I wrote a program that creates a sudoku board according to the difficulty level chosen by the user. There's a basic GUI using JFrame and JPanel. The board itself is built using a 2D array of JTextFields to allow for editing by the user and I made a table of JButtons representing digits 1-9. I'm trying to make it so when I press a digit button while my cursor is on the relevant text field, it'll input that number to the field. I think there's a problem with how I defined the buttons but would love a hand. By the way, this is my first official stack overflow question so thanks in advance to all who help :)
/*Java Program to solve Sudoku problem using Backtracking*/
import javax.swing.*;
import javax.swing.border.Border;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.*;
public class Solver extends Board {
Solver(int N, int K) {
super(N, K);
}
private static void createWindow() {
JFrame frame = new JFrame("Sudoku");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
createUI(frame);
frame.setSize(250, 80);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private static void createUI(final JFrame frame) {
JPanel panel = new JPanel();
LayoutManager layout = new FlowLayout();
panel.setLayout(layout);
JButton button = new JButton("Play");
button.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
String result = (String) JOptionPane.showInputDialog(
frame,
"Difficulty Glossary:\n\n Hard - 50/81 blank spaces\n Medium - 35/81 blank spaces\n Easy - 20/81 blank spaces\n\nChoose your desired difficulty:\n\tHard: 1\n\tMedium: 2\n\tEasy: 3\nIf your input doesn't match one of these digits, the board generated will be on easy mode.",
"Difficulty Glossary",
JOptionPane.PLAIN_MESSAGE,
null,
null,
"3"
);
optionBoard();
play(Integer.parseInt(result));
}
});
panel.add(button);
frame.getContentPane().add(panel, BorderLayout.CENTER);
}
public static void optionBoard(){
}
public static void play(int level) {
int N = 9, K = 0;
switch (level) {
case 1:
K = 50;
break;
case 2:
K = 35;
break;
default:
K = 20;
break;
}
Solver sudoku = new Solver(N, K);
sudoku.fillValues();
createBoard(sudoku.puzzle);
}
public static void createBoard(int[][] puzzle) {
final Border fieldBorder = BorderFactory.createLineBorder(Color.BLACK);
final JPanel grid = new JPanel(new GridLayout(9, 9));
for (int i = 0; i < 9; i ) {
for (int j = 0; j < 9; j ) {
final JTextField field = new JTextField(2);
if (puzzle[i][j] != 0) {
field.setText(puzzle[i][j] "");
} else {
field.setText("");
}
field.setHorizontalAlignment(JTextField.CENTER); //Center text horizontally in the text field.
field.setBorder(fieldBorder); //Add the colored border.
grid.add(field);
}
}
final JPanel digits = new JPanel(new GridLayout(3, 3));
int num=1;
for (int i = 1; i < 4; i ) {
for (int j = 1; j < 4; j ) {
final JButton digit = new JButton(num "");
num ;
digits.add(digit);
}
}
final JPanel centeredGrid = new JPanel(new GridBagLayout());
centeredGrid.add(digits);
centeredGrid.add(grid);
final JFrame frame = new JFrame("Sudoku Board");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(centeredGrid);
frame.setSize(400,400);
frame.setVisible(true);
JButton button = new JButton("Check");
button.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
}
});
// centeredGrid.add(button);
}
// Driver code
public static void main(String[] args) {
createWindow();
}
}
I've only provided the relevant GUI class since the mathematical logic part of building the board is solid and works fine. That's what the Board class is.
CodePudding user response：
It sounds like a great project. May I suggest you choose to go with either the JTextField, or JComboBox, to make it easier for you. If you want to use JTextField, you will need to use a parameter check to verify that a number between 1 and 9 was entered. Whereas a JComboBox provides the acceptable values. This way you aren't using one UI to edit another UI before processing the input.
CodePudding user response：
One way to do this could be to:
- Put the JTextFields in an
ArrayList<JTextField>so that you can get them later as you will likely need access to them during the game - Give the class a field,
private JTextField selectedField = null;, set initially tonull. This will point to the last JTextField that has been clicked (the last one to gain focus) - Give the JTextFields FocusListeners when created. If any field gains focus, set the selectedField to refer to it
- In your number JButton's ActionListener, check that selectedField is not null
- If not null, then set the button's actionCommand (its text) to be the selectedField's text.
Also, if you need more help, consider creating and posting a valid 
import java.awt.Color;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
public class Solver2 extends JPanel {
private static final float FONT_SIZE = 24f;
private int gridEdgeSize = 9;
private JTextField[][] fieldGrid = new JTextField[gridEdgeSize][gridEdgeSize];
private List<JTextField> fieldList = new ArrayList<>();
private JTextField selectedField = null;
public Solver2() {
JPanel gridPanel = new JPanel(new GridLayout(gridEdgeSize, gridEdgeSize, 2, 2));
gridPanel.setBorder(BorderFactory.createLineBorder(Color.BLACK, 2));
gridPanel.setBackground(Color.BLACK);
for (int i = 0; i < gridEdgeSize; i ) {
for (int j = 0; j < gridEdgeSize; j ) {
JTextField textField = new JTextField(2);
textField.setHorizontalAlignment(SwingConstants.CENTER);
textField.setFont(textField.getFont().deriveFont(Font.BOLD, FONT_SIZE));
textField.setBorder(null);
textField.addFocusListener(new TextFieldFocusListener());
gridPanel.add(textField);
fieldList.add(textField);
}
}
JPanel numberPanel = new JPanel(new GridLayout(0, 3));
for (int i = 1; i < 10; i ) {
String text = String.valueOf(i);
JButton button = new JButton(text);
button.setFont(button.getFont().deriveFont(Font.BOLD, FONT_SIZE));
button.addActionListener(e -> buttonListener(e));
numberPanel.add(button);
}
setLayout(new GridLayout(1, 2));
add(gridPanel);
add(numberPanel);
}
private void buttonListener(ActionEvent e) {
String text = e.getActionCommand();
if (selectedField != null) {
selectedField.setText(text);
}
}
private class TextFieldFocusListener extends FocusAdapter {
@Override
public void focusGained(FocusEvent e) {
selectedField = (JTextField) e.getComponent();
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
Solver2 mainPanel = new Solver2();
JFrame frame = new JFrame("GUI");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
});
}
}
Side Note
If you want to restrict the JTextField from allowing keyboard or copy/paste entry, then one way could be to use a DocumentFilter added to each JTextField's Document.
