Java Programming

Lecture 41: JavaFX Basics and GUI Programming

GTU Diploma in Computer Engineering

layout: two-cols

Learning Objectives

After this lecture, you will be able to:

Understand JavaFX architecture and components
Create basic JavaFX applications
Work with scenes, stages, and nodes
Handle user events and interactions
Use common JavaFX controls and layouts
Style applications with CSS
Build responsive user interfaces
Create data-driven applications with TableView

::right::

Lecture Overview

Introduction to JavaFX
JavaFX Application Structure
Scene Graph and Nodes
Common Controls
Layout Managers
Event Handling
CSS Styling
TableView and Data Binding
FXML and Scene Builder
Hands-on Exercises

What is JavaFX?

JavaFX is a modern UI toolkit for building rich desktop applications in Java.

Key Features

Rich UI Controls: Extensive set of built-in controls
CSS Styling: Web-like styling capabilities
FXML: XML-based markup for UI design
Scene Graph: Hierarchical representation of UI components
Hardware Acceleration: GPU-accelerated graphics
Media Support: Audio and video playback
Web Integration: WebView component for HTML content

JavaFX vs Swing

// Swing approach
import javax.swing.*;
import java.awt.*;

public class SwingExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Swing Example");
        JButton button = new JButton("Click me");
        button.addActionListener(e -> 
            JOptionPane.showMessageDialog(frame, "Button clicked!"));
        
        frame.add(button);
        frame.setSize(300, 200);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

// JavaFX approach
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class JavaFXExample extends Application {
    @Override
    public void start(Stage primaryStage) {
        Button button = new Button("Click me");
        button.setOnAction(e -> {
            Alert alert = new Alert(Alert.AlertType.INFORMATION, "Button clicked!");
            alert.showAndWait();
        });
        
        VBox root = new VBox(button);
        Scene scene = new Scene(root, 300, 200);
        
        primaryStage.setTitle("JavaFX Example");
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    
    public static void main(String[] args) {
        launch(args);
    }
}

JavaFX Application Structure

Every JavaFX application follows a specific structure.

Basic Application Template

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class BasicJavaFXApp extends Application {
    
    @Override
    public void start(Stage primaryStage) throws Exception {
        // Create the root node
        StackPane root = new StackPane();
        
        // Add components to the root
        Label label = new Label("Hello, JavaFX!");
        root.getChildren().add(label);
        
        // Create the scene
        Scene scene = new Scene(root, 400, 300);
        
        // Set up the primary stage
        primaryStage.setTitle("My JavaFX Application");
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    
    @Override
    public void init() throws Exception {
        // Called before start() - initialize application
        System.out.println("Application initializing...");
    }
    
    @Override
    public void stop() throws Exception {
        // Called when application is closing - cleanup resources
        System.out.println("Application stopping...");
    }
    
    public static void main(String[] args) {
        launch(args); // Launches the JavaFX application
    }
}

Application Lifecycle

import javafx.application.Application;
import javafx.application.Platform;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class LifecycleDemo extends Application {
    
    private TextArea logArea;
    
    @Override
    public void init() throws Exception {
        log("init() called - Application thread: " + Thread.currentThread().getName());
        // Initialize non-UI components here
        // This runs on the launcher thread, NOT the JavaFX Application Thread
    }
    
    @Override
    public void start(Stage primaryStage) throws Exception {
        log("start() called - JavaFX Application Thread: " + Thread.currentThread().getName());
        
        logArea = new TextArea();
        logArea.setEditable(false);
        logArea.setPrefRowCount(10);
        
        Button exitButton = new Button("Exit Application");
        exitButton.setOnAction(e -> {
            log("Exit button clicked");
            Platform.exit(); // Proper way to exit JavaFX application
        });
        
        VBox root = new VBox(10);
        root.getChildren().addAll(
            new Label("Application Lifecycle Demo"),
            logArea,
            exitButton
        );
        
        Scene scene = new Scene(root, 500, 400);
        primaryStage.setTitle("JavaFX Lifecycle");
        primaryStage.setScene(scene);
        primaryStage.show();
        
        log("Application started successfully");
    }
    
    @Override
    public void stop() throws Exception {
        log("stop() called - Application is shutting down");
        // Cleanup resources here
        // Save application state, close connections, etc.
    }
    
    private void log(String message) {
        String logMessage = System.currentTimeMillis() + ": " + message;
        System.out.println(logMessage);
        
        if (logArea != null) {
            Platform.runLater(() -> {
                logArea.appendText(logMessage + "\n");
            });
        }
    }
    
    public static void main(String[] args) {
        System.out.println("main() called - Main thread: " + Thread.currentThread().getName());
        launch(args);
        System.out.println("main() finished - Application has terminated");
    }
}

Scene Graph and Nodes

JavaFX uses a scene graph - a hierarchical tree of nodes.

Understanding the Hierarchy

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;

public class SceneGraphDemo extends Application {
    
    @Override
    public void start(Stage primaryStage) {
        // Stage (Window)
        //   └── Scene
        //       └── Root Node (Parent)
        //           ├── Child Node 1
        //           ├── Child Node 2
        //           └── Child Node 3 (Parent)
        //               ├── Grandchild 1
        //               └── Grandchild 2
        
        // Create leaf nodes (no children)
        Button button1 = new Button("Button 1");
        Button button2 = new Button("Button 2");
        Label label = new Label("This is a label");
        TextField textField = new TextField("Enter text here");
        
        // Create parent nodes that contain other nodes
        HBox buttonBox = new HBox(10); // Horizontal layout with 10px spacing
        buttonBox.getChildren().addAll(button1, button2);
        
        VBox inputBox = new VBox(5); // Vertical layout with 5px spacing
        inputBox.getChildren().addAll(label, textField);
        
        // Create root node
        VBox root = new VBox(20); // Main container
        root.getChildren().addAll(
            new Label("Scene Graph Hierarchy Demo"),
            buttonBox,
            inputBox,
            createInfoButton()
        );
        
        // Set some styling
        root.setStyle("-fx-padding: 20; -fx-alignment: center;");
        buttonBox.setStyle("-fx-alignment: center;");
        inputBox.setStyle("-fx-alignment: center;");
        
        Scene scene = new Scene(root, 400, 300);
        primaryStage.setTitle("Scene Graph Demo");
        primaryStage.setScene(scene);
        primaryStage.show();
        
        // Demonstrate node traversal
        demonstrateNodeTraversal(root);
    }
    
    private Button createInfoButton() {
        Button infoButton = new Button("Show Scene Graph Info");
        infoButton.setOnAction(e -> {
            Alert alert = new Alert(Alert.AlertType.INFORMATION);
            alert.setTitle("Scene Graph Information");
            alert.setHeaderText("Current Scene Graph Structure");
            alert.setContentText(
                "Stage\n" +
                "└── Scene\n" +
                "    └── VBox (root)\n" +
                "        ├── Label\n" +
                "        ├── HBox\n" +
                "        │   ├── Button 1\n" +
                "        │   └── Button 2\n" +
                "        ├── VBox\n" +
                "        │   ├── Label\n" +
                "        │   └── TextField\n" +
                "        └── Button (Info)"
            );
            alert.showAndWait();
        });
        return infoButton;
    }
    
    private void demonstrateNodeTraversal(VBox root) {
        System.out.println("Traversing scene graph:");
        traverseNode(root, 0);
    }
    
    private void traverseNode(Object node, int depth) {
        String indent = "  ".repeat(depth);
        System.out.println(indent + node.getClass().getSimpleName());
        
        if (node instanceof Parent) {
            Parent parent = (Parent) node;
            for (Object child : parent.getChildrenUnmodifiable()) {
                traverseNode(child, depth + 1);
            }
        }
    }
    
    public static void main(String[] args) {
        launch(args);
    }
}

Common JavaFX Controls

JavaFX provides a rich set of built-in controls.

