Question

A JavaFX UI class has a button named 'btnOk' that needs to call a void method with no parameters named 'displayResults' when it is clicked. Write the complete lambda-expression statement to set up the btnOk event handler to do this.

Answer 1

Please find the code below::

ButtonHandleUsingLambda.java

package gui;

import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;

public class ButtonHandleUsingLambda extends Application {
   public static void main(String[] args) {
       launch(args);
   }
   @Override
   public void start(Stage stage) {
       Scene scene = new Scene(new Group(), 450, 250);
       Button button = new Button("btnOk");
       GridPane grid = new GridPane();
       grid.setVgap(4);
       grid.setHgap(10);
       grid.add(button, 0, 2);
      
       button.setOnAction((event) -> {
           displayResults();
       });

       Group root = (Group) scene.getRoot();
       root.getChildren().add(grid);
       stage.setScene(scene);
       stage.show();
   }
  
   public static void displayResults() {
       System.out.println("Called me ?");
   }
}