Простой ответ, GridLayout
не собирается делать то, что вы хотите, это просто не достаточно гибкой, а ...
Вы могли бы ...
Изменить менеджер компоновки и сделать использование из JSeparator
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSeparator;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class SudokuGrid {
public static void main(String[] args) {
new SudokuGrid();
}
public SudokuGrid() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static class TestPane extends JPanel {
private static final int ROWS = 9;
private static final int COLUMNS = 9;
int fontSize = 30;
public TestPane() {
JTextField[][] inputBoxes = new JTextField[ROWS][COLUMNS];
Font font = new Font("Helvetica", Font.BOLD, fontSize);
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.fill = GridBagConstraints.BOTH;
gbc.weightx = 1;
gbc.weighty = 1;
gbc.gridy = 0;
GridBagConstraints split = new GridBagConstraints();
split.fill = GridBagConstraints.BOTH;
split.weightx = 1;
split.gridx = 0;
split.gridwidth = GridBagConstraints.REMAINDER;
// outer loop to create the rows
for (int rows = 0; rows < ROWS; rows++) {
gbc.gridy++;
// inner loop to create the columns
for (int columns = 0; columns < COLUMNS; columns++) {
gbc.gridx = columns;
// make text fields empty
inputBoxes[rows][columns] = new JTextField(1);
// add text fields to the frame
add(inputBoxes[rows][columns], gbc);
// center text in each text box
inputBoxes[rows][columns].setHorizontalAlignment(JTextField.CENTER);
// apply font to each text box
inputBoxes[rows][columns].setFont(font);
} // end of columns loop
if ((rows + 1) % 3 == 0) {
System.out.println("Split");
split.gridy = gbc.gridy + 1;
gbc.gridy += 2;
JSeparator sep = new JSeparator(JSeparator.HORIZONTAL);
add(sep, split);
}
} // end of rows loop
}
}
}
Вы могли бы ...
Сделать свой собственный "раздвоение" компонент за счет использования пользовательских живописи
public static class HorizontalSplit extends JPanel {
public HorizontalSplit() {
setOpaque(false);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(0, 3);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
int y = (getHeight() - 3)/2;
BasicStroke stroke = new BasicStroke(3, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND);
g2d.setStroke(stroke);
g2d.drawLine(0, y, getWidth(), y);
g2d.dispose();
}
}
Что бы просто заменить JSeparator
...
if ((rows + 1) % 3 == 0) {
System.out.println("Split");
split.gridy = gbc.gridy + 1;
gbc.gridy += 2;
JPanel sep = new HorizontalSplit();
add(sep, split);
}
Вы могли бы ...
Используйте составную компоновку и MatteLayout
...
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.MatteBorder;
public class SudokuGrid {
public static void main(String[] args) {
new SudokuGrid();
}
public SudokuGrid() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public static class TestPane extends JPanel {
private static final int ROWS = 9;
private static final int COLUMNS = 9;
int fontSize = 30;
public TestPane() {
JTextField[][] inputBoxes = new JTextField[ROWS][COLUMNS];
Font font = new Font("Helvetica", Font.BOLD, fontSize);
setLayout(new GridBagLayout());
GridBagConstraints groupContraint = new GridBagConstraints();
groupContraint.fill = GridBagConstraints.BOTH;
groupContraint.weightx = 1;
groupContraint.weighty = 1;
groupContraint.gridwidth = GridBagConstraints.REMAINDER;
JPanel group = new JPanel(new GridLayout(3, COLUMNS));
group.setBorder(new MatteBorder(0, 0, 1, 0, Color.BLACK));
// outer loop to create the rows
for (int rows = 0; rows < ROWS; rows++) {
// inner loop to create the columns
for (int columns = 0; columns < COLUMNS; columns++) {
// make text fields empty
inputBoxes[rows][columns] = new JTextField(1);
// add text fields to the frame
group.add(inputBoxes[rows][columns]);
// center text in each text box
inputBoxes[rows][columns].setHorizontalAlignment(JTextField.CENTER);
// apply font to each text box
inputBoxes[rows][columns].setFont(font);
} // end of columns loop
if ((rows + 1) % 3 == 0) {
add(group, groupContraint);
group = new JPanel(new GridLayout(3, COLUMNS));
group.setBorder(new MatteBorder(0, 0, 1, 0, Color.BLACK));
}
} // end of rows loop
}
}
}
Используйте 'LineBorder', использовать [' JSeparator'] (https://docs.oracle.com/javase/tutorial/uiswing/components/separator.html), написать компонент, который предназначен для рисования линии – MadProgrammer