Basic Controls

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class BasicControlsDemo extends Application {
    
    @Override
    public void start(Stage primaryStage) {
        VBox root = new VBox(10);
        root.setStyle("-fx-padding: 20;");
        
        // Label
        Label titleLabel = new Label("JavaFX Controls Demo");
        titleLabel.setStyle("-fx-font-size: 18px; -fx-font-weight: bold;");
        
        // Button
        Button actionButton = new Button("Click Me!");
        actionButton.setOnAction(e -> showAlert("Button clicked!"));
        
        // TextField
        TextField textField = new TextField();
        textField.setPromptText("Enter your name");
        
        // TextArea
        TextArea textArea = new TextArea();
        textArea.setPromptText("Enter multiple lines of text here...");
        textArea.setPrefRowCount(3);
        
        // CheckBox
        CheckBox checkBox1 = new CheckBox("Option 1");
        CheckBox checkBox2 = new CheckBox("Option 2");
        checkBox2.setSelected(true); // Pre-selected
        
        // RadioButtons (grouped)
        ToggleGroup radioGroup = new ToggleGroup();
        RadioButton radio1 = new RadioButton("Choice A");
        RadioButton radio2 = new RadioButton("Choice B");
        RadioButton radio3 = new RadioButton("Choice C");
        radio1.setToggleGroup(radioGroup);
        radio2.setToggleGroup(radioGroup);
        radio3.setToggleGroup(radioGroup);
        radio2.setSelected(true); // Pre-selected
        
        // ComboBox (Dropdown)
        ComboBox<String> comboBox = new ComboBox<>();
        comboBox.getItems().addAll("Java", "Python", "JavaScript", "C++", "Ruby");
        comboBox.setPromptText("Select a language");
        
        // ListView
        ListView<String> listView = new ListView<>();
        listView.getItems().addAll("Item 1", "Item 2", "Item 3", "Item 4", "Item 5");
        listView.setPrefHeight(100);
        
        // Slider
        Slider slider = new Slider(0, 100, 50);
        slider.setShowTickLabels(true);
        slider.setShowTickMarks(true);
        slider.setMajorTickUnit(25);
        
        Label sliderLabel = new Label("Value: 50");
        slider.valueProperty().addListener((obs, oldVal, newVal) -> 
            sliderLabel.setText("Value: " + Math.round(newVal.doubleValue())));
        
        // ProgressBar
        ProgressBar progressBar = new ProgressBar(0.6);
        
        // ProgressIndicator
        ProgressIndicator progressIndicator = new ProgressIndicator(0.75);
        
        // Button to demonstrate interactions
        Button demoButton = new Button("Show Current Values");
        demoButton.setOnAction(e -> showCurrentValues(textField, textArea, checkBox1, checkBox2, 
                                                     radioGroup, comboBox, listView, slider));
        
        // Add all controls to the root
        root.getChildren().addAll(
            titleLabel,
            new Separator(),
            new Label("Text Input:"),
            textField,
            textArea,
            new Separator(),
            new Label("Selection Controls:"),
            checkBox1,
            checkBox2,
            new Label("Radio Buttons:"),
            radio1, radio2, radio3,
            new Label("Dropdown:"),
            comboBox,
            new Label("List:"),
            listView,
            new Separator(),
            new Label("Value Controls:"),
            new Label("Slider:"),
            slider,
            sliderLabel,
            new Label("Progress Controls:"),
            progressBar,
            progressIndicator,
            new Separator(),
            actionButton,
            demoButton
        );
        
        Scene scene = new Scene(new ScrollPane(root), 400, 600);
        primaryStage.setTitle("JavaFX Controls Demo");
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    
    private void showAlert(String message) {
        Alert alert = new Alert(Alert.AlertType.INFORMATION);
        alert.setTitle("Information");
        alert.setHeaderText(null);
        alert.setContentText(message);
        alert.showAndWait();
    }
    
    private void showCurrentValues(TextField textField, TextArea textArea, 
                                 CheckBox checkBox1, CheckBox checkBox2,
                                 ToggleGroup radioGroup, ComboBox<String> comboBox,
                                 ListView<String> listView, Slider slider) {
        StringBuilder sb = new StringBuilder();
        sb.append("Current Values:\n\n");
        
        sb.append("TextField: ").append(textField.getText()).append("\n");
        sb.append("TextArea: ").append(textArea.getText().replaceAll("\n", " ")).append("\n\n");
        
        sb.append("CheckBox 1: ").append(checkBox1.isSelected()).append("\n");
        sb.append("CheckBox 2: ").append(checkBox2.isSelected()).append("\n\n");
        
        RadioButton selectedRadio = (RadioButton) radioGroup.getSelectedToggle();
        sb.append("Selected Radio: ").append(selectedRadio != null ? selectedRadio.getText() : "None").append("\n\n");
        
        sb.append("ComboBox: ").append(comboBox.getValue()).append("\n");
        sb.append("ListView Selection: ").append(listView.getSelectionModel().getSelectedItem()).append("\n\n");
        
        sb.append("Slider: ").append(Math.round(slider.getValue())).append("\n");
        
        Alert alert = new Alert(Alert.AlertType.INFORMATION);
        alert.setTitle("Current Values");
        alert.setHeaderText("Form Data");
        alert.setContentText(sb.toString());
        alert.showAndWait();
    }
    
    public static void main(String[] args) {
        launch(args);
    }
}

Layout Managers

Layout managers control how components are arranged in containers.

Common Layout Managers

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;

public class LayoutDemo extends Application {
    
    @Override
    public void start(Stage primaryStage) {
        TabPane tabPane = new TabPane();
        
        // VBox Layout
        Tab vboxTab = new Tab("VBox");
        vboxTab.setContent(createVBoxDemo());
        
        // HBox Layout
        Tab hboxTab = new Tab("HBox");
        hboxTab.setContent(createHBoxDemo());
        
        // BorderPane Layout
        Tab borderPaneTab = new Tab("BorderPane");
        borderPaneTab.setContent(createBorderPaneDemo());
        
        // GridPane Layout
        Tab gridPaneTab = new Tab("GridPane");
        gridPaneTab.setContent(createGridPaneDemo());
        
        // StackPane Layout
        Tab stackPaneTab = new Tab("StackPane");
        stackPaneTab.setContent(createStackPaneDemo());
        
        // FlowPane Layout
        Tab flowPaneTab = new Tab("FlowPane");
        flowPaneTab.setContent(createFlowPaneDemo());
        
        tabPane.getTabs().addAll(vboxTab, hboxTab, borderPaneTab, 
                                gridPaneTab, stackPaneTab, flowPaneTab);
        
        Scene scene = new Scene(tabPane, 600, 500);
        primaryStage.setTitle("JavaFX Layout Managers");
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    
    private VBox createVBoxDemo() {
        VBox vbox = new VBox(10);
        vbox.setPadding(new Insets(20));
        vbox.setAlignment(Pos.CENTER);
        
        Label title = new Label("VBox Layout - Vertical Stack");
        title.setStyle("-fx-font-weight: bold;");
        
        Button btn1 = new Button("Button 1");
        Button btn2 = new Button("Button 2 (Longer)");
        Button btn3 = new Button("Button 3");
        
        // Demonstrate VBox properties
        VBox.setVgrow(btn2, Priority.ALWAYS); // Button 2 will grow vertically
        
        vbox.getChildren().addAll(title, btn1, btn2, btn3);
        return vbox;
    }
    
    private HBox createHBoxDemo() {
        VBox container = new VBox(20);
        container.setPadding(new Insets(20));
        
