Having a Left and Right Aligned Label inside a JCheckBox

Question

I'll start with what I want then go from there:

+------------------------------------------+
|[] jCheckBox                       jLabel |
+------------------------------------------+

Basically I would like to have a JCheckBox with 2 segments of text, 1 left aligned and 1 right aligned. I would like the entire box to be clickable and act exactly like a JCheckBox(As in if I press my mouse down it highlights the box ect.).

Now I have tried:

Using HTML inside the text box, with a table along the lines of: <html><table width=100%><tr width=100%><td>Left Text</td><td align=right>Right Text</td></tr></table>. This produces [] Left TextRightText without any visual alignment.
Adding both the JCheckBox and the JLabel to a panel, however this would require me to implement all the mouse events and call the correct respective methods on the JCheckBox. I put this aside - however I am willing to reconsider if this is the only option
Adding the JLabel to the JCheckBox
- Firstly this caused the JCheckBox to decide to change the font, so that had to be 'adjusted'
- Secondly, the baselines were off by 1 or 2 pixels, This was fixed by implementing a LayoutManager that placed the JLabel on the baseline.
- Thirdly, the JLabel overlapped with the JCheckBox text so I ad to adjust my layout manager, however the JCheckBox did not give a correct result from getPreferedSize()(of [1,1]).

So, basically my question is: How should I implement this?

So, if I understand correctly, you want this composite panel to behave exactly as the checkbox inside, right? — Alessandro Santini, Dec 20 '12 at 09:31

score 4 · Accepted Answer · edited May 23 '17 at 12:08

create parent JLabel, JLabel haven't implemented any LayoutManager, then to set there proper LayoutManager, I think that GridLayout (with 2 segments of text, 1 left aligned and 1 right aligned)
add there two JLabels with proper alignment (JLabel.setHorizontalAlignment(javax.swing.SwingConstants.XXX);)
put together JCheckBox with parent JLabel (JLabel.setLabelFor(JCheckBox);)
the same way for MultiIcon in the JLabel

score 2 · Answer 2 · answered Dec 20 '12 at 10:00

This is how I managed to implement it using a JCheckBox as a parent class. This is missing methods for setting the label's text and color.

package mock.dlect;

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.LayoutManager;
import javax.swing.Icon;
import javax.swing.JCheckBox;
import javax.swing.JLabel;

public class LeftRightCheck extends JCheckBox {

    private final static JCheckBox DEFAULT_CHECK_BOX = new JCheckBox();
    private final JLabel rightLabel;

    public LeftRightCheck(String leftText, String rightText, Icon icon,
            boolean selected) {
        super(leftText, icon, selected);
        rightLabel = new JLabel(rightText, TRAILING);
        // TODO figure out how to make the font work right on OSX
        this.setLayout(new BaseLineSingleElementLayoutManager(10));
        this.add(rightLabel);
    }

    @Override
    public final void setFont(Font font) {
        font = font.deriveFont(DEFAULT_CHECK_BOX.getFont().getSize2D());
        super.setFont(font);
        if (rightLabel != null) {
            rightLabel.setFont(font);
        }
    }

    private class BaseLineSingleElementLayoutManager implements LayoutManager {

        private int hgap;
        private Component component;

        public BaseLineSingleElementLayoutManager(int hgap) {
            this.hgap = hgap;
        }

        @Override
        public void addLayoutComponent(String name, Component comp) {
            // Do Nothing
        }

        @Override
        public void removeLayoutComponent(Component comp) {
            // Do Nothing
        }

        @Override
        public Dimension preferredLayoutSize(Container parent) {
            if (parent != null && parent instanceof JCheckBox) {
                JCheckBox cc = (JCheckBox) parent;
                // These 2 lines will add the size of the checkbox to the
                // preferred size
                Dimension parentSize = DEFAULT_CHECK_BOX.getPreferredSize();
                parentSize.width += cc.getFontMetrics(cc.getFont()).
                        stringWidth(cc.getText()) + hgap;
                if (checkComponent(cc)) {
                    Dimension childSize = this.component.getPreferredSize();
                    parentSize.height = Math.max(parentSize.height,
                            childSize.height);
                    parentSize.width += childSize.width;
                }
                return parentSize;
            }
            return new Dimension();
        }

        @Override
        public Dimension minimumLayoutSize(Container parent) {
            return preferredLayoutSize(parent);
        }

        @Override
        public void layoutContainer(Container parent) {
            if (!checkComponent(parent)) {
                return;
            }
            this.component.setSize(parent.getSize());
            this.component.setLocation(0, getBaseline(parent)
                    - getBaseline(this.component));
        }

        private int getBaseline(Component c) {
            return c.getBaseline(c.getWidth(), c.getHeight());
        }

        protected boolean checkComponent(Container parent) {
            if (parent == null) {
                return false;
            } else if (parent.getComponentCount() >= 1
                    && parent.getComponent(0).isVisible()) {
                this.component = parent.getComponent(0);
                return true;
            } else {
                return false;
            }
        }
    }
}

score 1 · Answer 3 · answered Dec 20 '12 at 09:48

public class LeesCheckbox extends JPanel 
{
    private JCheckBox checkbox;

    public LeesCheckbox(String leftText, String rightText){
        super(new BorderLayout());
        checkbox = new JCheckBox(leftText);
        add(checkbox, BorderLayout.WEST);
        add(new JLabel(rightText), BorderLayout.EAST);
        setBorder(BorderFactory.createLineBorder(Color.BLACK, 1));
        addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e) {
                checkbox.setSelected(!checkbox.isSelected());
            }
        });
    }

    public JCheckBox getCheckbox() {
        return checkbox;
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        Box content = new Box(BoxLayout.Y_AXIS);
        content.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
        LeesCheckbox box = new LeesCheckbox("Left text", "Right text");
        box.setMaximumSize(new Dimension(Integer.MAX_VALUE, 25));
        content.add(box);
        content.add(Box.createVerticalGlue());

        frame.setContentPane(content);
        frame.setSize(300, 300);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

}

Having a Left and Right Aligned Label inside a JCheckBox

3 Answers3