How to add Persistent Listener to Button.onClick event in Unity Editor Script
After spending so much time on this, I came to conclusion that this is a bug. This is a Mono bug.
Here are the references:
Unity wont fix this anytime soon. They usually don't fix stuff related to Mono since they are already working to upgrade to the latest Mono run-time.
Luckily, there are two other workarounds:
-
Use
AddObjectPersistentListener
andUnityAction
with generic parameter then pass in the generic to theDelegate.CreateDelegate
function.MyScript myScriptInstance = FindObjectOfType<MyScript>(); var go = new GameObject(); var btn = go.AddComponent<Button>(); var targetinfo = UnityEvent.GetValidMethodInfo(myScriptInstance, "OnButtonClick", new Type[] { typeof(GameObject) }); UnityAction<GameObject> action = Delegate.CreateDelegate(typeof(UnityAction<GameObject>), myScriptInstance, targetinfo, false) as UnityAction<GameObject>; UnityEventTools.AddObjectPersistentListener<GameObject>(btn.onClick, action, go);
-
Don't use
Delegate.CreateDelegate
at-all. Simply useAddObjectPersistentListener
.MyScript myScriptInstance = FindObjectOfType<MyScript>(); var go = new GameObject(); var btn = go.AddComponent<Button>(); UnityAction<GameObject> action = new UnityAction<GameObject>(myScriptInstance.OnButtonClick); UnityEventTools.AddObjectPersistentListener<GameObject>(btn.onClick, action, go);
Both of these gives you this:
The second solution does not require finding the function with reflection. You must bind the function before run-time. The first one uses reflection.
You probably need to use the first solution as it is very similar to what you are doing and you can provide the function name as a string variable.
Comments
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Umair M about 2 years
I am trying to do a simple thing:
- Create a new
GameObject
- Add a
Button
component to theGameObject
. - Add a persistent Listener to
Button
'sOnClick
event.
The method I am trying to register is in some other script. Here is piece of code that I am trying:
MyScript myScriptInstance = FindObjectOfType<MyScript>(); var go = new GameObject(); var btn = go.AddComponent<Button>(); var targetinfo = UnityEvent.GetValidMethodInfo(myScriptInstance, "OnButtonClick", new Type[]{typeof(GameObject)}); var action = (UnityAction) Delegate.CreateDelegate(typeof(UnityAction),go, targetinfo, false); UnityEventTools.AddPersistentListener(btn.onClick, action);
MyScript.cs looks like this:
public class MyScript : MonoBehaviour { public void OnButtonClick(GameObject sender) { // do some stuff here. } }
When I run this code, Buttons Onclick listener is empty like this:
If I change the line
var action = (UnityAction) Delegate.CreateDelegate(typeof(UnityAction), go, targetinfo, false);
to
var action = (UnityAction) Delegate.CreateDelegate(typeof(UnityAction), go, targetinfo, true);
I get :
ArgumentException: method argument length mismatch System.Delegate.CreateDelegate (System.Type type, System.Object firstArgument, System.Reflection.MethodInfo method, Boolean throwOnBindFailure)
I followed these instructions but don't know what went wrong here.
Any kind of help is truly appreciated.
- Create a new
-
Umair M over 7 yearsAs I am working on editor script, I preferred second method. Thanks anyway
-
Programmer over 7 yearsI don't think you understood the question. Take a look the image in his question then the image in my answer. OP is trying to register the Button and make it appear the Editor.
onClick.AddListener
cannot do that.