以下是我的任务规范：
编写一个名为Die的类，它扩展了JPanel。这一类的物体，代表一个标准的六面模具，应该在面板上绘制一个自己的表示，画出模具单面的自上而下的视图就足以显示滚动的“当前”数字。该类还应提供方法updateVal（int i）。接受介于1和6之间的int，然后更新显示以显示新值。
我已完成所有操作，直到最后一次updateVal（int i）方法，并且遇到此问题并使其覆盖我在paintComponent（Graphics g）中分配给roll的随机值。基本上这个方法应该能够指定程序在启动时应该显示的面。
package weekThree;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.util.*;
@SuppressWarnings("serial")
public class Die extends JPanel {
static Random rand = new Random();
private Color circleColor = Color.BLACK;
private int circX = 75;
private int circY = circX;
private int circW = 75;
private int circH = circW;
public Die() {
addMouseListener(new MyMouse());
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int roll = (rand.nextInt(6) + 1); //rolls the dice
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); //smoothes edges
g2.setColor(circleColor);
if (roll == 1) { //each body updates the associated dots
g2.fillOval(325, 325, circW, circH);
g2.drawOval(325, 325, circW, circH);
}
if (roll == 2) {
g2.fillOval(circX, circY, circW, circH);
g2.drawOval(circX, circY, circW, circH);
g2.fillOval(600, 600, circW, circH);
g2.drawOval(600, 600, circW, circH);
}
if (roll == 3) {
g2.fillOval(circX, 600, circW, circH);
g2.drawOval(circX, 600, circW, circH);
g2.fillOval(325, 325, circW, circH);
g2.drawOval(325, 325, circW, circH);
g2.fillOval(600, circY, circW, circH);
g2.drawOval(600, circY, circW, circH);
}
if (roll == 4) {
g2.fillOval(circX, circY, circW, circH);
g2.drawOval(circX, circY, circW, circH);
g2.fillOval(600, circY, circW, circH);
g2.drawOval(600, circY, circW, circH);
g2.fillOval(circX, 600, circW, circH);
g2.drawOval(circX, 600, circW, circH);
g2.fillOval(600, 600, circW, circH);
g2.drawOval(600, 600, circW, circH);
}
if (roll == 5) {
g2.fillOval(circX, circY, circW, circH);
g2.drawOval(circX, circY, circW, circH);
g2.fillOval(600, circY, circW, circH);
g2.drawOval(600, circY, circW, circH);
g2.fillOval(600, 600, circW, circH);
g2.drawOval(600, 600, circW, circH);
g2.fillOval(circX, 600, circW, circH);
g2.drawOval(circX, 600, circW, circH);
g2.fillOval(325, 325, circW, circH);
g2.drawOval(325, 325, circW, circH);
}
if (roll == 6) {
g2.fillOval(circX, circY, circW, circH);
g2.drawOval(circX, circY, circW, circH);
g2.fillOval(600, circY, circW, circH);
g2.drawOval(600, circY, circW, circH);
g2.fillOval(600, 325, circW, circH);
g2.drawOval(600, 325, circW, circH);
g2.fillOval(600, 600, circW, circH);
g2.drawOval(600, 600, circW, circH);
g2.fillOval(circX, 325, circW, circH);
g2.drawOval(circX, 325, circW, circH);
g2.fillOval(circX, 600, circW, circH);
g2.drawOval(circX, 600, circW, circH);
}
}
public void updateVal(int i) { //takes an int i between 1 and 6 and updates the face
if (i < 1 || i > 6) {
new IndexOutOfBoundsException("Choose a number between 1 and 6!");
}
else {
//here the face of the die should be updated according to what value of i is passed through
repaint();
}
}
private class MyMouse extends MouseAdapter {
Random rand = new Random();
public void mousePressed(MouseEvent e) {
int roll = rand.nextInt(6); //re-roll dice on click
repaint(); //repaint components accordingly
}
}
private static void createAndShowGui() { //creation of GUI visuals
JFrame frame = new JFrame("Die Roller");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new Die());
frame.setSize(800, 800);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
感谢您的帮助
答案 0 :(得分：2)
您需要将随机化逻辑与图形部分分离。那么我们有两个选择：
