Frames and Windows

Creating a Frame

A Frame is a top-level window with a title bar and resize borders. Subclass it and add components in the constructor:

import java.awt.*;

public class FrameTest extends Frame {
    FrameTest() {
        setTitle("My Window");
        setSize(400, 250);
        setLayout(new FlowLayout());
        add(new Button("OK"));
        add(new Button("Cancel"));
        setVisible(true);
    }
    public static void main(String[] args) {
        new FrameTest();
    }
}

Closing the Window Properly

By default clicking the close button does nothing. Implement WindowAdapter:

addWindowListener(new WindowAdapter() {
    public void windowClosing(WindowEvent e) {
        System.exit(0);
    }
});

Key Points

• Extend Frame (or use a Frame object) for a top-level window.
• Always call setVisible(true) after setting size and components.
• Add a WindowListener so the window can actually close.