Returning button text with the onAction property

I have a method that takes in a list of names and then create buttons for each name on the list. I want to return the name in the form of a string or which number in the list was clicked, but I find it hard to do

public static String display(List<String> names) {
    Stage window = new Stage();
    window.setTitle("title");
    GridPane layout = new GridPane();

    for (int i = 0; i < names.size(); i++) {
        Button b = new Button(names.get(i);
        GridPane.setConstraints(b, 0, i);
        b.setOnAction(e - > {
            // return names.get(i);
            // or the number in the list
            // or the text of the button
        });

        layout.getChildren().add(b);
    }

    Scene scene = new Scene(layout, 300, 250);
    window.setScene(scene);
    window.showAndWait();

    return null;
}

What I tried:

    String s = "";
    b.setOnAction(e - > {
        s = b.getText();
    });
    
    return s;

But I get the following error: local variable is defined in an enclosing scope must be final or effective final.

Why not do

public static String display(List<String> names) {
StringBuilder result = new StringBuilder();
Stage window = new Stage();
window.setTitle("title");
GridPane layout = new GridPane();
for (int i = 0; i < names.size(); i++) {
String name = names.get(i);
Button b = new Button(name); GridPane.setConstraints(b, 0, i);
b.setOnAction(e -> {
result.append(name);
window.close();
});
layout.getChildren().add(b);
}
Scene scene = new Scene(layout, 300, 250);
window.setScene(scene);
window.showAndWait();
return result.toString();
}

If you use a VBox, which seems more natural, you can make the code cleaner (since you don't need the list index):

public static String display(List<String> names) {
StringBuilder result = new StringBuilder();
Stage window = new Stage();
window.setTitle("title");
VBox layout = new VBox();
for (String name : names) {
Button b = new Button(name); 
b.setOnAction(e -> {
result.append(name);
window.close();
});
layout.getChildren().add(b);
}
Scene scene = new Scene(layout, 300, 250);
window.setScene(scene);
window.showAndWait();
return result.toString();    
}

You basically have two options here.

Option 1:

System.out.println(b.getText());

Option 2: What I prefer

Button tempButton = ((Button)e.getSource());
System.out.println(tempButton.getText());

Full Code: I would recommend against doing this! I think you should use either Alert or Dialog to accomplish this!

import java.util.ArrayList;
import java.util.List;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
/**
* JavaFX App
*/
public class App extends Application {
@Override
public void start(Stage stage) {
List<String> names = new ArrayList();
names.add("john");
names.add("Kim");
Button button = new Button("List of Names Menu");
button.setOnAction((e) -> {
System.out.println(display(names));
});
StackPane layout = new StackPane();
layout.getChildren().add(button);
Scene scene = new Scene(layout, 300, 250);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch();
}
public String display(List <String> names) {
Label label = new Label();
Stage window = new Stage();
window.setTitle("title");
GridPane layout = new GridPane();
for (int i = 0; i < names.size(); i++) {
Button b = new Button(names.get(i));
GridPane.setConstraints(b, 0, i);
b.setOnAction((e) -> {
label.setText(b.getText());
window.close();
});
layout.getChildren().add(b);
}
Scene scene = new Scene(layout, 300, 250);
window.setScene(scene);
window.showAndWait();
return label.getText();
}
}