Unity Toggle - Changing isOn through script does not trigger onvaluechanged

Unity Engine
1

So when i try to change the toggle’s is on through script… on value changed is not triggered. Why?

My toggles are part of a toggle group. Even Togglegroup.NotifyToggleOn does not do anything.
Please need help.

Thanks

1 Like
2

Toggles do trigger OnValue Changed when you set their toggle direclty through script.

You can test it by Creating a new Scene. Add a UI Button, UI Toggle and an Empty Game Object:
Put this script on the Empty Game Object:

using UnityEngine;
using UnityEngine.UI;
using System.Text.RegularExpressions;

public class GenericTest : MonoBehaviour
{
   public Toggle myToggle;
   public void ValueChanged()
    {
        Debug.Log("Value Changed");
    }

    public void ChangeToggle()
    {
        myToggle.isOn = !myToggle.isOn;
    }

}

Hook the Toggles On Value Changed to GameObject’s Value Changed Method
Hook the Buttons On Click to the GameObject’s Change Toggle Method
And make sure to drag the Toggle to the GameObject’s Public myToggle in the editor.

Then click the button you will see the Toggle turn on and off and you will get Debug Messages.

What I expect is happening is whenever a Toggle is “On” and you set Toggle.isOn = true; this will NOT trigger an OnValue Changed… because you didn’t actually change the toggles value. (obviously the same thing occurs if its off and you toggle it off). If you code is depending on that OnValueChange to do certain things when a toggle is turned on, but its already turned on… then thats where your error is.

2 Likes
3

Apparently it does not trigger in mine. I do change it similarly as you have done. But it never triggers on value changed.
Weird! Using unity 5.3.6 p4

Or maybe Im using dynamic toggle changed function suggested by Unity. Maybe there is an issue with that. Ill check with a normal function and get back

4

Also make sure your actaully changing the toggle. If its on and you set it to “on” it won’t trigger an OnValueChanged.

5

I thought I was having the same issue of OnValueChanged not getting called when updating isOn, but it was a Script Execution Order issue for me.

2 Likes
6

i think it is ugui not friendly.
look below:
public void NotifyToggleOn(Toggle toggle)
{
ValidateToggleIsInGroup(toggle);
// disable all toggles in the group
for (var i = 0; i < m_Toggles.Count; i++)
{
if (m_Toggles == toggle)
continue;
m_Toggles*.isOn = false;
_}_
_}*_
so we should set targettoggle.isOn = true at first,
then togglegroup.NotifyToggleOn(targettoggle)

3 Likes
7

Thanks, that helped!

8

isOn set to true is not worked.
I change state toggle button from script by this “Select” method.

toggle.Select();

3 Likes
9

On my test, I found the solution for this issue.

Toggle_Currency.toggle.isOn = false;
Toggle_Currency.toggle.isOn = true;

In my situation, I want to set toggle.isOn = true to trigger onValueChange Method, but it doesn’t work. So set toggle.isOn = false before it. This code can prepare a environment for toggle.isOn=true. In a word, If you want to trigger value changed, you must make the toggle change it’s value.

1 Like
10 
private void changeToggleState(bool state) {
            if (state) toggle.isOn = state;
            else toggle.onValueChanged?.Invoke(state);
        }

You can use this method

2 Likes
11

INCREDIBLY BIZARRE BUG IN 2020

If you happen to have an inactive Toggle in the scene, everything goes wrong.

2 Likes
12

@Fattie did you solve this issue?

13

@thiagolrosa unfortunately it’s just a bad unity bug. you have to just manually turn them all on/off/etc when things change. there’s no real solution as it’s a bad unity bug :confused:

1 Like
14

toggle.isOn = true; absolutely triggers its OnValueChanged event for my project. It’s quite frustrating. I’m not sure if it has something to do with the bug mentioned by @Fattie , but when my Server tells my clients to untoggle their toggles, the toggles toggle their toggle methods. :face_with_spiral_eyes:

15

Use
Toggle.SetIsOnWithoutNotify()

4 Likes
16

The exact answer is on the page below. As you can see Unity didn’t think as we programmers (used to use Visual Studio like environments). they want us to hook the process and listen to it. (and I don’t know why? :slight_smile: )

17

This doesn’t help my case - I got no problem with the user changing the toggle value. My issue is that I can’t initialise the toggle value based on a variable. Nothing, including SetIsOnWithoutNotify() makes any difference.

I want the toggle to be ticked or not, depending on whether a particular player setting is enabled. But setting the value in script does not alter the visual appearance of the toggle.

Hmm, okay there seems to be some bug in Unity (2021.3.8f1). I have two toggles, identical setup - one of them is getting the changes from script, the other not responding. Both have the same enabled / disabled status when the script attempts to set them, both are set at the exact same time.

18

Did you ever get this working? I’m having the exact same issue in 2021.3.10f. My toggles visibly turn off and on on all of my UI except one. No matter what I’ve tried, the toggle just does not allow for interaction. The value changes but the UI does not update whatsoever.

19

I’m having the same problem in 2021.1.28f1. I have 24 toggles in my group and one of them is always working but the others not working if I that one is triggered.

20

This is what worked for me:

toggle.isOn = true;
toggle.group.EnsureValidState();