package els;
    /**
     * File: ControlPanel.java
     * User:隋国丞
     * Date: 2004.12.3
     * Describe: 俄罗斯方块的 Java 实现
     */
    import javax.swing.*;
    import javax.swing.border.Border;
    import javax.swing.border.EtchedBorder;
    import java.awt.*;
    import java.awt.event.*;
    /**
     * 控制面板类，继承自JPanel.
     * 上边安放预显窗口、等级、得分、控制按钮
     * 主要用来控制游戏进程。
     */
    class ControlPanel extends JPanel {
     private JTextField
     tfLevel = new JTextField("" + ErsBlocksGame.DEFAULT_LEVEL),
     tfScore = new JTextField("0");
     private JButton
     btPlay = new JButton("Play"),
     btPause = new JButton("Pause"),
     btStop = new JButton("Stop"),
     btTurnLevelUp = new JButton("Turn hard"),
     btTurnLevelDown = new JButton("Turn easy");
     private JPanel plTip = new JPanel(new BorderLayout());
     private TipPanel plTipBlock = new TipPanel();
     private JPanel plInfo = new JPanel(new GridLayout(4, 1));
     private JPanel plButton = new JPanel(new GridLayout(5, 1));
     private Timer timer;
     private ErsBlocksGame game;
     private Border border = new EtchedBorder(
     EtchedBorder.RAISED, Color.white, new Color(148, 145, 140));
     /**
     * 控制面板类的构造函数
     * @param game ErsBlocksGame, ErsBoxesGame类的一个实例引用，
     * 方便直接控制ErsBoxesGame类的行为。
     */
     public ControlPanel(final ErsBlocksGame game) {
     setLayout(new GridLayout(3, 1, 0, 4));
     this.game = game;
     plTip.add(new JLabel("Next block"), BorderLayout.NORTH);
     plTip.add(plTipBlock);
     plTip.setBorder(border);
     plInfo.add(new JLabel("Level"));
     plInfo.add(tfLevel);
     plInfo.add(new JLabel("Score"));
     plInfo.add(tfScore);
     plInfo.setBorder(border);
     tfLevel.setEditable(false);
     tfScore.setEditable(false);
     plButton.add(btPlay);
     plButton.add(btPause);
     plButton.add(btStop);
     plButton.add(btTurnLevelUp);
     plButton.add(btTurnLevelDown);
     plButton.setBorder(border);
     add(plTip);
     add(plInfo);
     add(plButton);
     addKeyListener(new ControlKeyListener());
     btPlay.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent ae) {
     game.playGame();
     }
     });
     btPause.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent ae) {
     if (btPause.getText().equals(new String("Pause"))) {
     game.pauseGame();
     } else {
     game.resumeGame();
     }
     }
     });
     btStop.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent ae) {
     game.stopGame();
     }
     });
     btTurnLevelUp.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent ae) {
     try {
     int level = Integer.parseInt(tfLevel.getText());
     if (level < ErsBlocksGame.MAX_LEVEL)
     tfLevel.setText("" + (level + 1));
     } catch (NumberFormatException e) {
     }
     requestFocus();
     }
     });
     btTurnLevelDown.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent ae) {
     try {
     int level = Integer.parseInt(tfLevel.getText());
     if (level > 1)
     tfLevel.setText("" + (level - 1));
     } catch (NumberFor