我正在使用swing创建一个战舰式游戏。我在一个面板中绘制图像并显示正常，但是当我在不同的面板中绘制更多图像时，它会删除第一个面板中的大部分（如果不是全部）图像并保持第二个面板中的图像完好无损。如何在面板中绘制后保持图像不会消失。
我一直在网上寻找答案大约一个星期左右，并且什么都没有......
public class GameBoard extends JPanel{
Graphics g0;
public void paintComponent(Graphics g1) {
g0 = this.getGraphics();
// fill with the color you want
int wide = 275;
int tall = 275;
// go into Graphics2D for all the fine art, more options
// optional, here I just get variable Stroke sizes
Graphics2D g2 = (Graphics2D) g1;
g2.setColor(Color.black);
g2.setStroke(new BasicStroke(1));
Graphics2D g3 = (Graphics2D) g0;
g3.setColor(Color.black);
g3.setStroke(new BasicStroke(1));
// the verticals
for (int i = 0; i < 12*25; i+=25) {
g2.drawLine(i, 0, i, tall);
g3.drawLine(i, 0, i, tall);
}
// the horizontal
for (int i = 0; i < 12*25; i+=25) {
g2.drawLine(0, i, wide, i);
g3.drawLine(0, i, wide, i);
}
g0 = this.getGraphics();
}
public void paintComponent(Image i, int x, int y) {
g0.drawImage(i, x, y, null);
}
}
以上是我创建的第一个函数绘制网格的面板，第二个是在插入的cooridnates（x，y）中绘制和图像
public class Game {
static JFrame main = new JFrame();
static GameBoard panel = new GameBoard(), panel1 = new GameBoard();
static Container c = main.getContentPane();
static JLabel title = new JLabel("BattleShip!");
static int count = 0, x, y, j;
static String b;
static BufferedImage pB = null, aC = null, bS = null, deS = null, suB = null;
static BattleShips[] player = new BattleShips[5];
static BattleShips[] computer = new BattleShips[5];
static Graphics g;
public static void setup(){
player[0] = new BattleShips();
player[1] = new BattleShips();
player[2] = new BattleShips();
player[3] = new BattleShips();
player[4] = new BattleShips();
computer[0] = new BattleShips();
computer[1] = new BattleShips();
computer[2] = new BattleShips();
computer[3] = new BattleShips();
computer[4] = new BattleShips();
c.add(title);
c.add(panel);
c.add(panel1);
panel.setAlignmentY(Component.CENTER_ALIGNMENT);
panel.setAlignmentX(Component.CENTER_ALIGNMENT);
panel.setSize(276, 276);
panel1.setAlignmentY(Component.CENTER_ALIGNMENT);
panel1.setAlignmentX(Component.CENTER_ALIGNMENT);
panel1.setSize(276, 276);
title.setAlignmentY(Component.CENTER_ALIGNMENT);
title.setAlignmentX(Component.CENTER_ALIGNMENT);
main.setVisible(true);
main.setSize(new Dimension(291,630));
main.setResizable(true);
main.setLayout(new BoxLayout(c, BoxLayout.Y_AXIS));
main.setLocation(400, 15);
main.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Graphics g = panel.getGraphics(), g1 = panel1.getGraphics();
panel.paintComponent(g);
panel1.paintComponent(g1);
panel.setBorder(new EmptyBorder(0,0,25,0));
panel1.addMouseListener(new MouseListener(){
@Override
public void mouseClicked(MouseEvent e) {
String d = "H";
switch(count){
case 0:
player[0].Name = "patrolBoat";
player[0].x[0] = e.getX()-(e.getX()%25);
player[0].y[0] = (e.getY()-(e.getY()%25));
Object[] possibilities = {"H", "V"};
d = (String)JOptionPane.showInputDialog(
main,
"Place " + player[0].Name + " vertically or horizontally?",
"Customized Dialog",
JOptionPane.PLAIN_MESSAGE,
null,
possibilities,
"ham");
