Java Swing How to - Layout buttons in single line with same width using BoxLayout

Question

We would like to know how to layout buttons in single line with same width using BoxLayout.

Answer

import java.awt.Component;
import java.awt.Dimension;
//w ww. jav a  2 s.c o  m
import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.border.EmptyBorder;

public class Main extends JFrame {
  public Main() {
    Box box = Box.createHorizontalBox();
    box.setBorder(new EmptyBorder(5, 5, 5, 5));
    Dimension size = new Dimension(100, 25);

    box.add(createButton("Button1", size));
    box.add(createStrut());
    box.add(createButton("Button2", size));
    box.add(createStrut());
    box.add(createButton("Button3", size));
    box.add(createStrut());
    box.add(createButton("Button4", size));

    add(box);
  }

  private JButton createButton(String text, Dimension size) {
    JButton button = new JButton(text);
    button.setPreferredSize(size);
    button.setMinimumSize(size);
    button.setMaximumSize(size);
    return button;
  }

  private Component createStrut() {
    JComponent component = (JComponent) Box.createHorizontalStrut(5);
    component.setMinimumSize(new Dimension(0, 0));
    component.setMaximumSize(new Dimension(Short.MAX_VALUE, Short.MAX_VALUE));
    return component;
  }

  public static void main(String[] args) {
    Main frame = new Main();
    frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
    frame.pack();
    frame.setVisible(true);
  }
}