Hello World, JavaFX Style

The best way to teach you what it is like to create and build a JavaFX application is with a “Hello World” application. An added benefit of this tutorial is that enables you to test that your JavaFX technology is properly installed.

The tool used in this tutorial is NetBeans IDE 7.1. Before you begin, ensure that the version of NetBeans IDE that you are using supports JavaFX 2. See the System Requirements for details.

Construct the Application

1. From the File menu, choose New Project.
2. In the JavaFX application category, choose JavaFX Application. Click Next.
3. Name the project HelloWorld and click Finish.
   NetBeans opens the HelloWorld.java file and populates it with the code for a basic Hello World application, as shown in Example 1-1.
   Example 1-1 Hello World

   package helloworld;
    
   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;
    
   public class HelloWorld extends Application {
       public static void main(String[] args) {
           launch(args);
       }
       
       @Override
       public void start(Stage primaryStage) {
           primaryStage.setTitle("Hello World!");
           Button btn = new Button();
           btn.setText("Say 'Hello World'");
           btn.setOnAction(new EventHandler() {
    
               @Override
               public void handle(ActionEvent event) {
                   System.out.println("Hello World!");
               }
           });
           
           StackPane root = new StackPane();
           root.getChildren().add(btn);
           primaryStage.setScene(new Scene(root, 300, 250));
           primaryStage.show();
       }
   }
   

Here are the important things to know about the basic structure of a JavaFX application:

• A JavaFX application defines the user interface container by means of a stage and a scene. The JavaFX Stage class is the top-level JavaFX container. The JavaFX Scene class is the container for all content. Example 1-1 creates the stage and scene and makes the scene visible in a given pixel size.
• In JavaFX, the content of the scene is represented as a hierarchical scene graph of nodes. In this example, the root node is a StackPane object, which is a resizable layout node. This means that the root node's size tracks the scene's size and changes when the stage is resized by a user.
• The root node contains one child node, a button control with text, plus an event handler to print a message when the button is pressed.

Figure 1-1 shows the scene graph for the Hello World application.

Figure 1-1 Hello World Scene Graph

Description of "Figure 1-1 Hello World Scene Graph"

Run the Application

Run the application, click the Say Hello World button, and verify that the text "Hello World!" is printed to the NetBeans output window. Figure 1-2 shows the Hello World application, JavaFX style.

Figure 1-2 Hello World, JavaFX style

Description of "Figure 1-2 Hello World, JavaFX style"

Where to Go Next

This concludes the basic Hello World tutorial, but continue reading for more lessons on developing JavaFX applications:

• Creating a Form in JavaFX teaches the basics of screen layout, how to add controls to a layout, and how to create input events.
• Fancy Forms with JavaFX CSS provides simple style tricks for enhancing your application, including adding a background image and styling buttons and text.
• Using FXML to Create a User Interface shows an alternate method for creating the login user interface. FXML is an XML-based language that provides the structure for building a user interface separate from the application logic of your code.
• Animation and Visual Effects in JavaFX shows how to bring an application to life by adding timeline animation and blend effects.
• Deploying Your First JavaFX Application describes ho w to run your application outside NetBeans IDE.