Thursday, March 13, 2014

Implement event handler using Lambda Expression

The following code replace traditional EventHandler with Lambda Expression in GUI application, JavaFX:
package javafx8_hello;

import javafx.application.Application;
import javafx.event.ActionEvent;
//import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

/**
 *
 * @web http://java-buddy.blogspot.com/
 */
public class JavaFX8_Hello extends Application {
    
    @Override
    public void start(Stage primaryStage) {
        Button btn = new Button();
        btn.setText("Say 'Hello World'");
        
        /* Normal 
        btn.setOnAction(new EventHandler<ActionEvent>() {
            
            @Override
            public void handle(ActionEvent event) {
                System.out.println("Hello World!");
            }
        });
        */
        
        /*
        In Lambda Expression
        */
        btn.setOnAction((ActionEvent event) -> {
            System.out.println("Hello World!");
        });
        
        StackPane root = new StackPane();
        root.getChildren().add(btn);
        
        Scene scene = new Scene(root, 300, 250);
        
        primaryStage.setTitle("Hello World!");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
    
}

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