KeyListener 和 jframe 的问题

Question

我在俄罗斯方块游戏中遇到 JFrame 和 KeyListerner 问题。我有两个框架 - 第一个带有“开始”按钮，第二个带有“板”。在第二帧中，我想从键盘控制形状，但是当我单击开始时我无法做到这一点。当我禁用第一帧时 - 一切都很好。我知道我必须专注于第二帧，我尝试这样做，但没有效果。有人可以帮助我吗？ 第一帧：

package tetris;

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;


public class Tetris implements ActionListener {
public Tetris() {
initComponents();
}
Component contentPane;
JLabel statusbar  = new JLabel(" 0"); 
JLabel name  = new JLabel("Tetris"); 
JButton startbut = new JButton("Start");
JFrame window = new JFrame();
JPanel panelStart = new JPanel();
JPanel game = new JPanel();
int nameSize=24;
Font fontName = new Font("Dialog", Font.BOLD, nameSize);
BorderLayout borderLayout = new BorderLayout();
Board board = new Board(this);

public void initComponents() {
    window.setBounds(500,200,200,400);
    window.setTitle("Tetris");
    window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    window.setVisible(true);

    window.add(panelStart);
    window.add(game);
    panelStart.setLayout (null);
    panelStart.setVisible(true);
    window.setContentPane(panelStart);

    name.setSize(70,25);
    name.setLocation(53,10);
    name.setFont(fontName);
    panelStart.add(name);
    startbut.setSize(70,25);
    startbut.setLocation(50,80);
    panelStart.add(startbut);
    startbut.addActionListener(this);
  }

public void initGame() {

    game.setLayout (borderLayout);
    panelStart.setVisible(false);
    window.remove(panelStart);

    game.setVisible(true);
    window.setContentPane(game);




    game.setFocusable(true);
    statusbar = new JLabel(" 0");
   game.add(statusbar, BorderLayout.SOUTH);
     game.add(board);
   board.start();

 }
 public JLabel getStatusBar() {
   return statusbar;
 }
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
if(e.getSource() == startbut)
{
    initGame();

}
}


}

板代码：

package tetris;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;


import tetris.Shape.Tetrominoes;


public class Board extends JPanel implements ActionListener      {


    final int BoardWidth = 10;
    final int BoardHeight = 22;

    Timer timer;
    boolean isFallingFinished = false;
    boolean isStarted = false;
    boolean isPaused = false;
    int numLinesRemoved = 0;
    int curX = 0;
    int curY = 0;
    JLabel statusbar;
    Shape curPiece;
    Tetrominoes[] board;



    public Board(Tetris parent) {


    //   setFocusable(true);
       curPiece = new Shape();
       timer = new Timer(400, this);
       timer.start(); 

       statusbar =  parent.getStatusBar();
       board = new Tetrominoes[BoardWidth * BoardHeight];
       KeyListener keyListener = new TAdapter();
       addKeyListener(keyListener);
       repaint();
       clearBoard();  

    }

    public void actionPerformed(ActionEvent e) {
        if (isFallingFinished) {
            isFallingFinished = false;
            newPiece();
        } else {
            oneLineDown();
        }
    }


    int squareWidth() { return (int) getSize().getWidth() / BoardWidth; }
    int squareHeight() { return (int) getSize().getHeight() / BoardHeight; }
    Tetrominoes shapeAt(int x, int y) { return board[(y * BoardWidth) + x]; }


    public void start()
    {
        if (isPaused)
            return;

        isStarted = true;
        isFallingFinished = false;
        numLinesRemoved = 0;
        clearBoard();

        newPiece();
        timer.start();
    }

    private void pause()
    {
        if (!isStarted)
            return;

        isPaused = !isPaused;
        if (isPaused) {
            timer.stop();
            statusbar.setText("paused");
        } else {
            timer.start();
            statusbar.setText(String.valueOf(numLinesRemoved));
        }
        repaint();
    }

    public void paint(Graphics g)
    { 
        super.paint(g);

        Dimension size = getSize();
        int boardTop = (int) size.getHeight() - BoardHeight * squareHeight();


        for (int i = 0; i < BoardHeight; ++i) {
            for (int j = 0; j < BoardWidth; ++j) {
                Tetrominoes shape = shapeAt(j, BoardHeight - i - 1);
                if (shape != Tetrominoes.NoShape)
                    drawSquare(g, 0 + j * squareWidth(),
                               boardTop + i * squareHeight(), shape);
            }
        }

        if (curPiece.getShape() != Tetrominoes.NoShape) {
            for (int i = 0; i < 4; ++i) {
                int x = curX + curPiece.x(i);
                int y = curY - curPiece.y(i);
                drawSquare(g, 0 + x * squareWidth(),
                           boardTop + (BoardHeight - y - 1) * squareHeight(),
                           curPiece.getShape());
            }
        }
    }

    private void dropDown()
    {
        int newY = curY;
        while (newY > 0) {
            if (!tryMove(curPiece, curX, newY - 1))
                break;
            --newY;
        }
        pieceDropped();
    }

    private void oneLineDown()
    {
        if (!tryMove(curPiece, curX, curY - 1))
            pieceDropped();
    }


    private void clearBoard()
    {
        for (int i = 0; i < BoardHeight * BoardWidth; ++i)
            board[i] = Tetrominoes.NoShape;
    }

    private void pieceDropped()
    {
        for (int i = 0; i < 4; ++i) {
            int x = curX + curPiece.x(i);
            int y = curY - curPiece.y(i);
            board[(y * BoardWidth) + x] = curPiece.getShape();
        }

        removeFullLines();