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package weekThree;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.util.*;
@SuppressWarnings("serial")
public class Die extends JPanel {
static Random rand = new Random();
// make roll a field to be seen by all methods
private int roll;
private Color circleColor = Color.BLACK;
private int circX = 75;
private int circY = circX;
private int circW = 75;
private int circH = circW;
public Die() {
addMouseListener(new MyMouse());
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// remove the randomize logic from here
//int roll = (rand.nextInt(6) + 1); //rolls the dice
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); //smoothes edges
g2.setColor(circleColor);
if (roll == 1) { //each body updates the associated dots
g2.fillOval(325, 325, circW, circH);
g2.drawOval(325, 325, circW, circH);
}
if (roll == 2) {
g2.fillOval(circX, circY, circW, circH);
g2.drawOval(circX, circY, circW, circH);
g2.fillOval(600, 600, circW, circH);
g2.drawOval(600, 600, circW, circH);
}
if (roll == 3) {
g2.fillOval(circX, 600, circW, circH);
g2.drawOval(circX, 600, circW, circH);
g2.fillOval(325, 325, circW, circH);
g2.drawOval(325, 325, circW, circH);
g2.fillOval(600, circY, circW, circH);
g2.drawOval(600, circY, circW, circH);
}
if (roll == 4) {
g2.fillOval(circX, circY, circW, circH);
g2.drawOval(circX, circY, circW, circH);
g2.fillOval(600, circY, circW, circH);
g2.drawOval(600, circY, circW, circH);
g2.fillOval(circX, 600, circW, circH);
g2.drawOval(circX, 600, circW, circH);
g2.fillOval(600, 600, circW, circH);
g2.drawOval(600, 600, circW, circH);
}
if (roll == 5) {
g2.fillOval(circX, circY, circW, circH);
g2.drawOval(circX, circY, circW, circH);
g2.fillOval(600, circY, circW, circH);
g2.drawOval(600, circY, circW, circH);
g2.fillOval(600, 600, circW, circH);
g2.drawOval(600, 600, circW, circH);
g2.fillOval(circX, 600, circW, circH);
g2.drawOval(circX, 600, circW, circH);
g2.fillOval(325, 325, circW, circH);
g2.drawOval(325, 325, circW, circH);
}
if (roll == 6) {
g2.fillOval(circX, circY, circW, circH);
g2.drawOval(circX, circY, circW, circH);
g2.fillOval(600, circY, circW, circH);
g2.drawOval(600, circY, circW, circH);
g2.fillOval(600, 325, circW, circH);
g2.drawOval(600, 325, circW, circH);
g2.fillOval(600, 600, circW, circH);
g2.drawOval(600, 600, circW, circH);
g2.fillOval(circX, 325, circW, circH);
g2.drawOval(circX, 325, circW, circH);
g2.fillOval(circX, 600, circW, circH);
g2.drawOval(circX, 600, circW, circH);
}
}
public void updateVal(int i) { //takes an int i between 1 and 6 and updates the face
if (i < 1 || i > 6) {
new IndexOutOfBoundsException("Choose a number between 1 and 6!");
}
else {
//here the face of the die should be updated according to what value of i is passed through
// static assinment and 'make the graphic'
roll = i;
repaint();
}
}
private class MyMouse extends MouseAdapter {
Random rand = new Random();
public void mousePressed(MouseEvent e) {
//
// updateVal(2); // can be used for test
// randomize and 'make the graphic'
roll = rand.nextInt(6); //re-roll dice on click
repaint(); //repaint components accordingly
}
}
private static void createAndShowGui() { //creation of GUI visuals
JFrame frame = new JFrame("Die Roller");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new Die());
frame.setSize(800, 800);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}