try {pB = ImageIO.read(new File("src/resources/"+player[0].Name+d+".png"));} catch (IOException e1) {}
panel1.paintComponent(pB,player[0].x[0],player[0].y[0]);
count++;
break;
case 1:
player[1].Name = "battleship";
player[1].x[0] = e.getX()-(e.getX()%25);
player[1].y[0] = (e.getY()-(e.getY()%25));
Object[] possibilities1 = {"H", "V"};
d = (String)JOptionPane.showInputDialog(
main,
"Place " + player[1].Name + " vertically or horizontally?",
"Customized Dialog",
JOptionPane.PLAIN_MESSAGE,
null,
possibilities1,
"ham");
try {bS = ImageIO.read(new File("src/resources/"+player[1].Name+d+".png"));} catch (IOException e1) {}
panel1.paintComponent(bS,player[1].x[0],player[1].y[0]);
count++;
break;
case 2:
player[2].Name = "aircraftCarrier";
player[2].x[0] = e.getX()-(e.getX()%25);
player[2].y[0] = (e.getY()-(e.getY()%25));
Object[] possibilities11 = {"H", "V"};
d = (String)JOptionPane.showInputDialog(
main,
"Place " + player[2].Name + " vertically or horizontally?",
"Customized Dialog",
JOptionPane.PLAIN_MESSAGE,
null,
possibilities11,
"ham");
try {aC = ImageIO.read(new File("src/resources/"+player[2].Name+d+".png"));} catch (IOException e3) {}
panel1.paintComponent(aC,player[2].x[0],player[2].y[0]);
count++;
break;
case 3:
player[3].Name = "destroyer";
player[3].x[0] = e.getX()-(e.getX()%25);
player[3].y[0] = (e.getY()-(e.getY()%25));
Object[] possibilities111 = {"H", "V"};
d = (String)JOptionPane.showInputDialog(
main,
"Place " + player[3].Name + " vertically or horizontally?",
"Customized Dialog",
JOptionPane.PLAIN_MESSAGE,
null,
possibilities111,
"ham");
try {deS = ImageIO.read(new File("src/resources/"+player[3].Name+d+".png"));} catch (IOException e2) {}
panel1.paintComponent(deS,player[3].x[0],player[3].y[0]);
count++;
break;
case 4:
player[4].Name = "submarine";
player[4].x[0] = e.getX()-(e.getX()%25);
player[4].y[0] = (e.getY()-(e.getY()%25));
Object[] possibilities1111 = {"H", "V"};
d = (String)JOptionPane.showInputDialog( main, "Place " + player[4].Name + " vertically or horizontally?", "Customized Dialog",JOptionPane.PLAIN_MESSAGE,null, possibilities1111, "ham");
try {suB = ImageIO.read(new File("src/resources/"+player[4].Name+d+".png"));} catch (IOException e1) {}
panel1.paintComponent(suB,player[4].x[0],player[4].y[0]);
count = 5;
break;
case 5:
try {setupComp();
count++;} catch (IOException e1) {}
}
}
@Override
public void mousePressed(MouseEvent e) {}
@Override
public void mouseReleased(MouseEvent e) {}
@Override
public void mouseEntered(MouseEvent e) {}
@Override
public void mouseExited(MouseEvent e) {}
});
}
static void setupComp() throws IOException{
b = "H";
g = panel.getGraphics();
////////DESTROYER
j = (int) (Math.random()*1);
computer[1].Name = "destroyer";
if(j == 0){
b = "H";
deS = ImageIO.read(new File("src/resources/"+computer[1].Name+b+".png"));}
else if(j == 1){
b = "V";
deS = ImageIO.read(new File("src/resources/"+computer[1].Name+b+".png"));}
computer[1].x[0] = ((int)(Math.random()*150));
computer[1].x[0] = computer[1].x[0]-computer[1].x[0]%25;
computer[1].y[0] = ((int)(Math.random()*150));
computer[1].y[0] = computer[1].y[0]-computer[1].y[0]%25;
