import java.awt.*; import java.awt.event.*; import javax.swing.*; public class BoxLayoutDemo { protected static int NUM_COMPONENTS = 3; protected static float[] xAlignment = {Component.LEFT_ALIGNMENT, Component.CENTER_ALIGNMENT, Component.RIGHT_ALIGNMENT}; protected static float[] hue = {0.0f, 0.33f, 0.67f}; protected static boolean restrictSize = true; protected static boolean sizeIsRandom = false; protected static BLDComponent[] bldComponent = new BLDComponent[NUM_COMPONENTS]; public static void main(String[] args) { final JPanel panel = new JPanel(); panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS)); /* Create the rectangles. */ int shortSideSize = 15; for (int i = 0; i < BoxLayoutDemo.NUM_COMPONENTS; i++) { if (sizeIsRandom) { shortSideSize = (int)(30.0 * Math.random()) + 30; } else { shortSideSize += 10; } bldComponent[i] = new BLDComponent(xAlignment[i], hue[i], shortSideSize, restrictSize, sizeIsRandom, String.valueOf(i)); panel.add(bldComponent[i]); } /* Create the instructions. */ JLabel label = new JLabel("Click a rectangle to change its X alignment."); JCheckBox cb = new JCheckBox("Restrict maximum rectangle size."); cb.setSelected(restrictSize); cb.addItemListener(new ItemListener() { public void itemStateChanged(ItemEvent e) { if (e.getStateChange() == ItemEvent.SELECTED) { restrictSize = true; } else { restrictSize = false; } notifyBLDComponents(); } }); WindowListener l = new WindowAdapter() { public void windowClosing(WindowEvent e) {System.exit(0);} }; JFrame f = new JFrame("BoxLayoutDemo"); Container contentPane = f.getContentPane(); contentPane.add("Center", panel); panel.setBorder(BorderFactory.createLineBorder(Color.red)); Box box = Box.createVerticalBox(); box.add(label); box.add(cb); contentPane.add("South", box); f.addWindowListener(l); f.pack(); f.show(); } static public void notifyBLDComponents() { for (int i = 0; i < NUM_COMPONENTS; i++) { bldComponent[i].setSizeRestriction(restrictSize); } bldComponent[0].revalidate(); } }