does that throw any errors?

I think

RectTransform rectTransform = card.AddComponent<RectTransform>();

Might work a little strangely... I don't think a GameObject can have both a normal Transform and a RectTransform (the transform property either refers to the GO's Transform or it's RectTransform)... I'm not sure what Unity would do in that case. You might try creating the GameObject along with RectTransform to start with, just to rule that out as a problem.

        for (int i = 0; i < 10; i++)
        {
            GameObject card = new GameObject("Card" + i, typeof(RectTransform));
            card.transform.SetParent(transform);

            RectTransform rectTransform = card.transform as RectTransform;
            rectTransform.sizeDelta = new Vector2(150, 200);

            Image image = card.AddComponent<Image>();
            image.color = rarityColors[Random.Range(0, rarityColors.Count)];

            Vector3 position = new Vector3(0, 70, 0);
            card.transform.localPosition = position;
        }

[fathom dragon]

Nop x) in the end everything worked i solved it x)