Overview of AWT

 

🪟 AWT (Abstract Window Toolkit) in Java 

📌 What is AWT?

AWT (Abstract Window Toolkit) is Java’s original platform-independent GUI (Graphical User Interface) toolkit, part of the java.awt package. It allows developers to build graphical applications like forms, buttons, text fields, and windows.

✅ AWT is part of the Java Foundation Classes (JFC).

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🧱 AWT Architecture

AWT is built on top of native code using the system's GUI libraries. So when you use AWT, you're actually calling underlying OS GUI components, which makes AWT platform-dependent in look and feel (called heavyweight components).

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🔧 Key Features of AWT

• Provides basic GUI components like Button, Label, TextField, etc.

• Event-driven programming model.

• Uses native system components (heavyweight).

• Supports layout managers for arranging GUI components.

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🔢 Core Classes and Interfaces in java.awt

Component Class	Description
Frame	Main window
Button	Push button
Label	Text label
TextField	Single-line text input
TextArea	Multi-line text area
Checkbox	Checkbox
CheckboxGroup	Radio buttons
List	Scrollable list
Choice	Dropdown menu
Canvas	For custom drawing
Panel	Container to hold other components
Scrollbar	Vertical/horizontal scroll bar

📋 Example: Simple AWT Application
import java.awt.*;
import java.awt.event.*;

public class MyAWTApp {
    public static void main(String[] args) {
        Frame f = new Frame("My First AWT Window");

        Label label = new Label("Enter Name:");
        label.setBounds(50, 50, 100, 30);

        TextField tf = new TextField();
        tf.setBounds(150, 50, 150, 30);

        Button btn = new Button("Click Me");
        btn.setBounds(100, 100, 80, 30);

        btn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println("Hello, " + tf.getText());
            }
        });

        f.add(label);
        f.add(tf);
        f.add(btn);

        f.setSize(400, 200);
        f.setLayout(null);
        f.setVisible(true);

        // Close window on clicking 'X'
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                f.dispose();
            }
        });
    }
}

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📚 Layout Managers

AWT uses layout managers to control the positioning of components:

Layout Manager	Description
FlowLayout	Left to right, wraps at end
BorderLayout	North, South, East, West, Center
GridLayout	Equal-sized grid cells
CardLayout	One component visible at a time
GridBagLayout	Flexible grid (complex)

Example:

f.setLayout(new FlowLayout());

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🎯 Event Handling in AWT

AWT uses Event Delegation Model to handle user interactions.

Key Interfaces:

• ActionListener – for buttons

• ItemListener – for checkboxes, lists

• KeyListener – for keyboard events

• MouseListener / MouseMotionListener

Example:

btn.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        // Handle click
    }
});

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⚠️ Limitations of AWT

Limitation	Description
Platform Dependent	Uses native components (inconsistent look)
Limited widgets	Lacks rich components (like trees, tables)
Heavyweight	Not lightweight like Swing or JavaFX

✅ When to Use AWT?

• For simple GUI applications

• When performance and native look and feel are desired

• In legacy applications

However, for more modern applications, Swing or JavaFX is recommended.

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