        if (!isFallingFinished)
            newPiece();
    }

    private void newPiece()
    {
        curPiece.setRandomShape();
        curX = BoardWidth / 2 + 1;
        curY = BoardHeight - 1 + curPiece.minY();

        if (!tryMove(curPiece, curX, curY)) {
            curPiece.setShape(Tetrominoes.NoShape);
            timer.stop();
            isStarted = false;
            statusbar.setText("game over");
        }
    }

    private boolean tryMove(Shape newPiece, int newX, int newY)
    {
        for (int i = 0; i < 4; ++i) {
            int x = newX + newPiece.x(i);
            int y = newY - newPiece.y(i);
            if (x < 0 || x >= BoardWidth || y < 0 || y >= BoardHeight)
                return false;
            if (shapeAt(x, y) != Tetrominoes.NoShape)
                return false;
        }

        curPiece = newPiece;
        curX = newX;
        curY = newY;
        repaint();
        return true;
    }

    private void removeFullLines()
    {
        int numFullLines = 0;

        for (int i = BoardHeight - 1; i >= 0; --i) {
            boolean lineIsFull = true;

            for (int j = 0; j < BoardWidth; ++j) {
                if (shapeAt(j, i) == Tetrominoes.NoShape) {
                    lineIsFull = false;
                    break;
                }
            }

            if (lineIsFull) {
                ++numFullLines;
                for (int k = i; k < BoardHeight - 1; ++k) {
                    for (int j = 0; j < BoardWidth; ++j)
                         board[(k * BoardWidth) + j] = shapeAt(j, k + 1);
                }
            }
        }

        if (numFullLines > 0) {
            numLinesRemoved += numFullLines;
            statusbar.setText(String.valueOf(numLinesRemoved));
            isFallingFinished = true;
            curPiece.setShape(Tetrominoes.NoShape);
            repaint();
        }
     }

    private void drawSquare(Graphics g, int x, int y, Tetrominoes shape)
    {
        Color colors[] = { new Color(0, 0, 0), new Color(204, 102, 102), 
            new Color(102, 204, 102), new Color(102, 102, 204), 
            new Color(204, 204, 102), new Color(204, 102, 204), 
            new Color(102, 204, 204), new Color(218, 170, 0)
        };


        Color color = colors[shape.ordinal()];

        g.setColor(color);
        g.fillRect(x + 1, y + 1, squareWidth() - 2, squareHeight() - 2);

        g.setColor(color.brighter());
        g.drawLine(x, y + squareHeight() - 1, x, y);
        g.drawLine(x, y, x + squareWidth() - 1, y);

        g.setColor(color.darker());
        g.drawLine(x + 1, y + squareHeight() - 1,
                         x + squareWidth() - 1, y + squareHeight() - 1);
        g.drawLine(x + squareWidth() - 1, y + squareHeight() - 1,
                         x + squareWidth() - 1, y + 1);

    }
    public boolean isFocusable() {
        return true;
    }
  public class TAdapter implements KeyListener  {
          public void keyTyped(KeyEvent e) {
          }
         public void keyPressed(KeyEvent e) {
             if (!isStarted || curPiece.getShape() == Tetrominoes.NoShape) {  
                 return;
             }

             int keycode = e.getKeyCode();

             if (keycode == 'p' || keycode == 'P') {
                 pause();
                 return;
             }

             if (isPaused)
                 return;

             switch (keycode) {
             case KeyEvent.VK_LEFT:
                 tryMove(curPiece, curX - 1, curY);
                 break;
             case KeyEvent.VK_RIGHT:
                 tryMove(curPiece, curX + 1, curY);
                 break;
             case KeyEvent.VK_DOWN:
                 tryMove(curPiece.rotateRight(), curX, curY);
                 break;
             case KeyEvent.VK_UP:
                 tryMove(curPiece.rotateLeft(), curX, curY);
                 break;
             case KeyEvent.VK_SPACE:
                 dropDown();
                 break;
             case 'd':
                 oneLineDown();
                 break;
             case 'D':
                 oneLineDown();
                 break;
             }

         }
        @Override
        public void keyReleased(KeyEvent arg0) {
            // TODO Auto-generated method stub

        }
     }
}

Answer 1

你的代码太大了，我无法深入研究，但你想做的事情是可能的。

不管怎样，我建议您移动到一个框架，并可能使用 CardLayout 或其他 GUI 项来隐藏和显示组件，因为让用户在游戏开始时更改屏幕是一种奇怪的 UI。将所有内容都集中在一个框架中会更加用户友好。这可能会解决您当前的问题。

Answer 2

同样，代码太大，无法挖掘。但是，如果您在设置焦点时遇到问题，请尝试 frame.requestFocus();

Answer 3

首先，想要获取焦点的 JPanel 必须是可聚焦的或焦点可遍历的。
您应该考虑重写 isFocusTraversable 以返回 true。

在您的面板类中：

@Override
public boolean isFocusTraversable()
{
  return true;
}//met

这意味着您的组件可以拥有焦点。

其次，如果您希望您的 jpanel* 实际上拥有焦点*，您可以调用他的方法，

panel.requestFocus();

您应该在游戏开始时、在 pack/setVisible( true ); 之后执行此操作。在每个动作监听器的末尾，这将使其失去焦点（通常是按钮的动作监听器）。

问候，
史蒂芬

Answer 4

您应该使用按键绑定，而不是使用KeyListener。

Answer 5

keyListener 在 Frame 中无法为我工作。后来我发现问题是我的关键控件转到了我在框架中添加的按钮。当我删除按钮时，按键控件返回到框架并且 keyEvents 正在工作。
但即使将按钮保留在框架中，我也没有找到使用 keyEvents 的方法！