How to permanently change variable via Button OnClick Listener - C#

Hi Guys,

I have a problem with dynamically created buttons. When I send variable trough AddListener it dose'nt change variable even If I use ref.

simple example:

void Start ()
{
createButton(variableIWantToChange);
}

void createButton(int variableGlobal)
{
GameObject goButton = (GameObject)Instantiate (prefabButton);
goButton.transform.SetParent (ParentPanel, false);
goButton.transform.localScale = new Vector3 (1, 1, 1);
Button tempButton = goButton.GetComponent<Button> ();
tempButton.GetComponentInChildren<Text> ().text = btnText;

tempButton.onClick.AddListener (() => ButtonClicked ( variableGlobal));
}
void ButtonClicked (int variableRef)
{
variableRef ++; // it will not change variableGlobal
}

Same with Ref:

void createButton(ref int variableGlobal)
{
GameObject goButton = (GameObject)Instantiate (prefabButton);
goButton.transform.SetParent (ParentPanel, false);
goButton.transform.localScale = new Vector3 (1, 1, 1);
Button tempButton = goButton.GetComponent<Button> ();
tempButton.GetComponentInChildren<Text> ().text = btnText;

int variableGlobal_2 = variableGlobal;
tempButton.onClick.AddListener (() => ButtonClicked ( variableGlobal_2));
}
void ButtonClicked (int variableRef)
{
variableRef ++; // it will not change variableGlobal
}

Any idea ? How to change global variable trough dynamically created buttons OnClick. I will appreciate any help with this.

Cheers,
Dominik

 

In order to make it compile, you had to copy the by-reference variable into a by-value variable. That by-value variable is then passed...um...by value...into ButtonClicked.

Make it so that createButton takes an Action<int>, then define a method on the class that hosts the variable you want to change and pass that method in to createButton.

 

ON CreateButton I want to pass different variables into the same ButtonClick listener method. The question is:
How to change global variable trough dynamically created buttons OnClick where I pass different variables for each button. I will appreciate any help

 

Just follow @MaxGuernseyIII's advice. Though I think an Action<int> is not needed, but either an UnityEngine.Events.UnityAction or System.Action. Using the latter you'd create an UnityAction internally anyway.

You'll then pass a lamda or any other matching method as either of both delegate types to the CreateButton method:

Code (csharp):

1. CreateButton(() => ++someVariable);
2. // or
3. CreateButton(() => someOtherVariable *= 2);

You could also use an integer-wrapping reference type to achieve your goal with your approach, but that's pretty much up to you.

 

It depends on where the value is coming from. If it is coming from the event, it needs to be an Action<int>. If it is intrinsic to the observer, then Action will suffice.