        Label title = new Label("HBox Layout - Horizontal Stack");
        title.setStyle("-fx-font-weight: bold;");
        
        HBox hbox = new HBox(10);
        hbox.setAlignment(Pos.CENTER);
        
        Button btn1 = new Button("Button 1");
        Button btn2 = new Button("Button 2");
        Button btn3 = new Button("Button 3");
        
        // Demonstrate HBox properties
        HBox.setHgrow(btn2, Priority.ALWAYS); // Button 2 will grow horizontally
        btn2.setMaxWidth(Double.MAX_VALUE);
        
        hbox.getChildren().addAll(btn1, btn2, btn3);
        container.getChildren().addAll(title, hbox);
        return container;
    }
    
    private VBox createBorderPaneDemo() {
        VBox container = new VBox(10);
        container.setPadding(new Insets(20));
        
        Label title = new Label("BorderPane Layout - Five Regions");
        title.setStyle("-fx-font-weight: bold;");
        
        BorderPane borderPane = new BorderPane();
        borderPane.setPrefSize(300, 200);
        
        // Add components to different regions
        borderPane.setTop(new Label("TOP"));
        borderPane.setBottom(new Label("BOTTOM"));
        borderPane.setLeft(new Label("LEFT"));
        borderPane.setRight(new Label("RIGHT"));
        borderPane.setCenter(new Label("CENTER"));
        
        // Style the regions
        borderPane.getTop().setStyle("-fx-background-color: lightblue; -fx-padding: 10;");
        borderPane.getBottom().setStyle("-fx-background-color: lightgreen; -fx-padding: 10;");
        borderPane.getLeft().setStyle("-fx-background-color: lightcoral; -fx-padding: 10;");
        borderPane.getRight().setStyle("-fx-background-color: lightyellow; -fx-padding: 10;");
        borderPane.getCenter().setStyle("-fx-background-color: lightgray; -fx-padding: 10;");
        
        container.getChildren().addAll(title, borderPane);
        return container;
    }
    
    private VBox createGridPaneDemo() {
        VBox container = new VBox(10);
        container.setPadding(new Insets(20));
        
        Label title = new Label("GridPane Layout - Grid Structure");
        title.setStyle("-fx-font-weight: bold;");
        
        GridPane gridPane = new GridPane();
        gridPane.setHgap(10);
        gridPane.setVgap(10);
        gridPane.setPadding(new Insets(10));
        
        // Add components to specific grid positions
        gridPane.add(new Label("Name:"), 0, 0);
        gridPane.add(new TextField(), 1, 0);
        
        gridPane.add(new Label("Email:"), 0, 1);
        gridPane.add(new TextField(), 1, 1);
        
        gridPane.add(new Label("Password:"), 0, 2);
        gridPane.add(new PasswordField(), 1, 2);
        
        Button submitBtn = new Button("Submit");
        gridPane.add(submitBtn, 0, 3, 2, 1); // Span 2 columns
        
        // Make text fields grow
        ColumnConstraints col1 = new ColumnConstraints();
        ColumnConstraints col2 = new ColumnConstraints();
        col2.setHgrow(Priority.ALWAYS);
        gridPane.getColumnConstraints().addAll(col1, col2);
        
        container.getChildren().addAll(title, gridPane);
        return container;
    }
    
    private VBox createStackPaneDemo() {
        VBox container = new VBox(10);
        container.setPadding(new Insets(20));
        
        Label title = new Label("StackPane Layout - Stacked Components");
        title.setStyle("-fx-font-weight: bold;");
        
        StackPane stackPane = new StackPane();
        stackPane.setPrefSize(200, 150);
        
        // Create layered components
        Label background = new Label("Background Layer");
        background.setStyle("-fx-background-color: lightblue; -fx-font-size: 16px;");
        background.setPrefSize(180, 130);
        
        Label foreground = new Label("Foreground Layer");
        foreground.setStyle("-fx-background-color: rgba(255, 255, 255, 0.8); " +
                          "-fx-border-color: black; -fx-padding: 10;");
        
        stackPane.getChildren().addAll(background, foreground);
        
        container.getChildren().addAll(title, stackPane);
        return container;
    }
    
    private VBox createFlowPaneDemo() {
        VBox container = new VBox(10);
        container.setPadding(new Insets(20));
        
        Label title = new Label("FlowPane Layout - Flowing Components");
        title.setStyle("-fx-font-weight: bold;");
        
        FlowPane flowPane = new FlowPane();
        flowPane.setHgap(10);
        flowPane.setVgap(10);
        flowPane.setPrefWrapLength(250); // Wrap after 250 pixels
        
        // Add various sized buttons
        for (int i = 1; i <= 12; i++) {
            Button btn = new Button("Button " + i);
            if (i % 3 == 0) {
                btn.setPrefWidth(80);
            } else if (i % 2 == 0) {
                btn.setPrefWidth(60);
            }
            flowPane.getChildren().add(btn);
        }
        
        container.getChildren().addAll(title, flowPane);
        return container;
    }
    
    public static void main(String[] args) {
        launch(args);
    }
}

Event Handling

JavaFX provides multiple ways to handle user events.

Event Handling Mechanisms

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.input.KeyEvent;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class EventHandlingDemo extends Application {
    
    private TextArea logArea;
    
    @Override
    public void start(Stage primaryStage) {
        VBox root = new VBox(10);
        root.setStyle("-fx-padding: 20;");
        
        // Log area to show events
        logArea = new TextArea();
        logArea.setPrefRowCount(10);
        logArea.setEditable(false);
        
        // 1. Lambda expression event handling
        Button lambdaButton = new Button("Lambda Event Handler");
        lambdaButton.setOnAction(e -> log("Lambda button clicked!"));
        
        // 2. Method reference event handling
        Button methodRefButton = new Button("Method Reference Handler");
        methodRefButton.setOnAction(this::handleMethodRefButton);
        
        // 3. Anonymous class event handling
        Button anonymousButton = new Button("Anonymous Class Handler");
        anonymousButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
                log("Anonymous class button clicked!");
            }
        });
        
        // 4. Multiple event types on same control
        Button multiEventButton = new Button("Multi-Event Button");
        
        // Mouse events
        multiEventButton.setOnMouseEntered(e -> log("Mouse entered button"));
        multiEventButton.setOnMouseExited(e -> log("Mouse exited button"));
        multiEventButton.setOnMousePressed(e -> log("Mouse pressed on button"));
        multiEventButton.setOnMouseReleased(e -> log("Mouse released on button"));
        
        // Action event
        multiEventButton.setOnAction(e -> log("Multi-event button clicked!"));
        
        // 5. TextField with key events
        TextField textField = new TextField();
        textField.setPromptText("Type here to see key events");
        
        textField.setOnKeyPressed(e -> log("Key pressed: " + e.getCode()));
        textField.setOnKeyReleased(e -> log("Key released: " + e.getCode()));
        textField.setOnKeyTyped(e -> log("Key typed: '" + e.getCharacter() + "'"));
        
        // Text change listener
        textField.textProperty().addListener((obs, oldText, newText) -> 
            log("Text changed from '" + oldText + "' to '" + newText + "'"));
        
        // 6. CheckBox with change listener
        CheckBox checkBox = new CheckBox("Check me");
        checkBox.selectedProperty().addListener((obs, wasSelected, isSelected) -> 
            log("CheckBox " + (isSelected ? "checked" : "unchecked")));
        
        // 7. Slider with value change listener
        Slider slider = new Slider(0, 100, 50);
        slider.setShowTickLabels(true);
        slider.setShowTickMarks(true);
        
