Java Swing 图形

Question

我用 Java 编写了一个解决数独问题的代码，并使用 Java Applet 来设计它。现在，我尝试使用 Java Swing 使其看起来更好，并添加一些功能，例如“保存”数独板等。不幸的是，我对 Java Swing 不太熟悉，并且在使用 Graphics(绘制 9x9 的板)时遇到一些问题。我也不明白为什么我不能在同一个类中扩展 JFrame 和 JPanel 。

import java.applet.*;

import javax.swing.*;
import javax.swing.border.*;

import java.awt.*;
import java.awt.event.*;
import java.net.URL;
import java.util.Scanner;

class Sudoku2 extends JPanel implements ActionListener, MouseListener,
        ItemListener {

    public JPanel createContentPane() {

        JPanel GUI = new JPanel();
        GUI.setLayout(null);

        JPanel titlePanel = new JPanel();
        titlePanel.setLayout(null);
        titlePanel.setLocation(10, 0);
        titlePanel.setSize(250, 30);
        GUI.add(titlePanel);

        JPanel scorePanel = new JPanel();
        scorePanel.setLayout(null);
        scorePanel.setLocation(10, 40);
        scorePanel.setSize(250, 30);
        GUI.add(scorePanel);

        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout(null);
        buttonPanel.setLocation(0, 0);
        buttonPanel.setSize(300, 200);
        GUI.add(buttonPanel);

        JButton solve = new JButton("Solve");
        solve.setLocation(20, 100);
        solve.setSize(100, 30);
        buttonPanel.add(solve);

        JButton clear_digit = new JButton("Clear Digit");
        clear_digit.setLocation(20, 140);
        clear_digit.setSize(100, 30);
        buttonPanel.add(clear_digit);

        GUI.setOpaque(true);
        return GUI;
    }

    public JMenuBar createMenuBar() {

        JMenuBar menuBar = new JMenuBar();

        JMenu Menu = new JMenu("File");
        menuBar.add(Menu);

        JMenuItem new1 = new JMenuItem("New");
        new1.addActionListener(this);
        JMenuItem load = new JMenuItem("Load");
        load.addActionListener(this);
        JMenuItem save1 = new JMenuItem("Save");
        save1.addActionListener(this);
        JMenuItem save2 = new JMenuItem("Save As...");
        save2.addActionListener(this);

        Menu.add(new1);
        Menu.add(load);
        Menu.add(save1);
        Menu.add(save2);

        return menuBar;
    }

    private static void createAndShowGUI() {

        JFrame frame = new JFrame("Sudoku Solver");

        Sudoku2 demo = new Sudoku2();

        frame.setJMenuBar(demo.createMenuBar());

        frame.setContentPane(demo.createContentPane());

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.setSize(500, 500);

        frame.setVisible(true);
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);

        g.drawLine(50, 50, 100, 100);
    }

    @Override
    public void mouseClicked(MouseEvent e) {
        // TODO Auto-generated method stub

    }

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

    }

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

    }

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

    }

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

    }

    public void actionPerformed(ActionEvent e) {

    }

    public void itemStateChanged(ItemEvent e) {

    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();

            }
        });

    }

}
`

Answer 1

您无法在一个类中扩展 JFrame 和 JPanel，因为 Java 不允许多重继承。

如果您不熟悉 Swing Graphic，您应该省去图形绘制的麻烦。

你可以做这样的事情来让你的生活更轻松。

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class SudokuBoard extends JPanel implements 
        ActionListener, MouseListener, ItemListener {

    private JPanel board;
    JTextField[] numberFields;

    public SudokuBoard() {
        super();
        numberFields = new JTextField[81];
        board = createContentPane();
    }

    public JPanel getBoard() {
        return board;
    }

    private JPanel createContentPane() {

        JPanel board = new JPanel();
        board.setLayout(new GridLayout(9, 9, 1, 1));

        for (int i = 0; i < numberFields.length; i++) {
            numberFields[i] = new JTextField();
            numberFields[i].setHorizontalAlignment(JTextField.CENTER);
            numberFields[i].setFont(new Font("Ariel", Font.BOLD, 25));
            numberFields[i].setText((i % 9)+1+"");

            //set border
            if ((i+1) % 3 == 0) {
                numberFields[i].setBorder(BorderFactory.createMatteBorder(1, 1, 1, 5, Color.black));
            }
            if (i > 17 && i < 27) {
                numberFields[i].setBorder(BorderFactory.createMatteBorder(1, 1, 5, 1, Color.black));
            }
            if (i > 44 && i < 54) {
                numberFields[i].setBorder(BorderFactory.createMatteBorder(1, 1, 5, 1, Color.black));
            }

            board.add(numberFields[i]);
        }

        numberFields[20].setBorder(BorderFactory.createMatteBorder(1, 1, 5, 5, Color.black));
        numberFields[23].setBorder(BorderFactory.createMatteBorder(1, 1, 5, 5, Color.black));
        numberFields[26].setBorder(BorderFactory.createMatteBorder(1, 1, 5, 5, Color.black));
        numberFields[47].setBorder(BorderFactory.createMatteBorder(1, 1, 5, 5, Color.black));
        numberFields[50].setBorder(BorderFactory.createMatteBorder(1, 1, 5, 5, Color.black));
        numberFields[53].setBorder(BorderFactory.createMatteBorder(1, 1, 5, 5, Color.black));

        return board;
    }

    public JMenuBar createMenuBar() {

        JMenuBar menuBar = new JMenuBar();

        JMenu Menu = new JMenu("File");
        menuBar.add(Menu);

        JMenuItem new1 = new JMenuItem("New");
        new1.addActionListener(this);
        JMenuItem load = new JMenuItem("Load");
        load.addActionListener(this);
        JMenuItem save1 = new JMenuItem("Save");
        save1.addActionListener(this);
        JMenuItem save2 = new JMenuItem("Save As...");
        save2.addActionListener(this);

        Menu.add(new1);
        Menu.add(load);
        Menu.add(save1);
        Menu.add(save2);

        return menuBar;
    }

    private static void createAndShowGUI() {

        JFrame frame = new JFrame("Sudoku Solver (Try Save)");
        SudokuBoard demo = new SudokuBoard();

        frame.setJMenuBar(demo.createMenuBar());
        frame.setContentPane(demo.getBoard());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(500, 500);
        frame.setVisible(true);
    }

    @Override
    public void mouseClicked(MouseEvent e) {
        // TODO Auto-generated method stub

    }

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

    }

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

    }

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

    }

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

    }

    public void actionPerformed(ActionEvent e) {
        if (e.getActionCommand().equals("Save")) {
            int[][] numbers = new int[9][9];
            int c = 0;
            for(int i = 0; i < numbers.length; i++) {
                for (int j = 0; j < numbers[i].length; j++) {

                    //check for non-int
                    numbers[i][j] = Integer.parseInt(numberFields[c].getText());

                    c++; //awesome!
                }
            }

            for(int i = 0; i < numbers.length; i++) {
                System.out.print("[");
                for (int j = 0; j < numbers[i].length; j++) {
                    System.out.print(numbers[i][j]+" ");
                }
                System.out.println("]");
            }

            //save this 2-d array

            System.out.println("Saving...");
        }
    }

    public void itemStateChanged(ItemEvent e) {

    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}