table.java

Java程序设计技巧与开发实例附书源代码。

import java.awt.*;
import java.awt.event.*;

public class Table
        extends Frame
        implements ActionListener {
    private Button quit = new Button("Quit");
    private Button start = new Button("Start");
    private Button stop = new Button("Stop");
    private Marble marbles[] = new Marble[20];

    public Table() {
        super("Table with Marbles");
        setLayout(new FlowLayout());
        add(quit);
        quit.addActionListener(this);
        add(start);
        start.addActionListener(this);
        add(stop);
        stop.addActionListener(this);
        validate();
        setSize(300, 300);
        setVisible(true);
        for (int i = 0; i < marbles.length; i++) {
            int x = (int) (getSize().width * Math.random());
            int y = (int) (getSize().height * Math.random());
            marbles[i] = new Marble(this, x, y);
        }
    }

    public void actionPerformed(ActionEvent ae) {
        if (ae.getSource() == stop) {
            for (int i = 0; i < marbles.length; i++) {
                marbles[i].halt();
            }
        }
        if (ae.getSource() == start) {
            for (int i = 0; i < marbles.length; i++) {
                marbles[i].halt();
                marbles[i] = new Marble(this, marbles[i].x, marbles[i].y);
            }
        }
        if (ae.getSource() == quit) {
            System.exit(0);
        }
    }

    public void paint(Graphics g) {
        /* still to do */
        for (int i = 0; i < marbles.length; i++) {
            if (marbles[i] != null) {
                marbles[i].draw(g);

            }
        }
    }

    public static void main(String args[]) {
        Table table = new Table();
    }
}