        Label sliderValueLabel = new Label("Value: 50");
        slider.valueProperty().addListener((obs, oldVal, newVal) -> {
            int value = newVal.intValue();
            sliderValueLabel.setText("Value: " + value);
            log("Slider value changed to: " + value);
        });
        
        // 8. ComboBox selection event
        ComboBox<String> comboBox = new ComboBox<>();
        comboBox.getItems().addAll("Option 1", "Option 2", "Option 3");
        comboBox.setPromptText("Select an option");
        
        comboBox.setOnAction(e -> log("ComboBox selection: " + comboBox.getValue()));
        
        // 9. Custom event handling with event filters
        Button filterButton = new Button("Event Filter Demo");
        
        // Add event filter (runs before event handlers)
        filterButton.addEventFilter(MouseEvent.MOUSE_CLICKED, e -> {
            log("Event filter: Mouse click intercepted");
            if (e.isControlDown()) {
                log("Ctrl+Click detected - consuming event");
                e.consume(); // Prevent further processing
            }
        });
        
        // Regular event handler
        filterButton.setOnMouseClicked(e -> log("Event handler: Button clicked"));
        
        // Clear log button
        Button clearButton = new Button("Clear Log");
        clearButton.setOnAction(e -> logArea.clear());
        
        root.getChildren().addAll(
            new Label("Event Handling Demo - Check the log area below:"),
            lambdaButton,
            methodRefButton,
            anonymousButton,
            multiEventButton,
            new Separator(),
            new Label("TextField (with key events):"),
            textField,
            checkBox,
            new Label("Slider (with value change listener):"),
            slider,
            sliderValueLabel,
            new Label("ComboBox (with selection event):"),
            comboBox,
            new Separator(),
            filterButton,
            new Label("(Try Ctrl+Click on the filter button)"),
            new Separator(),
            clearButton,
            new Label("Event Log:"),
            logArea
        );
        
        Scene scene = new Scene(new ScrollPane(root), 500, 700);
        primaryStage.setTitle("Event Handling Demo");
        primaryStage.setScene(scene);
        primaryStage.show();
        
        log("Application started - ready for events!");
    }
    
    private void handleMethodRefButton(ActionEvent event) {
        log("Method reference button clicked!");
    }
    
    private void log(String message) {
        logArea.appendText("[" + System.currentTimeMillis() % 10000 + "] " + message + "\n");
        logArea.setScrollTop(Double.MAX_VALUE); // Scroll to bottom
    }
    
    public static void main(String[] args) {
        launch(args);
    }
}

CSS Styling

JavaFX supports CSS for styling applications.

CSS Styling Examples

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class CSSStyleDemo extends Application {
    
    @Override
    public void start(Stage primaryStage) {
        VBox root = new VBox(20);
        root.setStyle("-fx-padding: 30; -fx-background-color: #f0f0f0;");
        
        // Title with inline CSS
        Label title = new Label("JavaFX CSS Styling Demo");
        title.setStyle("-fx-font-size: 24px; " +
                      "-fx-font-weight: bold; " +
                      "-fx-text-fill: #2c3e50; " +
                      "-fx-alignment: center;");
        
        // Styled buttons
        Button primaryButton = new Button("Primary Button");
        primaryButton.setStyle(
            "-fx-background-color: #3498db; " +
            "-fx-text-fill: white; " +
            "-fx-font-size: 14px; " +
            "-fx-padding: 10 20; " +
            "-fx-background-radius: 5; " +
            "-fx-cursor: hand;"
        );
        
        Button successButton = new Button("Success Button");
        successButton.setStyle(
            "-fx-background-color: #27ae60; " +
            "-fx-text-fill: white; " +
            "-fx-font-size: 14px; " +
            "-fx-padding: 10 20; " +
            "-fx-background-radius: 5; " +
            "-fx-cursor: hand;"
        );
        
        Button warningButton = new Button("Warning Button");
        warningButton.setStyle(
            "-fx-background-color: #f39c12; " +
            "-fx-text-fill: white; " +
            "-fx-font-size: 14px; " +
            "-fx-padding: 10 20; " +
            "-fx-background-radius: 5; " +
            "-fx-cursor: hand;"
        );
        
        Button dangerButton = new Button("Danger Button");
        dangerButton.setStyle(
            "-fx-background-color: #e74c3c; " +
            "-fx-text-fill: white; " +
            "-fx-font-size: 14px; " +
            "-fx-padding: 10 20; " +
            "-fx-background-radius: 5; " +
            "-fx-cursor: hand;"
        );
        
        // Styled text field
        TextField styledTextField = new TextField();
        styledTextField.setPromptText("Styled text field");
        styledTextField.setStyle(
            "-fx-background-color: white; " +
            "-fx-border-color: #bdc3c7; " +
            "-fx-border-width: 2; " +
            "-fx-border-radius: 5; " +
            "-fx-padding: 10; " +
            "-fx-font-size: 14px;"
        );
        
        // Focus styling
        styledTextField.focusedProperty().addListener((obs, wasFocused, isFocused) -> {
            if (isFocused) {
                styledTextField.setStyle(
                    "-fx-background-color: white; " +
                    "-fx-border-color: #3498db; " +
                    "-fx-border-width: 2; " +
                    "-fx-border-radius: 5; " +
                    "-fx-padding: 10; " +
                    "-fx-font-size: 14px;"
                );
            } else {
                styledTextField.setStyle(
                    "-fx-background-color: white; " +
                    "-fx-border-color: #bdc3c7; " +
                    "-fx-border-width: 2; " +
                    "-fx-border-radius: 5; " +
                    "-fx-padding: 10; " +
                    "-fx-font-size: 14px;"
                );
            }
        });
        
        // Styled text area
        TextArea styledTextArea = new TextArea();
        styledTextArea.setPromptText("Styled text area with custom styling");
        styledTextArea.setPrefRowCount(4);
        styledTextArea.setStyle(
            "-fx-background-color: #ecf0f1; " +
            "-fx-control-inner-background: #ecf0f1; " +
            "-fx-border-color: #95a5a6; " +
            "-fx-border-width: 2; " +
            "-fx-border-radius: 5; " +
            "-fx-font-family: 'Courier New'; " +
            "-fx-font-size: 12px;"
        );
        
        // CSS with hover effects using pseudoclasses
        Button hoverButton = new Button("Hover Effect Button");
        hoverButton.setStyle(
            "-fx-background-color: #9b59b6; " +
            "-fx-text-fill: white; " +
            "-fx-font-size: 14px; " +
            "-fx-padding: 15 25; " +
            "-fx-background-radius: 25; " +
            "-fx-cursor: hand; " +
            "-fx-effect: dropshadow(gaussian, rgba(0,0,0,0.3), 10, 0.5, 0.0, 1.0);"
        );
        
        // Hover effects using mouse events (since inline CSS can't handle :hover)
        hoverButton.setOnMouseEntered(e -> {
            hoverButton.setStyle(
                "-fx-background-color: #8e44ad; " +
                "-fx-text-fill: white; " +
                "-fx-font-size: 14px; " +
                "-fx-padding: 15 25; " +
                "-fx-background-radius: 25; " +
                "-fx-cursor: hand; " +
                "-fx-scale-x: 1.05; " +
                "-fx-scale-y: 1.05; " +
                "-fx-effect: dropshadow(gaussian, rgba(0,0,0,0.5), 15, 0.5, 0.0, 2.0);"
            );
        });
        
        hoverButton.setOnMouseExited(e -> {
            hoverButton.setStyle(
                "-fx-background-color: #9b59b6; " +
                "-fx-text-fill: white; " +
                "-fx-font-size: 14px; " +
                "-fx-padding: 15 25; " +
                "-fx-background-radius: 25; " +
                "-fx-cursor: hand; " +
                "-fx-scale-x: 1.0; " +
                "-fx-scale-y: 1.0; " +
                "-fx-effect: dropshadow(gaussian, rgba(0,0,0,0.3), 10, 0.5, 0.0, 1.0);"
            );
        });
        
