Question

I am making an application for which I am using a BoxLayout. As you can see in the following picture, when the title string is short, it’s perfect. But as the string gets longer, the JLabel gets more and more misaligned.

Here’s some code that is related to the problem:

JPanel centerPanel = new JPanel();
centerPanel.setLayout(new BoxLayout(centerPanel, BoxLayout.PAGE_AXIS));
frame.add(centerPanel, BorderLayout.CENTER);
//...
JLabel l = new JLabel(/*...*/);
l.setHorizontalAlignment(SwingConstants.CENTER); //I tried removing and adding
                                                 //this but nothing changed
centerPanel.add(l);

Is there something obvious I am missing? Google isn’t being helpful with this problem.

In case it’s important, the country-label-progress-bar things are just JPanels with FlowLayouts.

SSCCE:

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;

public class SSCCE {

    public static void main(String[] args) {
        final JFrame f = new JFrame("SSCCE");
        JPanel p = new JPanel();
        p.setLayout(new BoxLayout(p, BoxLayout.PAGE_AXIS));
        final JLabel[] titles = new JLabel[5];
        JPanel[] smallPanels = new JPanel[titles.length];
        for (int i = 0; i < smallPanels.length; i ++) {
            titles[i] = new JLabel(Math.random() < 0.5 ? "foo" : "bar");
            p.add(titles[i]);
            smallPanels[i] = new JPanel();
            smallPanels[i].add(new JLabel("foobar"));
            smallPanels[i].add(new JProgressBar());
            p.add(smallPanels[i]);
        }
        f.add(p, BorderLayout.CENTER);
        final JTextField tf = new JTextField("foobar");
        tf.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                titles[2].setText(tf.getText());
                f.repaint();
            }
        });
        f.add(tf, BorderLayout.NORTH);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setSize(600, 600);
        f.setVisible(true);
    }

}

To operate the SSCCE, type something in the text field and press enter.

Answer 1

• BoxLayout accepting Min, Max and PreferredSize, childs could be resizable from Min to MaxSize

• FlowLayout accepting only PreferredSize, rest (Min, MaxSize) is ignored by this LayoutManager, childs aren’t resizable

• these XxxSize are calculated from PreferredSize came from childs placed into container (JPanel in this case)

• (your question) for better help sooner post an SSCCE, short, runnable, compilable, just about your issue