sharkcontrols.java

Java程序设计技巧与开发实例附书源代码。

import java.net.*;
import java.awt.event.*;
import java.awt.GridLayout;
import javax.swing.*;

public class SharkControls
        extends JFrame
        implements ActionListener
{
    private String icons[] =
            {
            "stop.gif", "up.gif", "rise.gif",
            "left.gif", "swan.gif", "right.gif",
            "start.gif", "down.gif", "dive.gif"};
    private String tips[] =
            {
            "Stop game", "Shark up", "Shark rises",
            "Shark left", "Help", "Shark right",
            "Start game", "Shark down", "Shark dives"};
    private SharkAttack applet = null;
    private Shark shark = null;
    private JButton buttons[] = new JButton[9];
    public SharkControls(SharkAttack _applet, Shark _shark)
    {
        super("Shark Controls");
        applet = _applet;
        shark = _shark;
        JPanel buttonPanel = new JPanel(new GridLayout(3, 3));
        try
        {
            for (int i = 0; i < buttons.length; i++)
            {
                URL url = new URL(applet.getCodeBase(), "Images/" + icons[i]);
                buttons[i] = new JButton(new ImageIcon(url));
                buttons[i].addActionListener(this);
                buttons[i].setToolTipText(tips[i]);
                buttonPanel.add(buttons[i]);
            }
        }
        catch (MalformedURLException murle)
        {
            System.err.println("Error loading icons: " + murle);
        }
        getContentPane().add("Center",
                             new JPanelBox(buttonPanel, "Shark Controls"));
        setResizable(false);
        validate();
        pack();
    }

    public void actionPerformed(ActionEvent ae)
    {
        if (ae.getSource() == buttons[0])
        {
            applet.stop();
        }
        else if (ae.getSource() == buttons[1])
        {
            shark.moveUp();
        }
        else if (ae.getSource() == buttons[2])
        {
            shark.rise();
        }
        else if (ae.getSource() == buttons[3])
        {
            shark.turnLeft();
        }
        else if (ae.getSource() == buttons[4])
        {
            showHelp();
        }
        else if (ae.getSource() == buttons[5])
        {
            shark.turnRight();
        }
        else if (ae.getSource() == buttons[6])
        {
            applet.start();
        }
        else if (ae.getSource() == buttons[7])
        {
            shark.moveDown();
        }
        else if (ae.getSource() == buttons[8])
        {
            shark.dive();
        }
    }

    private void showHelp()
    {
        JOptionPane.showMessageDialog(this,
                                      "Shark Attack\n(c) 2003\n",
                                      "Shark Attack",
                                      JOptionPane.INFORMATION_MESSAGE);
    }
}