You could give the class a private boolean field, say,
public class Solver2 extends JPanel {
// .....
private boolean blockTextInput = true;
and a private nested class that extends DocumentFilter. This class will prevent the document from allowing String inserts, removals or replacements as long as blockTextInput is true:
private class MyDocFilter extends DocumentFilter {
@Override
public void insertString(FilterBypass fb, int offset, String string, AttributeSet attr)
throws BadLocationException {
if (blockTextInput) {
return;
}
super.insertString(fb, offset, string, attr);
}
@Override
public void remove(FilterBypass fb, int offset, int length) throws BadLocationException {
if (blockTextInput) {
return;
}
super.remove(fb, offset, length);
}
@Override
public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs)
throws BadLocationException {
if (blockTextInput) {
return;
}
super.replace(fb, offset, length, text, attrs);
}
}
then in the JTextField creation loop, set the filter:
for (int i = 0; i < gridEdgeSize; i ) {
for (int j = 0; j < gridEdgeSize; j ) {
JTextField textField = new JTextField(2);
textField.setHorizontalAlignment(SwingConstants.CENTER);
textField.setFont(textField.getFont().deriveFont(Font.BOLD, FONT_SIZE));
textField.setBorder(null);
textField.addFocusListener(new TextFieldFocusListener());
// ***** here ****
((PlainDocument) textField.getDocument()).setDocumentFilter(new MyDocFilter());
gridPanel.add(textField);
fieldList.add(textField);
}
}
Then change the number JButton's ActionListeners to change blockTextInput before and after setting the JTextField's text:
private void buttonListener(ActionEvent e) {
String text = e.getActionCommand();
if (selectedField != null) {
blockTextInput = false;
selectedField.setText(text);
blockTextInput = true;
}
}
Done
The latest iteration of the program that uses a single FocusListener and a DocumentFilter:
import java.awt.Color;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;
import javax.swing.text.PlainDocument;
@SuppressWarnings("serial")
public class Solver2 extends JPanel {
private static final float FONT_SIZE = 24f;
private int gridEdgeSize = 9;
private List<JTextField> fieldList = new ArrayList<>();
private JTextField selectedField = null;
private boolean blockTextInput = true;
public Solver2() {
JPanel gridPanel = new JPanel(new GridLayout(gridEdgeSize, gridEdgeSize, 2, 2));
gridPanel.setBorder(BorderFactory.createLineBorder(Color.BLACK, 2));
gridPanel.setBackground(Color.BLACK);
FocusListener textFieldFocusListenr = new TextFieldFocusListener();
for (int i = 0; i < gridEdgeSize; i ) {
for (int j = 0; j < gridEdgeSize; j ) {
JTextField textField = new JTextField(2);
textField.setHorizontalAlignment(SwingConstants.CENTER);
textField.setFont(textField.getFont().deriveFont(Font.BOLD, FONT_SIZE));
textField.setBorder(null);
textField.addFocusListener(textFieldFocusListenr);
((PlainDocument) textField.getDocument()).setDocumentFilter(new MyDocFilter());
gridPanel.add(textField);
fieldList.add(textField);
}
}
JPanel numberPanel = new JPanel(new GridLayout(0, 3));
for (int i = 1; i < 10; i ) {
String text = String.valueOf(i);
JButton button = new JButton(text);
button.setFont(button.getFont().deriveFont(Font.BOLD, FONT_SIZE));
button.addActionListener(e -> buttonListener(e));
numberPanel.add(button);
}
setLayout(new GridLayout(1, 2));
add(gridPanel);
add(numberPanel);
}
private void buttonListener(ActionEvent e) {
String text = e.getActionCommand();
if (selectedField != null) {
blockTextInput = false;
selectedField.setText(text);
blockTextInput = true;
}
private class TextFieldFocusListener extends FocusAdapter {
@Override
public void focusGained(FocusEvent e) {
selectedField = (JTextField) e.getComponent();
}
}
private class MyDocFilter extends DocumentFilter {
@Override
public void insertString(FilterBypass fb, int offset, String string, AttributeSet attr)
throws BadLocationException {
if (blockTextInput) {
return;
}
super.insertString(fb, offset, string, attr);
}
@Override
public void remove(FilterBypass fb, int offset, int length) throws BadLocationException {
if (blockTextInput) {
return;
}
super.remove(fb, offset, length);
}
@Override
public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs)
throws BadLocationException {
if (blockTextInput) {
return;
}
super.replace(fb, offset, length, text, attrs);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
Solver2 mainPanel = new Solver2();
JFrame frame = new JFrame("GUI");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
});
}
}