java - 更新图形

Question

我在使用这段代码时遇到了一些问题，图形似乎出于某种奇怪的原因不想更新。我不知道如何解决这个问题，尝试解决这个问题真的很烦人，请帮忙!这是代码:

package org.jeopredy;

import java.awt.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.ArrayList;

import javax.swing.*;

public class Main extends JFrame {

public Main() {
    super("Jeopredy");
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    this.setSize(517, 640);
    this.setVisible(true);
    this.add(new panel());
    this.addMouseListener(new panel());
}

public static void main(String args[]) {
    new Main();
}

private class panel extends JPanel implements MouseListener {

    public Rectangle[][] tiles = new Rectangle[5][6];

    public boolean start, question, answer;

    public String[][] Catagories = { { "House of", "representitives" },
            { "Senate" }, { "President" }, { "Vice president" },
            { "Supreme court" } };

    public String[][] Questions = { { "1", "2", "3", "4", "5" },
            { "1", "2", "3", "4", "5" }, { "1", "2", "3", "4", "5" },
            { "1", "2", "3", "4", "5" }, { "1", "2", "3", "4", "5" } };

    public String[][] Answers = { { "", "", "", "", "" },
            { "", "", "", "", "" }, { "", "", "", "", "" },
            { "", "", "", "", "" }, { "", "", "", "", "" } };

    public Point q, a;

    public ArrayList<Point> used = new ArrayList<Point>();

    public panel() {
        start = true;
        for (int x = 0; x < 500; x += 100) {
            for (int y = 0; y < 600; y += 100) {
                tiles[x / 100][y / 100] = new Rectangle(x, y, 100, 100);
            }
        }
        repaint();
    }

    @Override
    public void paint(Graphics g) {
        // super.paintComponent(g);
             //g.setColor(Color.white);

         System.out.println("Start: " + start + " question: " + question
         + " answer: " + answer);
        if (start) {
            int i = 0;
            for (String[] str : Catagories) {
                if (str.length == 1) {
                    g.drawString(str[0], tiles[i][0].x, tiles[i][0].y + 20);
                } else {
                    g.drawString(str[0], tiles[i][0].x, tiles[i][0].y + 20);
                    g.drawString(str[1], tiles[i][0].x, tiles[i][0].y + 30);
                }
                i++;
            }
            for (Rectangle[] rect : tiles) {
                for (Rectangle r : rect) {
                    g.drawRect(r.x, r.y, r.width, r.height);
                }
            }
        } else if (question) {
            // System.out.println("QUeStionJOSNLN");
            g.drawString(Questions[q.x][q.y], 100, 100);
        }
        repaint();
    }

    @Override
    public void mouseClicked(MouseEvent arg0) {
        Point p = new Point(arg0.getPoint().x - 17, arg0.getPoint().y - 40);
        // repaint();
        if (start) {
            for (int x = 0; x < tiles.length; x++) {
                for (int y = 0; y < tiles[x].length; y++) {
                    if (tiles[x][y].contains(p) && y != 0) {
                        question = true;
                        start = false;
                        answer = false;
                        q = new Point(x, y - 1);
                        used.add(q);
                    }
                }
            }
        } else if (question) {
            answer = true;
            question = false;
            start = false;
        } else if (answer) {
            start = true;
            answer = false;
            question = false;
        }

    }

    @Override
    public void mouseEntered(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseExited(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mousePressed(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }

    @Override
    public void mouseReleased(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }
}
}

Answer 1

1. 首先，您永远不应该重写paint()。我认为这是您遇到问题的主要原因。

Difference between paint, paintComponent and paintComponents in Swing

1. 使用SwingUtilities.invokeLater()加载GUI

2. 不要扩展JFrame，完全不推荐，在上面的代码中也没有用

3. private class panel extends JPanel implements 类应该以大写字母开头，如MyPanel