///////END DESTROYER
//////PATROL BOAT
j = (int) (Math.random()*1);
computer[2].Name = "patrolBoat";
switch(j){
case 0:
b = "H";
pB = ImageIO.read(new File("src/resources/"+computer[2].Name+b+".png"));
case 1:
b = "V";
pB = ImageIO.read(new File("src/resources/"+computer[2].Name+b+".png"));
}
computer[2].x[0] = ((int)(Math.random()*225));
computer[2].x[0] = computer[2].x[0]-computer[2].x[0]%25;
computer[2].y[0] = ((int)(Math.random()*225));
computer[2].y[0] = computer[2].y[0]-computer[2].y[0]%25;
///////END PATROL BOAT
///////AIRCRAFT CARRIER
j = (int) (Math.random()*1);
computer[3].Name = "aircraftCarrier";
switch(j){
case 1:b = "H";
aC = ImageIO.read(new File("src/resources/"+computer[3].Name+b+".png"));
case 0:
b = "V";
aC = ImageIO.read(new File("src/resources/"+computer[3].Name+b+".png"));
}
computer[3].x[0] = ((int)(Math.random()*125));
computer[3].x[0] =computer[3].x[0]-computer[3].x[0]%25;
computer[3].y[0] = ((int)(Math.random()*125));
computer[3].y[0] = computer[3].y[0]-computer[3].y[0]%25;
///////END AIRCRAFT CARRIER
///////SUBMARINE
j = (int) (Math.random()*1);
computer[4].Name = "submarine";
switch(j){
case 0:b = "H";
suB = ImageIO.read(new File("src/resources/"+computer[4].Name+b+".png"));
case 1:
b = "V";
suB = ImageIO.read(new File("src/resources/"+computer[4].Name+b+".png"));
}
computer[4].x[0] = ((int)(Math.random()*200));
computer[4].x[0] = computer[4].x[0]-computer[4].x[0]%25;
computer[4].y[0] = ((int)(Math.random()*200));
computer[4].y[0] = computer[4].y[0]-computer[4].y[0]%25;
//END SUBMARINE
///////BATTLESHIP
j = (int) (Math.random()*1);
computer[0].Name = "battleship";
switch(j){
case 1:b = "H";
bS = ImageIO.read(new File("src/resources/"+computer[0].Name+b+".png"));
case 0:
b = "V";
bS = ImageIO.read(new File("src/resources/"+computer[0].Name+b+".png"));
}
computer[0].x[0] = ((int)(Math.random()*200));
computer[0].x[0] = computer[0].x[0]-computer[0].x[0]%25;
computer[0].x[0] = ((int)(Math.random()*200));
computer[0].x[0] = computer[0].y[0]-computer[0].y[0]%25;
///////END BATTLESHIP
System.out.println(computer[0].x[0]+","+computer[0].y[0]);
System.out.println(computer[1].x[0]+","+computer[1].y[0]);
System.out.println(computer[2].x[0]+","+computer[2].y[0]);
System.out.println(computer[3].x[0]+","+computer[3].y[0]);
System.out.println(computer[4].x[0]+","+computer[4].y[0]);
g.drawImage(bS, computer[0].x[0], computer[0].x[0], null);
g.drawImage(aC, computer[1].x[0], computer[1].x[0], null);
g.drawImage(pB, computer[2].x[0], computer[2].x[0], null);
g.drawImage(suB, computer[3].x[0], computer[3].x[0], null);
g.drawImage(deS, computer[4].x[0], computer[4].x[0], null); }}
答案 0 :(得分：5)
不要使用getGraphics()来获取Component的Graphics对象，而 never 直接调用paintComponent(...)。通过getGraphics()获取的Graphics对象只是暂时的，并且每当重新绘制时都不会持久存在。
直接在paintComponent方法（或由它调用的方法）中或间接在paintComponent中显示的BufferedImage中完成所有绘制。然后在需要显示已更改图像的组件上调用repaint()。这将告诉JVM它应该调用paintComponent(...)并传入一个有效的Graphics对象。
最重要的是，阅读图形教程，了解如何正确完成。这一切都可供您查看和学习 - 您的“大约1周左右”的搜索应该已经找到了这些内容，因为它们将成为Google搜索主题的首选。
修改
说完这一切之后，有些东西告诉我，你可以通过不搞乱任何这个绘图业务来做得更好，而是从你的图像创建ImageIcons然后在JLabel中显示它们。这是使用Java Swing显示图像的最简单方法。