我已经建立了一个俄罗斯方块游戏。现在我已经使用JPanel来显示内容和块（使用paintComponents（）方法）。
问题在于，每当我尝试从另一个JFrame调用tetris程序时，它根本就不会绘制。
我的俄罗斯方块主菜单的代码是：
import javax.swing.*;
import sun.audio.AudioPlayer;
import sun.audio.AudioStream;
import java.awt.*;
import java.awt.event.*;
import java.io.FileInputStream;
import java.io.InputStream;
@SuppressWarnings("serial")
public class Tetris_MainMenu extends JFrame implements ActionListener {
@SuppressWarnings("unused")
public static void main(String[] args) {
Tetris_MainMenu tmm = new Tetris_MainMenu();
playAudio("doak.wav");
}
JPanel logo = new JPanel();
JPanel buttonPanel = new JPanel(new GridLayout(4, 1));
JButton start = new JButton("START NEW GAME");
JButton help = new JButton("INSTRUCTIONS");
JButton about = new JButton("ABOUT THIS GAME");
JButton exit = new JButton("EXIT");
Tetris_MainMenu(){
setTitle("JAG's TETRIS");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocation(300, 100);
setSize(200, 400);
setEnabled(true);
setFocusable(true);
setVisible(true);
//adding a logo to the logo panel
//adding buttons to the buttonPanel
buttonPanel.add(start);
buttonPanel.add(help);
buttonPanel.add(about);
buttonPanel.add(exit);
//add panels to window
setLayout(new GridLayout(2, 1));
add(logo);
add(buttonPanel);
//make buttons listen to actions
start.addActionListener(this);
help.addActionListener(this);
about.addActionListener(this);
exit.addActionListener(this);
}
@SuppressWarnings("restriction")
public static void playAudio(String filename)
{
InputStream in = null;
AudioStream as = null;
try{
in = new FileInputStream(filename);
as = new AudioStream(in);
}
catch(Exception e){
System.out.println("Error!!!");
}
AudioPlayer.player.start(as);
}
@Override
public void actionPerformed(ActionEvent e) {
if(e.getSource() == start){
this.dispose();
MatrixBoard b = new MatrixBoard();
b.setRequestFocusEnabled(true);
}
else if(e.getSource() == help){
JOptionPane.showMessageDialog(null, "Controls:\n"
+ "LEFT and RIGHT ARROWS: For moving blocks left and right\n"
+ "DOWN ARROW: For dropping block immediately\n"
+ "SPACEBAR: For rotating block\n"
+ "e: To exit to main menu");
}
else if(e.getSource() == about){
JOptionPane.showMessageDialog(null, "Designed by: JAG."
+ "\nIf you want you can use it for your own purposes."
+ "\nBut give credit where it is due.");
}
else if(e.getSource() == exit){
int opt = JOptionPane.showConfirmDialog(null, "Are you sure?", "Confirm Exit", JOptionPane.YES_NO_OPTION);
if(opt == JOptionPane.YES_OPTION){
System.exit(0);
}
}
}
}
当调用MatrixBoard的构造函数时，俄罗斯方块游戏在新窗口中启动。但是在屏幕上看不到块。 MatrixBoard的代码是：
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import sun.audio.*;
@SuppressWarnings("serial")
public class MatrixBoard extends JPanel implements ActionListener{
int boardHeight = 20;
int boardWidth = 10;
int score = 0;
int curX = 0, curY = 0;
int squareWidth;
int squareHeight;
Timer timer;
int sleepTime = 300;
Shape curPiece;
Shape.Tetromino[][] board;
boolean isFallingFinished = false;
boolean isStarted = false;
boolean isPaused = false;
JFrame f;
@SuppressWarnings("unused")
public static void main(String [] args){
MatrixBoard b = new MatrixBoard();
}
public void update(Graphics g) {
Graphics offgc;
Image offscreen = null;
Dimension d = getSize();
// create the offscreen buffer and associated Graphics
