Remove huge gaps between check boxes on panel

Question

Its pretty basic UI, but I cannot setup the JCheckBox buttons so that they are placed immediately after one another (vertically) without any spacing. How would I reduce the spacing seen below?

JPanel debugDrawPanel = new JPanel(new GridLayout(0,1));         
JPanel eastPanel = new JPanel(new GridLayout(1,0));
JTabbedPane tab = new JTabbedPane();

click = new ClickPanel(this);

setSettings(new Settings());

for (Setting setting: getSettings().getAll()){

    JCheckBox checkBox = new JCheckBox(setting.name);
    checkBox.setName(setting.name);
    checkBox.addItemListener(new CheckBoxItemListener(this));
    debugDrawPanel.add(checkBox);
}

tab.addTab("Object Parameters", click);
tab.addTab("Debug Draw", debugDrawPanel);

Answer 1

It appears that the minimum vertical size is being set by the content of another tab. One way to get around that is to put the GridLayout in the PAGE_START of a BorderLayout before putting the panel with border layout into the tabbed pane.

• The panel with GridLayout has an orange BG.
• The panel with BorderLayout has a yellow BG.

---

import java.awt.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.swing.border.EmptyBorder;

public class TopAlignedComponents {

    private JComponent ui = null;

    TopAlignedComponents() {
        initUI();
    }

    public void initUI() {
        if (ui!=null) return;

        ui = new JPanel(new BorderLayout(4,4));
        ui.setBorder(new EmptyBorder(4,4,4,4));

        JTabbedPane tb = new JTabbedPane();
        ui.add(tb);
        Image spacer = new BufferedImage(300, 100, BufferedImage.TYPE_INT_RGB);
        tb.addTab("Spacer", new JLabel(new ImageIcon(spacer)));

        String[] labels = {"Shapes", "Joints", "AABBs"};
        JPanel checkPanel = new JPanel(new GridLayout(0, 1, 4, 4));
        checkPanel.setBackground(Color.ORANGE);
        for (String label : labels) {
            checkPanel.add(new JCheckBox(label));
        }

        JPanel checkConstrain = new JPanel(new BorderLayout());
        checkConstrain.setBackground(Color.YELLOW);
        checkConstrain.add(checkPanel, BorderLayout.PAGE_START);

        tb.addTab("Check", checkConstrain);
    }

    public JComponent getUI() {
        return ui;
    }

    public static void main(String[] args) {
        Runnable r = new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (Exception useDefault) {
                }
                TopAlignedComponents o = new TopAlignedComponents();

                JFrame f = new JFrame("Top Aligned Components");
                f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                f.setLocationByPlatform(true);

                f.setContentPane(o.getUI());
                f.pack();
                f.setMinimumSize(f.getSize());

                f.setVisible(true);
            }
        };
        SwingUtilities.invokeLater(r);
    }
}

Answer 2

If i remember correctly, its because of your layout!

GridLayout divides your windowsize into equal parts, so i think you should either unset your windows size and use pack() or you could switch to a different layout.

( I assume your window's size is or minimum-size is set somewhere )