我正在开发一个连接四游戏，当我点击屏幕时，我正试图让多个圆圈显示出来。现在，每次我点击一下，我刚画的圆就消失了。
感谢任何帮助。
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g; // create 2d object
g2d.setStroke(new BasicStroke(2)); // set thickness of line
// each box is 100 x 100
// draws the vertical lines
for (int i = 0; i < 8; i++) {
g2d.drawLine(140 + i * DISC_RADIUS, 30, 140 + i * DISC_RADIUS, 690);
}
// draws the horizontal lines
for (int i = 0; i < 7; i++) {
g2d.drawLine(140, 90 + i * DISC_RADIUS, 840, 90 + i * DISC_RADIUS);
}
// draws the circles
for (int i = 0; i < 6; i++) { // new vertical row of circles
for (int j = 0; j < 7; j++) { // new horizontal row of circles
g2d.drawOval(140 + j * DISC_RADIUS, 90 + i * DISC_RADIUS, DISC_RADIUS, DISC_RADIUS);
}
}
// if at the start of the game, will not draw the counters
if (start == true) {
// draws blue counter
g2d.drawOval(20, 90, DISC_RADIUS, DISC_RADIUS);
g2d.setColor(Color.BLUE); // sets colour to blue
g2d.fillOval(20, 90, DISC_RADIUS, DISC_RADIUS); // draws the circle
// draws red counter
g2d.setColor(Color.BLACK);
g2d.drawOval(875, 90, DISC_RADIUS, DISC_RADIUS);
g2d.setColor(Color.RED); // sets the colour to red
g2d.fillOval(875, 90, DISC_RADIUS, DISC_RADIUS); // draws the circle
}
//print on the screen who's turn it is
// draws blue counter stand;
g2d.setStroke(new BasicStroke(4)); // sets the line width
g2d.setColor(Color.BLACK); // changes the outline colour to black
g2d.drawPolygon(poly1); // draw the outline
g2d.setColor(Color.GRAY); // changes the fill colour to grey
g2d.fillPolygon(poly1); // draws the filling
// draws bred counter stand;
g2d.setColor(Color.BLACK); // changes the outline colour to black
g2d.drawPolygon(poly2); // draws the outline
g2d.setColor(Color.GRAY); // changes the fill colour to grey
g2d.fillPolygon(poly2); // draws the filling
repaint();
if(Player.getPlayer() == "Blue"){
g2d.setColor(Color.BLACK);
if(draw == true){
g2d.drawString("Blue's Turn", 40, 300);
g2d.drawOval(xPos, yPos, DISC_RADIUS, DISC_RADIUS);
g2d.setColor(Color.BLUE); // sets colour to blue
g2d.fillOval(xPos, yPos, DISC_RADIUS, DISC_RADIUS); // draws the circle
}
}
if(Player.getPlayer() == "Red"){
g2d.drawString("Red's Turn", 900, 300);
if(draw == true){
g2d.drawOval(xPos, yPos, DISC_RADIUS, DISC_RADIUS);
g2d.setColor(Color.RED); // sets colour to blue
g2d.fillOval(xPos, yPos, DISC_RADIUS, DISC_RADIUS); // draws the circle
}
}
}
}
答案 0 :(得分：1)
绘画是破坏性的，也就是说，每次调用paintComponent时，都需要从头开始重新绘制组件的整个状态。
你应该做的是创建某种模型，以维护哪个玩家选择了哪个单元格的信息。
例如，您可以使用String的2D数组，其中null表示无身体，Red表示红色玩家，Blue表示蓝色播放器。然后，您将使用一个简单的复合循环来遍历数组并相应地绘制UI ...
现在，if(Player.getPlayer() == "Blue"){不是String比较在Java中的工作原理，您应该使用更像if("Blue".equals(Player.getPlayer())){的内容。
不要直接或间接地在任何绘制方法中更新或修改UI的状态，这可能会设置一个无限循环的绘制请求，这将占用您的CPU周期......
答案 1 :(得分：0)
一个人不应该在repaint()方法中调用paintComponent()，因为repaint()会以某种方式调用paintComponent()，从而导致递归调用。
此外，当调用repaint()时，整个JComponent实际上是从初始状态绘制的。为了让您可以在JPanel/JComponent上绘制圆圈，可以使用Collection/Array来跟踪已绘制的内容。因此代码可以迭代此Collection/Array来重绘以前绘制的所有圆圈和要绘制的新圆圈。
以下是小样本示例：
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.*;
public class CircleExample {
private static final int GAP = 5;
private JPanel drawingBoard;
private void displayGUI() {
JFrame frame = new JFrame("Circle Drawing Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setLayout(new BorderLayout(GAP, GAP));
contentPane.setBorder(BorderFactory.createEmptyBorder(GAP, GAP, GAP, GAP));
drawingBoard = new DrawingBoard();
contentPane.add(drawingBoard);
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
Runnable runnable = new Runnable() {
@Override
public void run() {
new CircleExample().displayGUI();
}
};
EventQueue.invokeLater(runnable);
}
}
class DrawingBoard extends JPanel {
private static final int WIDTH = 300;
private static final int HEIGHT = 350;
private List<MyCircle> circles;
private Random random;
private MouseAdapter mouseAdapter = new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent me) {
System.out.println("Mouse Clicked");
int x = me.getX();
int y = me.getY();
circles.add(new MyCircle(x, y, getRandomColour()));
DrawingBoard.this.repaint();
}
};
public DrawingBoard() {
super();
circles = new ArrayList<MyCircle> ();
random = new Random();
setOpaque(true);
addMouseListener(mouseAdapter);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(WIDTH, HEIGHT);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (MyCircle circle : circles) {
circle.drawCircle(g);
}
}
private Color getRandomColour() {
return new Color(random.nextFloat(), random.nextFloat(),
random.nextFloat(), random.nextFloat());
}
}
class MyCircle {
private int x;
private int y;
private Color backgroundColour;
private static final int RADIUS = 20;
public MyCircle(int x, int y, Color backgroundColour) {
this.x = x;
this.y = y;
this.backgroundColour = backgroundColour;
}
public void drawCircle(Graphics g) {
g.setColor(backgroundColour);
g.fillOval(x, y, RADIUS, RADIUS);
}
}