        // Theme toggle button
        Button themeButton = new Button("Toggle Dark Theme");
        themeButton.setStyle(
            "-fx-background-color: #34495e; " +
            "-fx-text-fill: white; " +
            "-fx-font-size: 12px; " +
            "-fx-padding: 8 15; " +
            "-fx-background-radius: 3;"
        );
        
        boolean[] isDarkTheme = {false};
        themeButton.setOnAction(e -> {
            if (!isDarkTheme[0]) {
                // Apply dark theme
                root.setStyle("-fx-padding: 30; -fx-background-color: #2c3e50;");
                title.setStyle("-fx-font-size: 24px; -fx-font-weight: bold; -fx-text-fill: #ecf0f1;");
                themeButton.setText("Toggle Light Theme");
                isDarkTheme[0] = true;
            } else {
                // Apply light theme
                root.setStyle("-fx-padding: 30; -fx-background-color: #f0f0f0;");
                title.setStyle("-fx-font-size: 24px; -fx-font-weight: bold; -fx-text-fill: #2c3e50;");
                themeButton.setText("Toggle Dark Theme");
                isDarkTheme[0] = false;
            }
        });
        
        root.getChildren().addAll(
            title,
            new Separator(),
            primaryButton,
            successButton,
            warningButton,
            dangerButton,
            new Separator(),
            new Label("Styled Input Controls:"),
            styledTextField,
            styledTextArea,
            new Separator(),
            hoverButton,
            new Separator(),
            themeButton
        );
        
        Scene scene = new Scene(root, 400, 600);
        primaryStage.setTitle("CSS Styling Demo");
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    
    public static void main(String[] args) {
        launch(args);
    }
}

TableView and Data Binding

TableView is used for displaying tabular data with sorting and editing capabilities.

import javafx.application.Application;
import javafx.beans.property.*;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.control.cell.TextFieldTableCell;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.util.converter.IntegerStringConverter;

public class TableViewDemo extends Application {
    
    // Person model class with JavaFX properties
    public static class Person {
        private final StringProperty name;
        private final IntegerProperty age;
        private final StringProperty email;
        private final BooleanProperty active;
        
        public Person(String name, int age, String email, boolean active) {
            this.name = new SimpleStringProperty(name);
            this.age = new SimpleIntegerProperty(age);
            this.email = new SimpleStringProperty(email);
            this.active = new SimpleBooleanProperty(active);
        }
        
        // Property getters (required for TableView binding)
        public StringProperty nameProperty() { return name; }
        public IntegerProperty ageProperty() { return age; }
        public StringProperty emailProperty() { return email; }
        public BooleanProperty activeProperty() { return active; }
        
        // Value getters and setters
        public String getName() { return name.get(); }
        public void setName(String name) { this.name.set(name); }
        
        public int getAge() { return age.get(); }
        public void setAge(int age) { this.age.set(age); }
        
        public String getEmail() { return email.get(); }
        public void setEmail(String email) { this.email.set(email); }
        
        public boolean isActive() { return active.get(); }
        public void setActive(boolean active) { this.active.set(active); }
    }
    
    private TableView<Person> tableView;
    private ObservableList<Person> data;
    
    @Override
    public void start(Stage primaryStage) {
        VBox root = new VBox(10);
        root.setStyle("-fx-padding: 20;");
        
        // Create sample data
        data = FXCollections.observableArrayList(
            new Person("Alice Johnson", 25, "alice@example.com", true),
            new Person("Bob Smith", 30, "bob@example.com", true),
            new Person("Charlie Brown", 35, "charlie@example.com", false),
            new Person("Diana Prince", 28, "diana@example.com", true),
            new Person("Eve Wilson", 32, "eve@example.com", false)
        );
        
        // Create TableView
        tableView = new TableView<>();
        tableView.setEditable(true); // Enable editing
        
        // Create columns
        TableColumn<Person, String> nameColumn = new TableColumn<>("Name");
        nameColumn.setCellValueFactory(new PropertyValueFactory<>("name"));
        nameColumn.setCellFactory(TextFieldTableCell.forTableColumn());
        nameColumn.setOnEditCommit(event -> {
            event.getRowValue().setName(event.getNewValue());
            showAlert("Name updated to: " + event.getNewValue());
        });
        nameColumn.setPrefWidth(150);
        
        TableColumn<Person, Integer> ageColumn = new TableColumn<>("Age");
        ageColumn.setCellValueFactory(new PropertyValueFactory<>("age"));
        ageColumn.setCellFactory(TextFieldTableCell.forTableColumn(new IntegerStringConverter()));
        ageColumn.setOnEditCommit(event -> {
            event.getRowValue().setAge(event.getNewValue());
            showAlert("Age updated to: " + event.getNewValue());
        });
        ageColumn.setPrefWidth(80);
        
        TableColumn<Person, String> emailColumn = new TableColumn<>("Email");
        emailColumn.setCellValueFactory(new PropertyValueFactory<>("email"));
        emailColumn.setCellFactory(TextFieldTableCell.forTableColumn());
        emailColumn.setOnEditCommit(event -> {
            event.getRowValue().setEmail(event.getNewValue());
            showAlert("Email updated to: " + event.getNewValue());
        });
        emailColumn.setPrefWidth(200);
        
        TableColumn<Person, Boolean> activeColumn = new TableColumn<>("Active");
        activeColumn.setCellValueFactory(new PropertyValueFactory<>("active"));
        activeColumn.setCellFactory(col -> new TableCell<Person, Boolean>() {
            private final CheckBox checkBox = new CheckBox();
            
            {
                checkBox.setOnAction(e -> {
                    Person person = getTableRow().getItem();
                    if (person != null) {
                        person.setActive(checkBox.isSelected());
                        showAlert(person.getName() + " is now " + 
                                (checkBox.isSelected() ? "active" : "inactive"));
                    }
                });
            }
            
            @Override
            protected void updateItem(Boolean item, boolean empty) {
                super.updateItem(item, empty);
                if (empty || item == null) {
                    setGraphic(null);
                } else {
                    checkBox.setSelected(item);
                    setGraphic(checkBox);
                }
            }
        });
        activeColumn.setPrefWidth(80);
        
        // Add columns to table
        tableView.getColumns().addAll(nameColumn, ageColumn, emailColumn, activeColumn);
        
        // Set data
        tableView.setItems(data);
        
        // Create control buttons
        HBox buttonBox = new HBox(10);
        
        Button addButton = new Button("Add Person");
        addButton.setOnAction(e -> addPerson());
        
        Button removeButton = new Button("Remove Selected");
        removeButton.setOnAction(e -> removeSelectedPerson());
        
        Button showSelectionButton = new Button("Show Selection");
        showSelectionButton.setOnAction(e -> showSelectedPerson());
        
        Button clearSelectionButton = new Button("Clear Selection");
        clearSelectionButton.setOnAction(e -> tableView.getSelectionModel().clearSelection());
        
        Button sortByNameButton = new Button("Sort by Name");
        sortByNameButton.setOnAction(e -> {
            nameColumn.setSortType(TableColumn.SortType.ASCENDING);
            tableView.getSortOrder().clear();
            tableView.getSortOrder().add(nameColumn);
        });
        
        buttonBox.getChildren().addAll(addButton, removeButton, showSelectionButton, 
                                      clearSelectionButton, sortByNameButton);
        
