Question

我正在开发一个使用swing gui在java中生成和解决数独谜题的程序。我遇到一个问题，我在JTextField上使用.setText（）方法，但文本没有更新。

这是我的代码：

主要课程：

package sudoku;

public class SudokuSolver {

    public static void main(String[] args) {

        GUI gui = new GUI();
        gui.setVisible(true);

    }

}

GUI类：

package sudoku;

import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JButton;
import java.awt.Window.Type;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class GUI extends JFrame implements ActionListener {

    private JPanel contentPane;
    private Puzzle puzzle = new Puzzle();
    private Board board = new Board();
    private int[][] puzz = new int[9][9];

    // GUI Constructor
    public GUI() {

        // set up window
        setResizable(false);
        setTitle("Sudoku Solver");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 300, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        contentPane.setLayout(new BorderLayout(0, 0));
        setContentPane(contentPane);

        // set up button panel
        JPanel buttons = new JPanel();
        contentPane.add(buttons, BorderLayout.SOUTH);

        // set up generate button
        JButton genButton = new JButton("Generate");
        genButton.setMnemonic('g');
        buttons.add(genButton);
        genButton.addActionListener(this);

        // set up solve button
        JButton solveButton = new JButton("Solve");
        solveButton.setMnemonic('s');
        buttons.add(solveButton);
        solveButton.addActionListener(this);

        // set up board
        contentPane.add(board, BorderLayout.CENTER);
    }

    // Button listener
    public void actionPerformed(ActionEvent e) {

        String cmd = e.getActionCommand();

        if (cmd == "Generate") {
            // generate puzzle
            puzz = puzzle.generate();

        } else if (cmd == "Solve") {
            // solve puzzle
            puzz = puzzle.solve(puzz);

        }

        // display puzzle on the board
        board.fill(puzz);

    }

}

董事会成员：

package sudoku;

import java.awt.Color;
import java.awt.GridLayout;

import javax.swing.BorderFactory;
import javax.swing.JPanel;

public class Board extends JPanel {

    // 9x9 board sections
    private BoardSection nw = new BoardSection();
    private BoardSection n = new BoardSection();
    private BoardSection ne = new BoardSection();
    private BoardSection w = new BoardSection();
    private BoardSection c = new BoardSection();
    private BoardSection e = new BoardSection();
    private BoardSection sw = new BoardSection();
    private BoardSection s = new BoardSection();
    private BoardSection se = new BoardSection();

    // array of sections
    private BoardSection[] sections = { nw, n, ne, w, c, e, sw, s, se };

    // Board Constructor
    public Board() {

        // 3x3 grid layout
        setLayout(new GridLayout(3, 3));

        // border
        setBorder(BorderFactory.createLineBorder(Color.BLACK, 2));

        // add board sections to board
        for (int i = 0; i < sections.length; i++) {
            sections[i] = new BoardSection();
            add(sections[i]);
        }

    }

    // fill the board with data
    public void fill(int[][] data) {

        // create data sections
        String[][] nwData = new String[3][3];
        String[][] nData = new String[3][3];
        String[][] neData = new String[3][3];
        String[][] wData = new String[3][3];
        String[][] cData = new String[3][3];
        String[][] eData = new String[3][3];
        String[][] swData = new String[3][3];
        String[][] sData = new String[3][3];
        String[][] seData = new String[3][3];

        // break data into data sections
        nwData = createSection(data, 0, 0);
        nData = createSection(data, 3, 0);
        neData = createSection(data, 6, 0);
        wData = createSection(data, 0, 3);
        cData = createSection(data, 3, 3);
        eData = createSection(data, 6, 3);
        swData = createSection(data, 0, 6);
        sData = createSection(data, 3, 6);
        seData = createSection(data, 6, 6);

        // fill board section with data section
        nw.fillSection(nwData);
        n.fillSection(nData);
        ne.fillSection(neData);
        w.fillSection(wData);
        c.fillSection(cData);
        e.fillSection(eData);
        sw.fillSection(swData);
        s.fillSection(sData);
        se.fillSection(seData);

    }

    // split data into 3x3 section with 0,0 starting at x, y then convert to
    // string
    private String[][] createSection(int[][] data, int x, int y) {

        int[][] intSection = new int[3][3];
        String[][] strSection = new String[3][3];

        // break into section
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                intSection[i][j] = data[i + x][j + y];
            }
        }
        // convert section to string
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {

                strSection[i][j] = Integer.toString(intSection[i][j]);

            }

        }

        return strSection;
    }

}

BoardSection类：

package sudoku;

import java.awt.Color;
import java.awt.GridLayout;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.BorderFactory;

public class BoardSection extends JPanel {

    // each square
    private JTextField nw = new JTextField();
    private JTextField n = new JTextField();
    private JTextField ne = new JTextField();
    private JTextField w = new JTextField();
    private JTextField c = new JTextField();
    private JTextField e = new JTextField();
    private JTextField sw = new JTextField();
    private JTextField s = new JTextField();
    private JTextField se = new JTextField();

    // array of the squares
    private JTextField[] fields = new JTextField[] { nw, n, ne, w, c, e, sw, s,
            se };

    // Board Section Constructor
    public BoardSection() {
        // 3x3 grid layout
        setLayout(new GridLayout(3, 3));

        // border
        setBorder(BorderFactory.createLineBorder(Color.BLACK, 1));

