Java GridBagLayout resizing and fixed size

Question

This is what i'm trying to achieve

------------------------| 150px |
|                       | width |
|                       |   p2  |
|                       |       |
|      Fill frame       |       |
|      p1               |       |
|                       |       |
|                       |       |
------------------------|       |
150px height            |       |
|       p3              |       |
---------------------------------

The 'Fill frame' has to scale dynamic, but the other two squares have a fixed width / height.

My code does produce this layout, but p1 is not scaling to fill up the entire frame. Could someone please tell me how to make p1 dynamic?

Thanks in advance.

This is what i have so far:

    setTitle(Rolit.TITLE);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    mainPanel = new JPanel();
    mainPanel.setLayout(new GridBagLayout());
    GridBagConstraints c = new GridBagConstraints();

//P1    FILL P1 WITH 64 BUTTONS
    p1 = new JPanel();
    p1.setLayout(new GridLayout(8, 8));

    p1.setMinimumSize(new Dimension(600, 600));
    p1.setMaximumSize(new Dimension(600, 600));
    p1.setPreferredSize(new Dimension(600, 600));

    for(int y = 0; y < 8; y++){
        for(int x = 0; x < 8; x++){
            JButton btn = new JButton(x + " , " + y);
            p1.add(btn);
        }
    }

//P2    FILL P2 WITH 4 BUTTONS
    p2 = new JPanel();
    p2.setLayout(new GridLayout(4, 1));
    p2.setMinimumSize(new Dimension(150, 100));
    p2.setMaximumSize(new Dimension(150, 100));
    p2.setPreferredSize(new Dimension(150, 100));

    for(int i = 0; i < 4; i++){
        p2.add(new JButton("Button"));
    }

//P3
    p3 = new JPanel();
    p3.setMinimumSize(new Dimension(100, 150));
    p3.setMaximumSize(new Dimension(100, 150));
    p3.setPreferredSize(new Dimension(100, 150));
    p3.setBackground(Color.BLUE);


//ADD ALL TO mainPanel

    c.gridx = 0;
    c.gridy = 0;
    c.fill = GridBagConstraints.BOTH; 
    mainPanel.add(p1, c);        

    c.gridx = 1;
    c.gridheight = 2;  
    c.fill = GridBagConstraints.VERTICAL;
    mainPanel.add(p2, c);

    c.gridx = 0;
    c.gridy = 1;
    c.gridheight = 1;        
    c.gridwidth = 2;
    c.fill = GridBagConstraints.HORIZONTAL;
    mainPanel.add(p3, c);

    setContentPane(mainPanel);
    pack();
    setLocationRelativeTo(null);
    setVisible(true);

Answer 1

You need to supply weightx and weighty values with the GridBagConstraints which affect how the individual components react to changes in the size the parent container and how much "weight" the take up within the given cell

Take a look at How to use GridBagLayout for more details

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class TestGridBagLayout {

    public static void main(String[] args) {
        new TestGridBagLayout();
    }

    private JPanel mainPanel;
    private JPanel p1;
    private JPanel p2;
    private JPanel p3;

    public TestGridBagLayout() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                mainPanel = new JPanel();
                mainPanel.setLayout(new GridBagLayout());
                GridBagConstraints c = new GridBagConstraints();

                //P1    FILL P1 WITH 64 BUTTONS
                p1 = new JPanel();
                p1.setLayout(new GridLayout(8, 8));

                p1.setMinimumSize(new Dimension(600, 600));
                p1.setMaximumSize(new Dimension(600, 600));
                p1.setPreferredSize(new Dimension(600, 600));

                for (int y = 0; y < 8; y++) {
                    for (int x = 0; x < 8; x++) {
                        JButton btn = new JButton(x + " , " + y);
                        p1.add(btn);
                    }
                }

                //P2    FILL P2 WITH 4 BUTTONS
                p2 = new JPanel();
                p2.setLayout(new GridLayout(4, 1));
                p2.setMinimumSize(new Dimension(150, 100));
                p2.setMaximumSize(new Dimension(150, 100));
                p2.setPreferredSize(new Dimension(150, 100));

                for (int i = 0; i < 4; i++) {
                    p2.add(new JButton("Button"));
                }

                //P3
                p3 = new JPanel();
                p3.setMinimumSize(new Dimension(100, 150));
                p3.setMaximumSize(new Dimension(100, 150));
                p3.setPreferredSize(new Dimension(100, 150));
                p3.setBackground(Color.BLUE);

                //ADD ALL TO mainPanel
                c.gridx = 0;
                c.gridy = 0;
                c.fill = GridBagConstraints.BOTH;
                c.weightx = 1;
                c.weighty = 1;
                mainPanel.add(p1, c);

                c.gridx = 1;
                c.gridheight = 2;
                c.weighty = 1;
                c.weightx = 0;
                c.fill = GridBagConstraints.VERTICAL;
                mainPanel.add(p2, c);

                c.gridx = 0;
                c.gridy = 1;
                c.gridheight = 1;
                c.gridwidth = 2;
                c.fill = GridBagConstraints.HORIZONTAL;
                c.weighty = 0;
                c.weightx = 1;
                mainPanel.add(p3, c);

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(mainPanel);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

}