        // Statistics label
        Label statsLabel = new Label();
        updateStatsLabel(statsLabel);
        
        // Listen for data changes to update statistics
        data.addListener((javafx.collections.ListChangeListener<Person>) change -> 
            updateStatsLabel(statsLabel));
        
        // Selection listener
        tableView.getSelectionModel().selectedItemProperty().addListener(
            (obs, oldSelection, newSelection) -> {
                if (newSelection != null) {
                    System.out.println("Selected: " + newSelection.getName());
                }
            });
        
        root.getChildren().addAll(
            new Label("TableView Demo - Double-click cells to edit"),
            tableView,
            buttonBox,
            new Separator(),
            statsLabel
        );
        
        Scene scene = new Scene(root, 600, 500);
        primaryStage.setTitle("JavaFX TableView Demo");
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    
    private void addPerson() {
        // Create a dialog to get person details
        Dialog<Person> dialog = new Dialog<>();
        dialog.setTitle("Add New Person");
        dialog.setHeaderText("Enter person details:");
        
        // Create form fields
        TextField nameField = new TextField();
        nameField.setPromptText("Name");
        TextField ageField = new TextField();
        ageField.setPromptText("Age");
        TextField emailField = new TextField();
        emailField.setPromptText("Email");
        CheckBox activeCheckBox = new CheckBox("Active");
        activeCheckBox.setSelected(true);
        
        VBox form = new VBox(10);
        form.getChildren().addAll(
            new Label("Name:"), nameField,
            new Label("Age:"), ageField,
            new Label("Email:"), emailField,
            activeCheckBox
        );
        
        dialog.getDialogPane().setContent(form);
        dialog.getDialogPane().getButtonTypes().addAll(ButtonType.OK, ButtonType.CANCEL);
        
        dialog.setResultConverter(buttonType -> {
            if (buttonType == ButtonType.OK) {
                try {
                    String name = nameField.getText().trim();
                    int age = Integer.parseInt(ageField.getText().trim());
                    String email = emailField.getText().trim();
                    boolean active = activeCheckBox.isSelected();
                    
                    if (!name.isEmpty() && !email.isEmpty()) {
                        return new Person(name, age, email, active);
                    }
                } catch (NumberFormatException e) {
                    showAlert("Invalid age format");
                }
            }
            return null;
        });
        
        dialog.showAndWait().ifPresent(person -> {
            data.add(person);
            showAlert("Added: " + person.getName());
        });
    }
    
    private void removeSelectedPerson() {
        Person selected = tableView.getSelectionModel().getSelectedItem();
        if (selected != null) {
            data.remove(selected);
            showAlert("Removed: " + selected.getName());
        } else {
            showAlert("No person selected");
        }
    }
    
    private void showSelectedPerson() {
        Person selected = tableView.getSelectionModel().getSelectedItem();
        if (selected != null) {
            String info = String.format("Selected Person:\nName: %s\nAge: %d\nEmail: %s\nActive: %s",
                                      selected.getName(), selected.getAge(), 
                                      selected.getEmail(), selected.isActive());
            showAlert(info);
        } else {
            showAlert("No person selected");
        }
    }
    
    private void updateStatsLabel(Label statsLabel) {
        long activeCount = data.stream().mapToLong(p -> p.isActive() ? 1 : 0).sum();
        double averageAge = data.stream().mapToInt(Person::getAge).average().orElse(0);
        
        statsLabel.setText(String.format("Total: %d | Active: %d | Average Age: %.1f", 
                                        data.size(), activeCount, averageAge));
    }
    
    private void showAlert(String message) {
        Alert alert = new Alert(Alert.AlertType.INFORMATION);
        alert.setTitle("Information");
        alert.setHeaderText(null);
        alert.setContentText(message);
        alert.showAndWait();
    }
    
    public static void main(String[] args) {
        launch(args);
    }
}

FXML and Scene Builder

FXML allows you to separate UI design from application logic.

FXML Example

First, create an FXML file (LoginForm.fxml):

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.geometry.Insets?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>

<VBox xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="LoginController">
   <children>
      <Label text="Login Form" style="-fx-font-size: 18px; -fx-font-weight: bold;">
         <VBox.margin>
            <Insets bottom="20.0" />
         </VBox.margin>
      </Label>
      
      <GridPane hgap="10.0" vgap="10.0">
         <columnConstraints>
            <ColumnConstraints minWidth="80.0" />
            <ColumnConstraints hgrow="ALWAYS" />
         </columnConstraints>
         
         <children>
            <Label text="Username:" />
            <TextField fx:id="usernameField" promptText="Enter username" GridPane.columnIndex="1" />
            
            <Label text="Password:" GridPane.rowIndex="1" />
            <PasswordField fx:id="passwordField" promptText="Enter password" GridPane.columnIndex="1" GridPane.rowIndex="1" />
            
            <CheckBox fx:id="rememberMeCheckBox" text="Remember me" GridPane.columnIndex="1" GridPane.rowIndex="2" />
         </children>
         
         <VBox.margin>
            <Insets bottom="20.0" />
         </VBox.margin>
      </GridPane>
      
      <HBox spacing="10.0" alignment="CENTER">
         <children>
            <Button fx:id="loginButton" text="Login" onAction="#handleLogin" prefWidth="80.0" />
            <Button fx:id="cancelButton" text="Cancel" onAction="#handleCancel" prefWidth="80.0" />
         </children>
      </HBox>
      
      <Label fx:id="statusLabel" text="" style="-fx-text-fill: red;">
         <VBox.margin>
            <Insets top="10.0" />
         </VBox.margin>
      </Label>
   </children>
   
   <padding>
      <Insets bottom="30.0" left="30.0" right="30.0" top="30.0" />
   </padding>
</VBox>

Now, the controller class:

import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.*;
import javafx.event.ActionEvent;
import java.net.URL;
import java.util.ResourceBundle;

public class LoginController implements Initializable {
    
    @FXML
    private TextField usernameField;
    
    @FXML
    private PasswordField passwordField;
    
    @FXML
    private CheckBox rememberMeCheckBox;
    
    @FXML
    private Button loginButton;
    
    @FXML
    private Button cancelButton;
    
    @FXML
    private Label statusLabel;
    
    @Override
    public void initialize(URL location, ResourceBundle resources) {
        // Initialize the controller
        System.out.println("LoginController initialized");
        
        // Add listeners
        usernameField.textProperty().addListener((obs, oldText, newText) -> {
            clearStatus();
            updateLoginButtonState();
        });
        
        passwordField.textProperty().addListener((obs, oldText, newText) -> {
            clearStatus();
            updateLoginButtonState();
        });
        
        updateLoginButtonState();
    }
    
    @FXML
    private void handleLogin(ActionEvent event) {
        String username = usernameField.getText().trim();
        String password = passwordField.getText();
        boolean rememberMe = rememberMeCheckBox.isSelected();
        
        if (username.isEmpty() || password.isEmpty()) {
            showStatus("Please enter both username and password", "error");
            return;
        }
        
        // Simple validation (in real app, this would be more secure)
        if ("admin".equals(username) && "password".equals(password)) {
            showStatus("Login successful!", "success");
            System.out.println("Remember me: " + rememberMe);
            
            // Close the login window or navigate to main application
            loginButton.getScene().getWindow().hide();
        } else {
            showStatus("Invalid username or password", "error");
        }
    }
    
    @FXML
    private void handleCancel(ActionEvent event) {
        // Clear fields
        usernameField.clear();
        passwordField.clear();
        rememberMeCheckBox.setSelected(false);
        clearStatus();
        
