notes-shivam

unit5

4 min read

  • GUI Programming: AWT and Swing
    • [[#GUI Programming: AWT and Swing#1. Introduction to GUI Controls|1. Introduction to GUI Controls]]
    • [[#GUI Programming: AWT and Swing#2. Button|2. Button]]
    • [[#GUI Programming: AWT and Swing#3. Label|3. Label]]
    • [[#GUI Programming: AWT and Swing#4. Text Field|4. Text Field]]
    • [[#GUI Programming: AWT and Swing#5. Text Area|5. Text Area]]
    • [[#GUI Programming: AWT and Swing#6. List|6. List]]
    • [[#GUI Programming: AWT and Swing#7. Checkbox|7. Checkbox]]
    • [[#GUI Programming: AWT and Swing#8. Radio Button|8. Radio Button]]
    • [[#GUI Programming: AWT and Swing#9. Scrollbar|9. Scrollbar]]
    • [[#GUI Programming: AWT and Swing#10. Menu|10. Menu]]
  • Applet
    • [[#GUI Programming: AWT and Swing#1. Applet Concept|1. Applet Concept]]
    • [[#GUI Programming: AWT and Swing#2. Creating an Applet|2. Creating an Applet]]
    • [[#GUI Programming: AWT and Swing#3. Applet Lifecycle|3. Applet Lifecycle]]
    • [[#GUI Programming: AWT and Swing#4. Content in Applets|4. Content in Applets]]

GUI Programming: AWT and Swing

1. Introduction to GUI Controls

  • GUI (Graphical User Interface): Enables user interaction through graphical components (e.g., buttons, text fields).
  • AWT (Abstract Window Toolkit): Part of Java’s original GUI framework; uses native OS components.
  • Swing: Advanced GUI library in Java; lightweight and platform-independent.

2. Button

  • Description: Used to trigger actions/events when clicked.

  • AWT Class: Button

  • Swing Class: JButton

  • Example:

    JButton btn = new JButton("Click Me");
btn.addActionListener(e -> System.out.println("Button clicked!"));

3. Label

  • Description: Displays non-editable text or images.

  • AWT Class: Label

  • Swing Class: JLabel

  • Example:

    JLabel label = new JLabel("Welcome to GUI!");

4. Text Field

  • Description: Single-line input field for text.

  • AWT Class: TextField

  • Swing Class: JTextField

  • Example:

    JTextField textField = new JTextField(20); // 20 columns

5. Text Area

  • Description: Multi-line text input or display area.

  • AWT Class: TextArea

  • Swing Class: JTextArea

  • Example:

    JTextArea textArea = new JTextArea(5, 20); // 5 rows, 20 columns

6. List

  • Description: Displays a list of items for selection.

  • AWT Class: List

  • Swing Class: JList

  • Example:

    String[] items = {"Item1", "Item2", "Item3"};
JList<String> list = new JList<>(items);

7. Checkbox

  • Description: Used for selecting/deselecting options.

  • AWT Class: Checkbox

  • Swing Class: JCheckBox

  • Example:

    JCheckBox checkBox = new JCheckBox("Accept Terms");

8. Radio Button

  • Description: Used for mutually exclusive selection in a group.

  • Swing Class: JRadioButton (AWT doesn’t have a direct equivalent).

  • Example:

    JRadioButton rb1 = new JRadioButton("Option 1");
JRadioButton rb2 = new JRadioButton("Option 2");
ButtonGroup bg = new ButtonGroup();
bg.add(rb1);
bg.add(rb2);

9. Scrollbar

  • Description: Used to scroll content vertically or horizontally.

  • AWT Class: Scrollbar

  • Swing Alternative: JScrollBar or JScrollPane

  • Example:

    JScrollBar scrollBar = new JScrollBar(JScrollBar.HORIZONTAL);

10. Menu

  • Description: Adds drop-down menus in the application.

  • AWT Classes: Menu, MenuBar, MenuItem

  • Swing Classes: JMenu, JMenuBar, JMenuItem

  • Example:

    JMenuBar menuBar = new JMenuBar();
JMenu fileMenu = new JMenu("File");
JMenuItem openItem = new JMenuItem("Open");
fileMenu.add(openItem);
menuBar.add(fileMenu);

Would you like a sample program implementing all these components?

Applet

1. Applet Concept

  • Definition: A small Java program embedded in web pages, executed by a Java-enabled browser.
  • Framework: Part of the java.applet package; uses Applet or JApplet (Swing) class.
  • Characteristics:
    • Runs in a sandbox (restricted access).
    • Requires an HTML file to load.
    • Now outdated and replaced by modern web technologies.

2. Creating an Applet

  • Steps to Create:

    1. Extend the Applet class.
    2. Override methods like paint().
    3. Use an HTML file with the <applet> tag to run the applet.

  • Example:

    import java.applet.Applet;
import java.awt.Graphics;
 
public class SimpleApplet extends Applet {
    public void paint(Graphics g) {
        g.drawString("Hello, Applet!", 50, 50);
    }
}

  • HTML to Run:

    <applet code="SimpleApplet.class" width="300" height="200"></applet>

3. Applet Lifecycle

  • Lifecycle Methods:

    1. init(): Initializes the applet.
    2. start(): Starts or resumes the applet.
    3. paint(Graphics g): Draws graphics on the screen.
    4. stop(): Stops execution temporarily.
    5. destroy(): Cleans up resources before applet termination.

  • Execution Order: init() → start() → paint() → (stop() → start()) → destroy()

4. Content in Applets

  • Text and Graphics: Use the paint(Graphics g) method to draw text, shapes, or images.

    • Drawing Shapes:

      g.drawRect(50, 50, 100, 50); // Rectangle
g.drawOval(50, 120, 100, 50); // Oval

    • Displaying Images:

      Image img = getImage(getDocumentBase(), "image.jpg");
g.drawImage(img, 50, 50, this);

  • User Interaction: Add listeners for mouse and keyboard input.

Would you like a full applet example with interactivity?

Graph View

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