offscreen = createImage(d.width, d.height);
offgc = offscreen.getGraphics();
// clear the exposed area
offgc.setColor(getBackground());
offgc.fillRect(0, 0, d.width, d.height);
offgc.setColor(getForeground());
// do normal redraw
paint(offgc);
// transfer offscreen to window
g.drawImage(offscreen, 0, 0, this);
}
@SuppressWarnings("restriction")
public static void playAudio(String filename)
{
InputStream in = null;
AudioStream as = null;
try{
in = new FileInputStream(filename);
as = new AudioStream(in);
}
catch(Exception e){
System.out.println("Error!!!");
}
AudioPlayer.player.start(as);
}
MatrixBoard(){
f = new JFrame("JAG's TETRIS");
f.setVisible(true);
f.setSize(205, 400);
f.setFocusable(true);
f.setBackground(Color.GREEN);
f.add(this);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(200, 400);
setVisible(true);
setFocusable(true);
requestFocusInWindow();
setBackground(Color.BLACK);
timer = new Timer(400, this);
timer.setInitialDelay(10);
squareWidth = (getWidth())/ boardWidth;
squareHeight = (getHeight()) / boardHeight;
curPiece = new Shape();
board = new Shape.Tetromino[boardWidth][boardHeight];
addKeyListener(new KeyHandler());
clearBoard();
timer.start();
JOptionPane.showMessageDialog(null, "Press Enter to Start!!!");
f.setEnabled(true);
f.setResizable(false);
//setEnabled(true);
start();
System.out.println("MatrixBoard() Success!");
}
public void clearBoard(){
for(int i = 0; i < boardWidth; ++i)
for(int j = 0; j < boardHeight; ++j)
board[i][j] = Shape.Tetromino.NoShape;
}
public void start()
{
if (isPaused)
return;
clearBoard();
timer.start();
timer = new Timer(400, this);
timer.setInitialDelay(100);
isStarted = true;
isFallingFinished = false;
score = 0;
repaint();
newPiece();
System.out.println("START SUCCESS!");
}
private void newPiece(){
if(!isStarted) return;
curPiece.generateShape();
curX = boardWidth / 2;
curY = 1;
if(!tryMove(curPiece, curX, curY)){
curPiece.selectPiece(Shape.Tetromino.NoShape);
isStarted = false;
JOptionPane.showMessageDialog(null, "Game Over! Score : " + score);
isStarted = false;
int opt = JOptionPane.showConfirmDialog(null, "Try Again?", "Again?", JOptionPane.YES_NO_OPTION);
if(opt == JOptionPane.YES_OPTION){
start();
}
else if (opt == JOptionPane.NO_OPTION){
System.exit(0);
}
//dispose();
System.exit(0);
//new Tetris();
return;
}
dropDown();
System.out.println("NEW PIECE SUCCESS!");
}
private boolean tryMove(Shape newPiece, int newX, int newY){
for(int i = 0; i < 4; i++){
int x = newX + newPiece.coords[i][0];
int y = newY + newPiece.coords[i][1];
if(x < 0 || x >= boardWidth || y < 0 || y >= boardHeight){
System.out.println("FALSE1");
return false;
}
if(board[x][y] != Shape.Tetromino.NoShape){
System.out.println("FALSE2");
return false;
}
}
curPiece = newPiece;
curX = newX;
curY = newY;
System.out.println("curX = " + curX + " curY = " + curY);
System.out.println("TRY MOVE SUCCESS!");
return true;
}
private void dropDown(){
int newY = curY;
sleepTime = 300;
System.out.println("newY = " + newY);
while(newY < boardHeight){
if(!tryMove(curPiece, curX, newY+1)){ break;}
++newY;
System.out.println("calling f.update()");
repaint();
System.out.println("called f.update()");
try {
Thread.sleep(sleepTime);
} catch (Exception e) {
e.printStackTrace();
}
}
pieceDropped();
System.out.println("DROPDOWN SUCCESS!");
}
private void pieceDropped(){
for(int i = 0; i < 4; i++){
int x = curX + curPiece.coords[i][0];
int y = curY + curPiece.coords[i][1];
board[x][y] = curPiece.retShape();
System.out.println("PIECE: at X = " + x + " Y = " + y + "is " + curPiece.retShape().ordinal());
}
removeFullLines();
if(!isFallingFinished) newPiece();
System.out.println("PIECE DROPPED SUCCESS!");
}
public void paintComponent(Graphics g){
System.out.println("PAINTED\n\n\n\n\nPAINTED!!!!");
super.paintComponent(g);
Dimension size = getSize();
int boardTop = (int) size.getHeight() - boardHeight * squareHeight;
System.out.println("PAINTED\n\n\n\n\nPAINTED!!!!");
for (int i = 0; i < boardWidth; ++i) {
for (int j = 0; j < boardHeight; ++j) {
Shape.Tetromino shape = board[i][j];
if (shape != Shape.Tetromino.NoShape)
drawSquare(g, i * squareWidth,
boardTop + j * squareHeight, shape);
}
}
if (curPiece.retShape() != Shape.Tetromino.NoShape) {
for (int i = 0; i < 4; ++i) {
int x = curX + curPiece.coords[i][0];
int y = curY + curPiece.coords[i][1];
drawSquare(g, x * squareWidth,
boardTop + (y - 1) * squareHeight,
curPiece.retShape());
}
}
}
private void drawSquare(Graphics g, int x, int y, Shape.Tetromino 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);
}
private void removeFullLines(){
int numLines = 0;
for(int i = 0; i < boardHeight; i++){
boolean isLineFull = true;
for(int j = 0; j < boardWidth; j++){
System.out.println("i = " + i + " j = " + j);
if(board[j][i] == Shape.Tetromino.NoShape){
System.out.println("Found No Shape here!");
isLineFull = false;
break;
}
}
System.out.println("IIIIIIIIS LINE : " + isLineFull);
if(isLineFull){
numLines++;
for(int k = i; k > 0; k--){
for(int j = 0; j < boardWidth; ++j){
board[j][k] = board[j][k-1];
}
}
}
}
if(numLines > 0){
score += numLines * numLines;
repaint();
newPiece();
}
}
class KeyHandler extends KeyAdapter{
public void keyPressed(KeyEvent e){
if(!isStarted || curPiece.retShape() == Shape.Tetromino.NoShape){
return;
}
int keyCode = e.getKeyCode();
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:
sleepTime = 10;
break;
case KeyEvent.VK_E:
int opt = JOptionPane.showConfirmDialog(null,"Are you sure?", "Exit", JOptionPane.YES_NO_OPTION);
if(opt == JOptionPane.YES_OPTION){
System.exit(0);
}
break;
case KeyEvent.VK_SPACE:
tryMove(curPiece.rotateLeft(), curX, curY);
break;
default:
break;
}
}
}
@Override
public void actionPerformed(ActionEvent e) {
if (isFallingFinished) {
isFallingFinished = false;
newPiece();
}
}
}
请帮忙。我怀疑问题是在重绘机制中，但我不确定。
答案 0 :(得分：3)
您的问题似乎是Swing线程问题，因为您似乎在Swing事件线程上调用了Thread.sleep(...)。这样做会锁定整个线程，冻结你的应用程序。不要这样做，而是使用Swing Timer。
顺便说一句，你不想覆盖Swing GUI的update()方法，因为它主要用于AWT GUI，除非你在中途改变应用程序的外观。
修改
你问：
我理解调用Thread.sleep（）是不可取的，最好使用定时器。但问题是当我单独运行MatrixBoard时，它运行得非常好。这里不涉及线程问题。请尽可能解释。
当你自己调用它时，主应用程序没有在Swing线程上运行（这不是应该做的事情 - 所有Swing应用程序应该在Swing事件线程上运行），所以你的代码似乎工作。一旦强制它在Swing事件线程上运行，它就会冻结。
所有Swing GUI都应使用SwingUtilities.invokeLater(new Runnable() {...});
修改2
观察更改此内容后会发生什么：
public static void main(String [] args){
MatrixBoard b = new MatrixBoard();
}
更合适的代码：
public static void main(String[] args){
SwingUtilities.invokeLater(new Runnable() {
public void run() {
MatrixBoard b = new MatrixBoard();
}
});
}
我敢打赌你的MatrixBoard不会冻结（虽然我还没有测试过）。