        // Or close the window
        // cancelButton.getScene().getWindow().hide();
    }
    
    private void showStatus(String message, String type) {
        statusLabel.setText(message);
        if ("error".equals(type)) {
            statusLabel.setStyle("-fx-text-fill: red;");
        } else if ("success".equals(type)) {
            statusLabel.setStyle("-fx-text-fill: green;");
        }
    }
    
    private void clearStatus() {
        statusLabel.setText("");
    }
    
    private void updateLoginButtonState() {
        boolean isValid = !usernameField.getText().trim().isEmpty() && 
                         !passwordField.getText().isEmpty();
        loginButton.setDisable(!isValid);
    }
}

Main application class to load FXML:

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class FXMLDemo extends Application {
    
    @Override
    public void start(Stage primaryStage) throws Exception {
        // Load FXML file
        FXMLLoader loader = new FXMLLoader(getClass().getResource("/LoginForm.fxml"));
        Parent root = loader.load();
        
        // Get controller if needed
        LoginController controller = loader.getController();
        
        Scene scene = new Scene(root);
        primaryStage.setTitle("FXML Login Demo");
        primaryStage.setScene(scene);
        primaryStage.setResizable(false);
        primaryStage.show();
    }
    
    public static void main(String[] args) {
        launch(args);
    }
}

Hands-on Exercise 1: Student Registration Form

Create a comprehensive student registration form using JavaFX:

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;

public class StudentRegistrationForm extends Application {
    
    // TODO: Create a student registration form with the following fields:
    // - Personal Information: Name, Age, Gender (RadioButtons), Date of Birth (DatePicker)
    // - Contact Information: Email, Phone, Address (TextArea)
    // - Academic Information: Course (ComboBox), Year (ComboBox), GPA (Slider)
    // - Additional: Interests (CheckBoxes), Comments (TextArea)
    // - Buttons: Register, Clear, Cancel
    
    @Override
    public void start(Stage primaryStage) {
        // TODO: Implement the registration form
        // Use appropriate layout managers (GridPane recommended)
        // Add validation for required fields
        // Show confirmation dialog when registration is successful
        // Implement clear functionality to reset all fields
        
        primaryStage.setTitle("Student Registration Form");
        primaryStage.show();
    }
    
    // TODO: Add validation methods
    // TODO: Add event handlers for buttons
    // TODO: Add a method to collect and display form data
    
    public static void main(String[] args) {
        launch(args);
    }
}

Hands-on Exercise 2: Simple Calculator

Create a functional calculator application:

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;

public class SimpleCalculator extends Application {
    
    // TODO: Create a calculator with:
    // - Display area (TextField, read-only)
    // - Number buttons (0-9)
    // - Operation buttons (+, -, *, /, =)
    // - Clear button (C), Clear All (CA)
    // - Decimal point button
    
    private TextField display;
    private double currentValue = 0;
    private String currentOperation = "";
    private boolean operationPressed = false;
    
    @Override
    public void start(Stage primaryStage) {
        // TODO: Create the calculator UI
        // Use GridPane for button layout
        // Style buttons for better appearance
        // Implement calculation logic
        
        primaryStage.setTitle("Simple Calculator");
        primaryStage.show();
    }
    
    // TODO: Implement button event handlers
    // TODO: Implement calculation logic
    // TODO: Handle edge cases (division by zero, etc.)
    
    public static void main(String[] args) {
        launch(args);
    }
}

Exercise Solutions: Student Registration Form

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;
import java.time.LocalDate;

public class StudentRegistrationFormSolution extends Application {
    
    private TextField nameField;
    private Spinner<Integer> ageSpinner;
    private ToggleGroup genderGroup;
    private DatePicker dobPicker;
    private TextField emailField;
    private TextField phoneField;
    private TextArea addressArea;
    private ComboBox<String> courseCombo;
    private ComboBox<String> yearCombo;
    private Slider gpaSlider;
    private Label gpaLabel;
    private CheckBox sportsCheckBox;
    private CheckBox musicCheckBox;
    private CheckBox readingCheckBox;
    private TextArea commentsArea;
    
    @Override
    public void start(Stage primaryStage) {
        VBox root = new VBox(20);
        root.setPadding(new Insets(20));
        
        // Title
        Label titleLabel = new Label("Student Registration Form");
        titleLabel.setStyle("-fx-font-size: 20px; -fx-font-weight: bold;");
        
        // Create form sections
        VBox personalSection = createPersonalSection();
        VBox contactSection = createContactSection();
        VBox academicSection = createAcademicSection();
        VBox additionalSection = createAdditionalSection();
        HBox buttonSection = createButtonSection();
        
        root.getChildren().addAll(titleLabel, personalSection, contactSection, 
                                 academicSection, additionalSection, buttonSection);
        
        Scene scene = new Scene(new ScrollPane(root), 500, 700);
        primaryStage.setTitle("Student Registration");
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    
    private VBox createPersonalSection() {
        VBox section = new VBox(10);
        section.getChildren().add(new Label("Personal Information:"));
        section.setStyle("-fx-border-color: lightgray; -fx-border-width: 1; -fx-padding: 10;");
        
        GridPane grid = new GridPane();
        grid.setHgap(10);
        grid.setVgap(10);
        
        // Name
        grid.add(new Label("Name:"), 0, 0);
        nameField = new TextField();
        grid.add(nameField, 1, 0);
        
        // Age
        grid.add(new Label("Age:"), 0, 1);
        ageSpinner = new Spinner<>(16, 100, 18);
        grid.add(ageSpinner, 1, 1);
        
        // Gender
        grid.add(new Label("Gender:"), 0, 2);
        genderGroup = new ToggleGroup();
        RadioButton maleRadio = new RadioButton("Male");
        RadioButton femaleRadio = new RadioButton("Female");
        maleRadio.setToggleGroup(genderGroup);
        femaleRadio.setToggleGroup(genderGroup);
        HBox genderBox = new HBox(10, maleRadio, femaleRadio);
        grid.add(genderBox, 1, 2);
        
        // Date of Birth
        grid.add(new Label("Date of Birth:"), 0, 3);
        dobPicker = new DatePicker();
        grid.add(dobPicker, 1, 3);
        
        section.getChildren().add(grid);
        return section;
    }
    
    private VBox createContactSection() {
        VBox section = new VBox(10);
        section.getChildren().add(new Label("Contact Information:"));
        section.setStyle("-fx-border-color: lightgray; -fx-border-width: 1; -fx-padding: 10;");
        
        GridPane grid = new GridPane();
        grid.setHgap(10);
        grid.setVgap(10);
        
        // Email
        grid.add(new Label("Email:"), 0, 0);
        emailField = new TextField();
        grid.add(emailField, 1, 0);
        
        // Phone
        grid.add(new Label("Phone:"), 0, 1);
        phoneField = new TextField();
        grid.add(phoneField, 1, 1);
        
        // Address
        grid.add(new Label("Address:"), 0, 2);
        addressArea = new TextArea();
        addressArea.setPrefRowCount(3);
        grid.add(addressArea, 1, 2);
        
        // Make second column grow
        ColumnConstraints col1 = new ColumnConstraints();
        ColumnConstraints col2 = new ColumnConstraints();
        col2.setHgrow(Priority.ALWAYS);
        grid.getColumnConstraints().addAll(col1, col2);
        
        section.getChildren().add(grid);
        return section;
    }
    
    private VBox createAcademicSection() {
        VBox section = new VBox(10);
        section.getChildren().add(new Label("Academic Information:"));
        section.setStyle("-fx-border-color: lightgray; -fx-border-width: 1; -fx-padding: 10;");
        
        GridPane grid = new GridPane();
        grid.setHgap(10);
        grid.setVgap(10);
        
