Creation of a Frame

Note: A Container can contain other Components and other Containers(since Container is a sub-class of Component anyhow).

Thus an application starts off like this...

import java.awt.*;

public class MyApp extends Frame
{
	// "final" variables are constants
	static final int H_SIZE = 300;
	static final int V_SIZE = 200;

	public MyApp()
	{
		// Calls the parent constructor 
		// Frame(string title)
		// Equivalent to setTitle("My First Application")
		super("My First Application");

		pack();
		resize(H_SIZE, V_SIZE);
		show();
	}

	public static void main(String args[])
	{
		new MyApp();
	}
}

new MyApp("Hello World");
new MyApp(300, 200, "My First App");

public MyApp(String title){}
public MyApp(int x, int y, String title){}

show() is required because by default, AWT Containers are created hidden and must be made visible. Pack() is used here to properly adjust Components such as Buttons, Lists, etc. to their correct sizes.

Note: static void main(String args[]) is considered a class method, not an instance method. It really does not depend on an instance of MyApp and does not belong to it.

This is the result of the above code under Win95.

It has the following attributes:

• 300 x 200 Frame
• No menubar
• No Components
• Title bar with "My first Application"
• Default colored background
• Default layout
• Blank background

1. Change the font to a plain 12pt Times Roman font.
2. Set the background to white and foreground to black
3. Set the layout for this Container to be BorderLayout(see Introduction to the AWT and Panels and Layouts)

setFont(new Font("TimesRoman", Font.PLAIN, 12));
setBackground(Color.white);
setForeground(Color.black);
setLayout(new BorderLayout());

public void paint(Graphics g)
{
	// 24 pt red font used here
	g.setFont(new Font("TimesRoman", Font.BOLD, 24));
	g.setColor(Color.red);
	g.drawString(getTitle(), 30, 50);
}

Panel p = new Panel();
p.add(new Button("Ok"));
p.add(new Button("Cancel"));
add("South", p);

add(Component c)
add(String s, Component c)

add("South", new Button("Ok"));
add("South", new Button("Cancel"));

Do not worry if some of the material is flying over your head, I will explain in detail later. First we get our feet wet... very wet!

This should be the final result.

If you run the code above, you'll realize whenever you try to close the Window, nothing happens? Why?

You haven't handled the Event.WINDOW_DESTROY(static variable) message and properly exited.
So create an event handler for Event.WINDOW_DESTROY in handleEvent(Event evt).

public boolean handleEvent(Event evt)
{
	// Return false if we want the system to also process
	// the message, otherwise return true to say we're done
	// with the message
	switch(evt.id)
	{
		// Event.WINDOW_DESTROY documentation
		// can be found in the Event classes
		case Event.WINDOW_DESTROY:
		{
			System.exit(0);
			return true;
		}
		default:
	}		return super.handleEvent(evt);
}