Left- and right-justifying with dot leaders in JLabel and JButton

Question

Hi,
I am developing checklists using JLabel and JButton components and want to finish up with the text in each component looking something like the following (each line is a separate button/label):
ACTION No1............................RESPONSE No1
ACTION No2............................RESPONSE No2
ACTION No3............................RESPONSE No3
The idea is to have the �Action� text left-justified and the �Response� text right-justified with dot-leaders as shown.
Each text line will be put into its own fixed length label or button.
I plan to construct a string from text blocks �ACTION No1� and �RESPONSE No1� and add the calculated, exact no of dots in between to fill the space.
The text font can be fixed (e.g. Courier) or proportional (e.g. Arial).
My question is how to calculate the number of dots to add to fill the space for different fonts and font sizes.
I think that using FontMetrics could provide some help but am not sure how this would work.
Can anyone help.
Many tks
John

Answer 1

Hi,
I've developed your suggested code further to enable selected JLabels to be toggled visible(true/false) by pressing a JButton.
I'd like however that when a label is made invisible that the rest of the labels/buttons move up to fill the space left by the now invisible label and vice versa.
How do I do this, can you enlighten me on a solution?
Modified code included below. Not very elegant but serves to illustrate the point in question and only makes the label invisible.
Many tks
John
package componentwierd;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ComponentWierd extends JFrame implements ComponentListener, ActionListener {
    boolean isVisible = true;
    JLabel label2 = new JLabel();
    public ComponentWierd() {
        getContentPane().setLayout( new GridLayout(0, 1) );
        // Using my original suggestion
        JLabel label = new JLabel();
        label.setLayout(new BorderLayout());
        label.add(createWierdComponent());
        getContentPane().add(label);
        JButton button = new JButton();
        button.setLayout(new BorderLayout());
        button.add(createWierdComponent());
        button.addActionListener(this);
        getContentPane().add(button);
        // Using Font Metrics
        // JLabel label2 = new JLabel("Label2 West...Label2 East");
        label2.setText("Label2 West...Label2 East");
        label2.addComponentListener( this );
        getContentPane().add(label2);
        JButton button2 = new JButton("Button2 West...Button2 East");
        System.out.println(button2.getIconTextGap());
        button2.addComponentListener( this );
        button2.setVisible(true);
        getContentPane().add(button2);
    public void actionPerformed(ActionEvent e) {
        if (isVisible == true) {
            isVisible = false;
            label2.setVisible(false);
        } else if (isVisible == false) {
            isVisible = true;
            label2.setVisible(true);
    private JComponent createWierdComponent() {
        JPanel panel = new JPanel(new BorderLayout());
        panel.setOpaque( false );
        panel.add(new JLabel("Label WEST"), BorderLayout.WEST);
        panel.add(new JLabel("..............................................."));
        panel.add(new JLabel("Label EAST"), BorderLayout.EAST);
        return panel;
    public void componentResized(ComponentEvent e) {
        if (e.getComponent() instanceof JLabel) {
            JLabel component = (JLabel)e.getComponent();
            String text = component.getText();
            String fitText = fitText(component, text);
            component.setText( fitText );
        if (e.getComponent() instanceof JButton) {
            JButton component = (JButton)e.getComponent();
            String text = component.getText();
            String fitText = fitText(component, text);
            component.setText( fitText );
    private String fitText(JComponent component, String text) {
        // Calculate the total width for painting the text
        // (Not sure why I need the -8)
        Insets insets = component.getInsets();
        int availableWidth = getWidth() - insets.left - insets.right - 8;
        // Calculate the minimum width our text will take
        String start = text.substring(0, text.indexOf("."));
        String middle = "...";
        String end = text.substring(text.lastIndexOf(".") + 1);
        FontMetrics fm = getFontMetrics( component.getFont() );
        int startWidth = fm.stringWidth( start );
        int middleWidth = fm.stringWidth( middle );
        int endWidth = fm.stringWidth( end );
        int minimumWidth = startWidth + middleWidth + endWidth;
        // Add dots to fill out the extra space
        StringBuffer buffer = new StringBuffer(start);
        buffer.append(middle);
        if (minimumWidth < availableWidth) {
            String dot = ".";
            int dotWidth = fm.stringWidth( dot );
            int dots = (availableWidth - minimumWidth) / dotWidth;
            for (int i = 0; i < dots; i++) {
                buffer.append( dot );
        buffer.append(end);
        String result = buffer.toString();
        return result;
    public void componentHidden(ComponentEvent e) {}
    public void componentMoved(ComponentEvent e) {}
    public void componentShown(ComponentEvent e) {}
    public static void main(String[] args) {
        ComponentWierd frame = new ComponentWierd();
        frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
        frame.setSize(200, 200);
        frame.setLocationRelativeTo( null );
        frame.setVisible(true);
}