        // Course
        grid.add(new Label("Course:"), 0, 0);
        courseCombo = new ComboBox<>();
        courseCombo.getItems().addAll("Computer Science", "Information Technology", 
                                     "Electronics", "Mechanical", "Civil");
        grid.add(courseCombo, 1, 0);
        
        // Year
        grid.add(new Label("Year:"), 0, 1);
        yearCombo = new ComboBox<>();
        yearCombo.getItems().addAll("1st Year", "2nd Year", "3rd Year");
        grid.add(yearCombo, 1, 1);
        
        // GPA
        grid.add(new Label("GPA:"), 0, 2);
        gpaSlider = new Slider(0, 10, 7);
        gpaSlider.setShowTickLabels(true);
        gpaSlider.setShowTickMarks(true);
        gpaSlider.setMajorTickUnit(2);
        gpaLabel = new Label("7.0");
        gpaSlider.valueProperty().addListener((obs, oldVal, newVal) -> 
            gpaLabel.setText(String.format("%.1f", newVal.doubleValue())));
        
        VBox gpaBox = new VBox(5, gpaSlider, gpaLabel);
        grid.add(gpaBox, 1, 2);
        
        ColumnConstraints col1 = new ColumnConstraints();
        ColumnConstraints col2 = new ColumnConstraints();
        col2.setHgrow(Priority.ALWAYS);
        grid.getColumnConstraints().addAll(col1, col2);
        
        section.getChildren().add(grid);
        return section;
    }
    
    private VBox createAdditionalSection() {
        VBox section = new VBox(10);
        section.getChildren().add(new Label("Additional Information:"));
        section.setStyle("-fx-border-color: lightgray; -fx-border-width: 1; -fx-padding: 10;");
        
        // Interests
        Label interestsLabel = new Label("Interests:");
        sportsCheckBox = new CheckBox("Sports");
        musicCheckBox = new CheckBox("Music");
        readingCheckBox = new CheckBox("Reading");
        HBox interestsBox = new HBox(10, sportsCheckBox, musicCheckBox, readingCheckBox);
        
        // Comments
        Label commentsLabel = new Label("Comments:");
        commentsArea = new TextArea();
        commentsArea.setPrefRowCount(3);
        commentsArea.setPromptText("Any additional information...");
        
        section.getChildren().addAll(interestsLabel, interestsBox, commentsLabel, commentsArea);
        return section;
    }
    
    private HBox createButtonSection() {
        HBox buttonBox = new HBox(10);
        buttonBox.setStyle("-fx-alignment: center;");
        
        Button registerButton = new Button("Register");
        registerButton.setOnAction(e -> handleRegister());
        
        Button clearButton = new Button("Clear");
        clearButton.setOnAction(e -> handleClear());
        
        Button cancelButton = new Button("Cancel");
        cancelButton.setOnAction(e -> handleCancel());
        
        buttonBox.getChildren().addAll(registerButton, clearButton, cancelButton);
        return buttonBox;
    }
    
    private void handleRegister() {
        if (!validateForm()) {
            return;
        }
        
        StringBuilder sb = new StringBuilder();
        sb.append("Registration Successful!\n\n");
        sb.append("Name: ").append(nameField.getText()).append("\n");
        sb.append("Age: ").append(ageSpinner.getValue()).append("\n");
        
        RadioButton selectedGender = (RadioButton) genderGroup.getSelectedToggle();
        if (selectedGender != null) {
            sb.append("Gender: ").append(selectedGender.getText()).append("\n");
        }
        
        if (dobPicker.getValue() != null) {
            sb.append("Date of Birth: ").append(dobPicker.getValue()).append("\n");
        }
        
        sb.append("Email: ").append(emailField.getText()).append("\n");
        sb.append("Phone: ").append(phoneField.getText()).append("\n");
        sb.append("Course: ").append(courseCombo.getValue()).append("\n");
        sb.append("Year: ").append(yearCombo.getValue()).append("\n");
        sb.append("GPA: ").append(String.format("%.1f", gpaSlider.getValue())).append("\n");
        
        Alert alert = new Alert(Alert.AlertType.INFORMATION);
        alert.setTitle("Registration Successful");
        alert.setHeaderText("Student Registered");
        alert.setContentText(sb.toString());
        alert.showAndWait();
    }
    
    private boolean validateForm() {
        if (nameField.getText().trim().isEmpty()) {
            showError("Name is required");
            return false;
        }
        
        if (emailField.getText().trim().isEmpty()) {
            showError("Email is required");
            return false;
        }
        
        if (courseCombo.getValue() == null) {
            showError("Please select a course");
            return false;
        }
        
        if (yearCombo.getValue() == null) {
            showError("Please select a year");
            return false;
        }
        
        return true;
    }
    
    private void showError(String message) {
        Alert alert = new Alert(Alert.AlertType.ERROR);
        alert.setTitle("Validation Error");
        alert.setHeaderText("Please correct the following error:");
        alert.setContentText(message);
        alert.showAndWait();
    }
    
    private void handleClear() {
        nameField.clear();
        ageSpinner.getValueFactory().setValue(18);
        genderGroup.selectToggle(null);
        dobPicker.setValue(null);
        emailField.clear();
        phoneField.clear();
        addressArea.clear();
        courseCombo.setValue(null);
        yearCombo.setValue(null);
        gpaSlider.setValue(7);
        sportsCheckBox.setSelected(false);
        musicCheckBox.setSelected(false);
        readingCheckBox.setSelected(false);
        commentsArea.clear();
    }
    
    private void handleCancel() {
        Alert alert = new Alert(Alert.AlertType.CONFIRMATION);
        alert.setTitle("Confirm Exit");
        alert.setHeaderText("Are you sure you want to exit?");
        alert.setContentText("All unsaved data will be lost.");
        
        alert.showAndWait().ifPresent(response -> {
            if (response == ButtonType.OK) {
                System.exit(0);
            }
        });
    }
    
    public static void main(String[] args) {
        launch(args);
    }
}

Summary

Key Concepts Covered

JavaFX Architecture: Stage, Scene, Scene Graph, and Nodes
Application Structure: Application lifecycle and proper initialization
UI Controls: Buttons, text fields, lists, tables, and specialized controls
Layout Managers: VBox, HBox, BorderPane, GridPane, StackPane, FlowPane
Event Handling: Action events, mouse events, key events, and property listeners
CSS Styling: Inline styles and external stylesheets
Data Binding: TableView with observable properties
FXML: Separating UI design from application logic

Benefits of JavaFX

Modern UI: Rich, responsive user interfaces
CSS Styling: Web-like styling capabilities
Data Binding: Automatic UI updates with property changes
FXML Support: Designer-developer workflow separation
Cross-platform: Runs on Windows, macOS, and Linux

Best Practices

Use appropriate layout managers for responsive design
Separate UI logic from business logic
Use data binding for dynamic UI updates
Apply consistent styling throughout the application
Handle user input validation properly
Use FXML for complex UI designs

Next Lecture Preview

Lecture 42: Final Review and Project Integration

Review of all major Java concepts covered
Best practices for Java development
Project planning and architecture
Integration of different Java technologies
Preparation for real-world development
Career guidance and next steps

Preparation

Review previous lectures and practice exercises
Think about potential project ideas
Prepare questions about Java development practices

Thank You!

Questions and Discussion

How does JavaFX compare to other UI frameworks you've used?
What are the advantages of using FXML vs pure Java code for UI design?
How can you make JavaFX applications more responsive and user-friendly?

Resources for Further Learning

Oracle JavaFX Documentation
JavaFX Scene Builder for visual UI design
OpenJFX community and resources
Practice building complete desktop applications

Next: Final Review and Project Integration