问嵌套类的UIManager.setLookAndFeel

EN

import java.awt.Dimension;

import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

/**
 * Class to demonstrate UIManager.setLookAndFeel issue.
 */
public class Test {

    /**
     * Main program.
     * @param args
     */
    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new Test();
            }
        });
    }

    /**
     * Constructor.
     */
    public Test() {
        try {
            UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName());
        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException
                | UnsupportedLookAndFeelException e) {
            e.printStackTrace();
        }

        createGUI();
    }

    /**
     * Set up the JFrame and add the main JPanel.
     */
    public void createGUI() {
        JFrame frame = new JFrame("Test");

        frame.add(new MainPanel(800, 600));

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        frame.pack();
        frame.setLocationRelativeTo(null);
    }

    /**
     * Class for the main panel that will hold all other components.
     */
    class MainPanel extends JPanel {

        private final int width;
        private final int height;

        /**
         * Serialize/save.
         */
        private static final long serialVersionUID = -3727866499459986351L;

        /**
         * Constructor.
         */
        public MainPanel(int w, int h) {
            this.width = w;
            this.height = h;

            // ISSUE the chooser does not have the look and feel of my OS
            // unless I set the look and feel in this constructor
            JFileChooser chooser = new JFileChooser();
            this.add(chooser);
        }

        /**
         * 
         */
        public Dimension getPreferredSize() {
            return new Dimension(width, height);
        }
    }

}