GridBagLayout gridding not working

Question

I am trying to create the following GUI:

but the GUI that I make is:

What my grid looks like:

image: THE GRIDLAYOUT FOR THIS

I don't understand why I am getting this output since I have drawn a diagram to aid the code and it seems to work out.

The method addComp adds adds the input component to the input panel at a given (x, y) position and at a given component width and height.

Code:

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

public class GUIError extends JFrame {

    //initialise all the components
    JPanel mainPanel = new JPanel();
    JTextField txtDisplay = new JTextField();
    JButton btnA = new JButton("A");
    JButton btnB = new JButton("B");
    JButton btnC = new JButton("C");
    JButton btnD = new JButton("D");
    JButton btnE = new JButton("E");
    JButton btnF = new JButton("F");
    JButton btnWA = new JButton("WA");
    JButton btnWB = new JButton("WB");
    JButton btnWC = new JButton("WC");
    JButton btnWD = new JButton("WD");

    private void addComp(JPanel panel, JComponent comp, int xPos, int yPos, int compWidth, int compHeight) {

        GridBagConstraints gridConstraints = new GridBagConstraints();

        gridConstraints.gridx = xPos;
        gridConstraints.gridy = yPos;
        gridConstraints.gridwidth = compWidth;
        gridConstraints.gridheight = compHeight;
        gridConstraints.weightx = 0.5;
        gridConstraints.weighty = 0.5;
        gridConstraints.insets = new Insets(5, 5, 5, 5);
        gridConstraints.anchor = GridBagConstraints.CENTER;
        gridConstraints.fill = GridBagConstraints.BOTH;

        panel.add(comp, gridConstraints);

    }


    public static void main(String[] args) {
        try {
            for (UIManager.LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        }
        catch (Exception e) { }

        SwingUtilities.invokeLater(new Runnable() {

            public void run() {

                // create frame
                JFrame frame = new JFrame("Calculator");
                frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                frame.setLocationRelativeTo(null);
                Container c = frame.getContentPane();

                // create GUI within frame              
                new GUIError(c);

                // finish frame definition
                frame.pack();
                frame.setResizable(false);
                frame.setVisible(true);

            }

        });
    }

    public GUIError(Container cont) {

        cont.setPreferredSize(new Dimension(610, 250));

        // parent panel containes every other panel
        mainPanel.setLayout(new GridBagLayout());

        // text display
        txtDisplay.setEditable(false);
        addComp(mainPanel, txtDisplay, 0, 0, 12, 2); // width 16, height 2


        addComp(mainPanel, btnA, 0, 2, 2, 1);
        addComp(mainPanel, btnB, 2, 2, 2, 1);
        addComp(mainPanel, btnC, 4, 2, 2, 1);
        addComp(mainPanel, btnD, 6, 2, 2, 1);
        addComp(mainPanel, btnE, 8, 2, 2, 1);
        addComp(mainPanel, btnF, 10, 2, 2, 1);
        addComp(mainPanel, btnWA, 0, 3, 3, 1);
        addComp(mainPanel, btnWB, 3, 3, 3, 1);
        addComp(mainPanel, btnWC, 6, 3, 3, 1);
        addComp(mainPanel, btnWD, 9, 3, 3, 1);

        cont.add(mainPanel);
    }
}

Answer 1

It can easily be achieved by using GridBagLayout as seen in this example presented below. You simply need to take two JPanel one each for each ROW. Both using GridBagLayout, and add components to the first row, with weightx = 0.16 since each JButton is suppose to take this much area, and for the second row weightx = 0.25 since, this is the area occupied by each JButton along the X direction

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

public class GridBagExample {
    private static final int SIZE = 10;
    private JButton[] buttons;
    private GridBagConstraints gbc;

    public GridBagExample() {
        buttons = new JButton[SIZE];
        gbc = new GridBagConstraints();
        gbc.insets = new Insets(5, 5, 5, 5);
    }

    private void createAndDisplayGUI() {
        JFrame frame = new JFrame("Grid Game");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        JPanel contentPane = new JPanel();
        contentPane.setLayout(new GridLayout(2, 1, 5, 5));
        contentPane.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));

        JPanel topPanel = new JPanel();
        JTextField textField = new JTextField(10);
        //topPanel.add(textField);