        // add all fields to the board section
        for (int i = 0; i < fields.length; i++) {
            fields[i] = new JTextField(1);
            fields[i].setHorizontalAlignment(JTextField.CENTER);
            fields[i].setEditable(false);
            add(fields[i]);
        }

    }

    // Display the data on the board
    public void fillSection(String[][] data) {

        int x = 0;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                fields[x].setText(data[i][j]);
                x++;

            }
        }
    }

}

我还有另一个名为Puzzle的类，其中有一个generate（）和一个solve（）方法，它们都返回int [] []。我不相信它中的任何内容与问题有关，所以我在空间中省略它。

问题在于这一行是BoardSection类：

fields[x].setText(data[i][j]);

我没有收到任何错误消息，但是它没有更新文本。我尝试用＆＃34; Z＆＃34;替换数据[i] [j]。看问题是否是我传递的数据，但它仍然不能只使用一个简单的字符串。但是我确实尝试将以下行放在BoardSection构造函数方法内部的for循环中并显示DID。

fields[i].setText("0");

任何人都可以解释为什么它在构造函数中有效但在调用fillSection（）方法时却没有吗？

Answer 1

你的意思是只填充第一个字段吗？您永远不会将x变量更新为0的其他任何内容吗？

public void fillSection(String[][] data) {
    data = new String[3][3];
    int x = 0; // This never changes?
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            fields[x].setText(data[i][j]);
        }
    }
}

你可以试试......

fields[i * j].setText(data[i][j]);

或者实际相应地修改x参数......

<强>更新...

您遇到的另一个问题是data变量传递给您的fillSection方法的阴影......

public void fillSection(String[][] data) {
    // Oh look, I've overridden every thing
    // you just gave with my own copy of the data!!
    data = new String[3][3];
    //...
}

<强>更新...

不知道这是否相关，但它仍然是一个问题......

您String比较错误... ==检查两个对象是否共享相同的内存空间，String永远不会出现这种情况（以这种方式）

if (cmd == "Generate") {

相反，您应该使用String#equals来比较对象的内容......

if ("Generate".equals(cmd)) {

这意味着puzz永远不会更新，因此当您将其传递到您的字段时，它可能是空白的......

<强>更新...

又一个问题;）

在Board课程中，您要定义9个电路板部分......

private BoardSection nw = new BoardSection();
private BoardSection n = new BoardSection();
private BoardSection ne = new BoardSection();
private BoardSection w = new BoardSection();
private BoardSection c = new BoardSection();
private BoardSection e = new BoardSection();
private BoardSection sw = new BoardSection();
private BoardSection s = new BoardSection();
private BoardSection se = new BoardSection();
// array of sections
private BoardSection[] sections = {nw, n, ne, w, c, e, sw, s, se};

但是在你的构造函数中，你重新对它们进行了修改（在sections数组中）......

// Board Constructor
public Board() {

    //...//

    // add board sections to board
    for (int i = 0; i < sections.length; i++) {
        // Look ma, new Board!!
        sections[i] = new BoardSection();
        add(sections[i]);
    }

}

这意味着BoardSection s nw等从未实际添加到屏幕上......

相反，你应该简单地删除这些部分并直接使用数组......

public class Board extends JPanel {

    // array of sections
    private BoardSection[] sections;

    // Board Constructor
    public Board() {

        //...//

        // add board sections to board
        sections = new BoardSection[9];
        for (int i = 0; i < sections.length; i++) {
            sections[i] = new BoardSection();
            add(sections[i]);
        }

    }

    // fill the board with data
    public void fill(int[][] data) {

        // create data sections
        String[][] nwData = new String[3][3];
        String[][] nData = new String[3][3];
        String[][] neData = new String[3][3];
        String[][] wData = new String[3][3];
        String[][] cData = new String[3][3];
        String[][] eData = new String[3][3];
        String[][] swData = new String[3][3];
        String[][] sData = new String[3][3];
        String[][] seData = new String[3][3];

        // break data into data sections
        nwData = createSection(data, 0, 0);
        nData = createSection(data, 3, 0);
        neData = createSection(data, 6, 0);
        wData = createSection(data, 0, 3);
        cData = createSection(data, 3, 3);
        eData = createSection(data, 6, 3);
        swData = createSection(data, 0, 6);
        sData = createSection(data, 3, 6);
        seData = createSection(data, 6, 6);

        // fill board section with data section
        sections[0].fillSection(nwData);
        sections[1].fillSection(nData);
        sections[2].fillSection(neData);
        sections[3].fillSection(wData);
        sections[4].fillSection(cData);
        sections[5].fillSection(eData);
        sections[6].fillSection(swData);
        sections[7].fillSection(sData);
        sections[8].fillSection(seData);

    }

Answer 2

调用setText()只会更新JTextField的模型。换句话说，JTextField存储一个内部String，其中包含您发送它的值。但是，视图（即屏幕上显示的内容）未更新。这实际上是一件好事，因为绘画很慢。如果每次在Sudoku程序中调用setText()时都会更新UI，则必须更新81次。

您可以通过在invalidate()的任何子类上调用Component来强制更新视图。在您的情况下，您可能应该在主invalidate()或包含所有JFrame的{{1}}上致电JPanel。这将导致GUI刷新一次，而不是之前提到的81次。

P.S。有关更多信息，我建议您研究模型 - 视图 - 控制器设计模式。

JAVA SWING：无法更改JTextField的文本

2 个答案: