**Course Title:** Comprehensive Java Programming: From Basics to Advanced Concepts **Section Title:** Introduction to Java GUI Programming **Topic:** Design a simple GUI application using Swing or JavaFX that performs basic operations. **Objective:** Design and implement a simple GUI application using Swing or JavaFX that performs basic operations, such as calculating the area and perimeter of a rectangle. **Introduction:** In this lab topic, we will design and implement a simple GUI application using Swing or JavaFX that performs basic operations. We will use the concepts learned in the previous topics to create a functional GUI application. **Design Requirements:** * Create a GUI application with a label, two text fields, and two buttons. * The first text field should accept the length of a rectangle, and the second text field should accept the width of a rectangle. * The first button should calculate the area of the rectangle, and the second button should calculate the perimeter of the rectangle. * Display the results in a label or text area. **Implementation:** We will implement this application using both Swing and JavaFX. **Swing Implementation:** First, we will create a new class `RectangleCalculator` that extends `JFrame`: ```java import javax.swing.*; import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; public class RectangleCalculator extends JFrame { private JLabel lengthLabel; private JLabel widthLabel; private JTextField lengthField; private JTextField widthField; private JButton areaButton; private JButton perimeterButton; private JLabel resultLabel; public RectangleCalculator() { // Set up the GUI components lengthLabel = new JLabel("Length:"); widthLabel = new JLabel("Width:"); lengthField = new JTextField(10); widthField = new JTextField(10); areaButton = new JButton("Calculate Area"); perimeterButton = new JButton("Calculate Perimeter"); resultLabel = new JLabel(""); // Set up the layout JPanel panel = new JPanel(); panel.setLayout(new GridLayout(3, 2)); panel.add(lengthLabel); panel.add(lengthField); panel.add(widthLabel); panel.add(widthField); panel.add(areaButton); panel.add(perimeterButton); // Add action listeners areaButton.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { calculateArea(); } }); perimeterButton.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { calculatePerimeter(); } }); // Add the panel to the frame add(panel); setSize(300, 200); setDefaultCloseOperation(EXIT_ON_CLOSE); setVisible(true); } private void calculateArea() { try { double length = Double.parseDouble(lengthField.getText()); double width = Double.parseDouble(widthField.getText()); double area = length * width; resultLabel.setText("Area: " + area); } catch (NumberFormatException e) { JOptionPane.showMessageDialog(this, "Invalid input"); } } private void calculatePerimeter() { try { double length = Double.parseDouble(lengthField.getText()); double width = Double.parseDouble(widthField.getText()); double perimeter = 2 * (length + width); resultLabel.setText("Perimeter: " + perimeter); } catch (NumberFormatException e) { JOptionPane.showMessageDialog(this, "Invalid input"); } } public static void main(String[] args) { new RectangleCalculator(); } } ``` **JavaFX Implementation:** First, we will create a new class `RectangleCalculator` that extends `Application`: ```java import javafx.application.Application; import javafx.geometry.Insets; import javafx.geometry.Pos; import javafx.scene.Scene; import javafx.scene.control.Button; import javafx.scene.control.Label; import javafx.scene.control.TextField; import javafx.scene.layout.VBox; import javafx.stage.Stage; public class RectangleCalculator extends Application { @Override public void start(Stage primaryStage) { // Set up the GUI components Label lengthLabel = new Label("Length:"); TextField lengthField = new TextField(); Label widthLabel = new Label("Width:"); TextField widthField = new TextField(); Button areaButton = new Button("Calculate Area"); Button perimeterButton = new Button("Calculate Perimeter"); Label resultLabel = new Label(""); // Set up the layout VBox root = new VBox(10); root.getChildren().addAll(lengthLabel, lengthField, widthLabel, widthField, areaButton, perimeterButton, resultLabel); root.setPadding(new Insets(10)); // Add event handlers areaButton.setOnAction(event -> calculateArea(lengthField, widthField, resultLabel)); perimeterButton.setOnAction(event -> calculatePerimeter(lengthField, widthField, resultLabel)); // Add the scene to the stage primaryStage.setTitle("Rectangle Calculator"); primaryStage.setScene(new Scene(root, 300, 200)); primaryStage.show(); } private void calculateArea(TextField lengthField, TextField widthField, Label resultLabel) { try { double length = Double.parseDouble(lengthField.getText()); double width = Double.parseDouble(widthField.getText()); double area = length * width; resultLabel.setText("Area: " + area); } catch (NumberFormatException e) { resultLabel.setText("Invalid input"); } } private void calculatePerimeter(TextField lengthField, TextField widthField, Label resultLabel) { try { double length = Double.parseDouble(lengthField.getText()); double width = Double.parseDouble(widthField.getText()); double perimeter = 2 * (length + width); resultLabel.setText("Perimeter: " + perimeter); } catch (NumberFormatException e) { resultLabel.setText("Invalid input"); } } public static void main(String[] args) { launch(args); } } ``` **Conclusion:** In this lab topic, we designed and implemented a simple GUI application using both Swing and JavaFX that performs basic operations. We used the concepts learned in the previous topics to create a functional GUI application. **Practical Takeaways:** * Understand the differences between Swing and JavaFX. * Learn how to create GUI components and layouts using both Swing and JavaFX. * Understand how to handle events and perform calculations using GUI applications. **External Resources:** * [Java Documentation: Swing](https://docs.oracle.com/javase/tutorial/uiswing/index.html) * [Java Documentation: JavaFX](https://docs.oracle.com/javafx/2/get_started/jfxpub-get_started.htm) * [Oracle Java Tutorials: GUI Applications](https://docs.oracle.com/javase/tutorial/uiswing/comp/index.html) **Comment or Ask for Help:** If you have any questions or need help with this topic, please leave a comment below.