        JPanel buttonPanel = new JPanel(new GridLayout(2, 1, 5, 5));
        JPanel headerPanel = new JPanel(new GridBagLayout());
        buttons[0] = new JButton("A");
        addComp(headerPanel, buttons[0], 0, 0, 0.16, 1.0, 1, 1, GridBagConstraints.BOTH);        
        buttons[1] = new JButton("B");
        addComp(headerPanel, buttons[1], 1, 0, 0.16, 1.0, 1, 1, GridBagConstraints.BOTH);
        buttons[2] = new JButton("C");
        addComp(headerPanel, buttons[2], 2, 0, 0.16, 1.0, 1, 1, GridBagConstraints.BOTH);
        buttons[3] = new JButton("D");
        addComp(headerPanel, buttons[3], 3, 0, 0.16, 1.0, 1, 1, GridBagConstraints.BOTH);
        buttons[4] = new JButton("E");
        addComp(headerPanel, buttons[4], 4, 0, 0.16, 1.0, 1, 1, GridBagConstraints.BOTH);
        buttons[5] = new JButton("F");
        addComp(headerPanel, buttons[5], 5, 0, 0.16, 1.0, 1, 1, GridBagConstraints.BOTH);

        JPanel footerPanel = new JPanel(new GridBagLayout());
        buttons[6] = new JButton("WA");
        addComp(footerPanel, buttons[6], 0, 0, 0.25, 1.0, 1, 1, GridBagConstraints.BOTH);
        buttons[7] = new JButton("WB");
        addComp(footerPanel, buttons[7], 1, 0, 0.25, 1.0, 1, 1, GridBagConstraints.BOTH);
        buttons[8] = new JButton("WC");
        addComp(footerPanel, buttons[8], 2, 0, 0.25, 1.0, 1, 1, GridBagConstraints.BOTH);
        buttons[9] = new JButton("WD");
        addComp(footerPanel, buttons[9], 3, 0, 0.25, 1.0, 1, 1, GridBagConstraints.BOTH);
        buttonPanel.add(headerPanel);
        buttonPanel.add(footerPanel);

        contentPane.add(textField);
        contentPane.add(buttonPanel);

        frame.setContentPane(contentPane);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private void addComp(JPanel panel, JComponent comp, int x, int y,
                                    double wx, double wy, int gw, int gh, int fill) {
        gbc.gridx = x;
        gbc.gridy = y;
        gbc.weightx = wx;
        gbc.weighty = wy;
        gbc.gridwidth = gw;
        gbc.gridheight = gh;
        gbc.fill = fill;

        panel.add(comp, gbc);
    }

    public static void main(String... args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new GridBagExample().createAndDisplayGUI();
            }
        });
    }
}

OUTPUT: GRIDBAGLAYOUT:

The same output can be achieved by GridLayout, if GridBagLayout is not a necessity in this case, as cited in the below example:

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

public class GridBagExample {
    private static final int SIZE = 10;
    private JButton[] buttons;

    public GridBagExample() {
        buttons = new JButton[SIZE];
    }

    private void createAndDisplayGUI() {
        JFrame frame = new JFrame("Grid Game");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        JPanel contentPane = new JPanel();
        contentPane.setLayout(new GridLayout(2, 1, 5, 5));
        contentPane.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));

        JPanel topPanel = new JPanel();
        JTextArea tArea = new JTextArea(5, 30);
        JScrollPane scroller = new JScrollPane();
        scroller.setViewportView(tArea);
        topPanel.add(scroller);

        JPanel buttonPanel = new JPanel(new GridLayout(2, 1, 5, 5));
        JPanel headerPanel = new JPanel(new GridLayout(1, 0, 5, 5));
        buttons[0] = new JButton("A");
        headerPanel.add(buttons[0]);
        buttons[1] = new JButton("B");
        headerPanel.add(buttons[1]);
        buttons[2] = new JButton("C");
        headerPanel.add(buttons[2]);
        buttons[3] = new JButton("D");
        headerPanel.add(buttons[3]);
        buttons[4] = new JButton("E");
        headerPanel.add(buttons[4]);
        buttons[5] = new JButton("F");
        headerPanel.add(buttons[5]);
        JPanel footerPanel = new JPanel(new GridLayout(1, 0, 5, 5));
        buttons[6] = new JButton("WA");
        footerPanel.add(buttons[6]);
        buttons[7] = new JButton("WB");
        footerPanel.add(buttons[7]);
        buttons[8] = new JButton("WC");
        footerPanel.add(buttons[8]);
        buttons[9] = new JButton("WD");
        footerPanel.add(buttons[9]);
        buttonPanel.add(headerPanel);
        buttonPanel.add(footerPanel);

        contentPane.add(topPanel);
        contentPane.add(buttonPanel);

        frame.setContentPane(contentPane);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    public static void main(String... args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new GridBagExample().createAndDisplayGUI();
            }
        });
    }
}

OUTPUT: GRIDLAYOUT: