我正在写一个国际象棋程序，我正在处理促进一个棋子的问题。当一个pawn达到最终排名时，应该弹出一个新的jframe，允许用户选择他想要将pawn提升到的peice。问题是，当我从main方法创建这个框架时，它显示得很好，但是当我在我的mouselistener代码中创建它时，它会在屏幕上显示它背后的确切内容，我不知道为什么。这是我的相关代码：
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
public class Example extends JFrame {
private SquarePanel[][] squares;
private Colors colors;
public Example () {
super();
colors = new Colors();
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container con = this.getContentPane();
setSize(800,800);
setLocation(0,0);
con.setLayout(new GridLayout(8,8));
SquarePanel pane = null;
SquarePanel lastpanel = null;
squares = new SquarePanel[8][8];
int color = colors.WHITE;
for(int i = 7; i >= 0; --i) {
if(color == colors.WHITE)
color = colors.BLACK;
else
color = colors.WHITE;
for(int j = 0; j <= 7; ++j) {
if(color == colors.WHITE)
color = colors.BLACK;
else
color = colors.WHITE;
lastpanel = new SquarePanel(color,j,i);
pane = lastpanel;
con.add(pane);
squares[j][i] = pane;
}
}
for(int i = 0; i < 8; ++i) {
for(int j = 0; j < 8; ++j) {
squares[j][i].setResident("pawn");
//System.out.println(squares[j][i].getResident());
//squares[j][i].repaint();
}
}
MouseListener listener = new MoveListener(this, squares);
for(int i = 0; i < 8; ++i)
for(int j = 0; j < 8; ++j)
squares[i][j].addMouseListener(listener);
setVisible(true);
PromotionFrame pf = new PromotionFrame(this, 1);
String p = null;
while(p == null) {
p = pf.getPiece();
}
pf.dispose();
}
public class SquarePanel extends JPanel {
private ImageIcon content;
private int x;
private int y;
private int color;
private String resident;
private Colors colors;
public SquarePanel(int color, int x, int y) {
content = null;
resident = null;
this.color = color;
colors = new Colors();
this.x = x;
this.y = y;
Border blackline = BorderFactory.createLineBorder(Color.black);
setBorder(blackline);
this.setLayout(new GridBagLayout());
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
int width = getWidth();
int height = getHeight();
if(color == colors.WHITE)
g.setColor(Color.white);
else
g.setColor(Color.green);
g.fillRect(0, 0, width, height);
g.setColor(Color.black);
//System.out.println("here");
}
public String getResident() {
return resident;
}
public void setResident(String p) {
resident = p;
if(p == null)
removeAll();
else
add(new JLabel(p));
}
public int getXCoordinate() {
return x;
}
public int getYCoordinate() {
return y;
}
}
private class Colors {
public int BLACK = 0;
public int WHITE = 1;
}
public class MoveListener implements MouseListener {
private int first_click;
private SquarePanel first_source;
private JFrame frame;
private int turn;
private SquarePanel[][] squares;
public MoveListener(JFrame f, SquarePanel[][] s) {
first_click = 0;
this.frame = f;
turn = colors.WHITE;
squares = s;
}
/* Empty method definition. */
public void mousePressed(MouseEvent e) {
SquarePanel p = (SquarePanel)e.getSource();
ImageIcon content = null;
if(first_click == 0) {
first_source = p;
++first_click;
p.setBorder(BorderFactory.createLineBorder(Color.cyan,4));
}
else {
first_click = 0;
first_source.setBorder(BorderFactory.createLineBorder(Color.black));
//System.out.println(turn == colors.WHITE ? "White" : "Black");
if(p.getResident().equals("pawn") && (p.getYCoordinate() == 7 || p.getYCoordinate() == 0)) {
PromotionFrame pframe = new PromotionFrame(frame, colors.WHITE);
String piece;
do {
piece = pframe.getPiece();
}
while(piece == null);
System.out.println(piece);
pframe.dispose();
p.setResident(piece);
}
}
}
/* Empty method definition. */
public void mouseReleased(MouseEvent e) {
}
/* Empty method definition. */
public void mouseEntered(MouseEvent e) {
}
/* Empty method definition. */
public void mouseExited(MouseEvent e) {
}
public void mouseClicked(MouseEvent e) {
}
}
public class PromotionFrame extends JFrame implements MouseListener {
private JFrame master;
private String piece;
public PromotionFrame(JFrame master, int color) {
super();
this.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
Container con = this.getContentPane();
setSize(400,200);
this.master = master;
setLocation(master.getX()+master.getWidth()/2-200,master.getY()+master.getHeight()/2-100);
setLocation(0,0);
con.setLayout(new GridLayout(1,4));
ImageIcon imgicon1;
Image img1;
Image newimg;
ImageIcon img;
ImageLabel label;
piece = null;
label = new ImageLabel("queen");
label.addMouseListener(this);
con.add(label);
label = new ImageLabel("rook");
label.addMouseListener(this);
con.add(label);
label = new ImageLabel("bishop");
label.addMouseListener(this);
con.add(label);
label = new ImageLabel("knight");
label.addMouseListener(this);
con.add(label);
this.show();
}
public String getPiece() {
return piece;
}
/* Empty method definition. */
public void mousePressed(MouseEvent e) {
ImageLabel label = (ImageLabel)e.getSource();
piece = label.getPiece();
}
/* Empty method definition. */
public void mouseReleased(MouseEvent e) {
}
/* Empty method definition. */
public void mouseEntered(MouseEvent e) {
}
/* Empty method definition. */
public void mouseExited(MouseEvent e) {
}
public void mouseClicked(MouseEvent e) {
}
private class ImageLabel extends JLabel {
private String piece;
ImageLabel(String piece) {
super(piece);
this.piece = piece;
}
public String getPiece() {
return piece;
}
}
}
public static void main(String[] args) {
new Example();
}
}
答案 0 :(得分：1)
1）改变主要
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
Example example = new Example();
}
});
}
2）
你的弹出窗口PromotionFrame可能很容易冻结，因为在MouseListener内你在每个MouseEvents上创建了它，小心地，MouseListener生成了不可信的Events，然后同样amout of PromotionFrame_s
A）
class PromotionFrame extends JDialog implements MouseListener {
b）
this.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
c）中
你的意思是什么，这个代码阻止一个JLabel有四个不同的定义，然后last对当前代码有效
label = new ImageLabel("queen");
label.addMouseListener(this);
con.add(label);
label = new ImageLabel("rook");
label.addMouseListener(this);
con.add(label);
label = new ImageLabel("bishop");
label.addMouseListener(this);
con.add(label);
label = new ImageLabel("knight");
label.addMouseListener(this);
con.add(label);
d）
this.show();
到
this.setVisible(true);
e）仅创建一次PromotionFrame代码，将其重新用于其他操作或事件
3）请再次阅读LayoutManagers的工作原理