ballcontrol.java

JAVA程序设计导论那本书上的一些源代码. 在学那本书的下来的

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

public class BallControl extends JPanel
    implements ActionListener, AdjustmentListener {
  private Ball ball = new Ball();
  private JButton jbtSuspend = new JButton("Suspend");
  private JButton jbtResume = new JButton("Resume");
  private JScrollBar jsbDelay = new JScrollBar();

  public BallControl() {
    // Group buttons in a panel
    JPanel panel = new JPanel();
    panel.add(jbtSuspend);
    panel.add(jbtResume);

    // Add ball and buttons to the panel
    ball.setBorder(new javax.swing.border.LineBorder(Color.red));
    jsbDelay.setOrientation(JScrollBar.HORIZONTAL);
    ball.setDelay(jsbDelay.getMaximum());
    setLayout(new BorderLayout());
    add(jsbDelay, BorderLayout.NORTH);
    add(ball, BorderLayout.CENTER);
    add(panel, BorderLayout.SOUTH);

    // Register listeners
    jbtSuspend.addActionListener(this);
    jbtResume.addActionListener(this);
    jsbDelay.addAdjustmentListener(this);
  }

  public void actionPerformed(ActionEvent e) {
    if (e.getSource() == jbtSuspend)
      ball.suspend();
    else if (e.getSource() == jbtResume)
      ball.resume();
  }

  public void adjustmentValueChanged(AdjustmentEvent e) {
    ball.setDelay(jsbDelay.getMaximum() - e.getValue());
  }
}