关于Swing 包的一个简单应用

点击按钮出发label计数点击次数的小程序

package com.ysh.job.frame;

import javax.swing.*;          

import java.awt.*;

import java.awt.event.*;

public class hello implements ActionListener {

    private static String labelPrefix = "Number of button clicks: ";

    private int numClicks = 0;

    final JLabel label = new JLabel(labelPrefix + "0    ");

    //Specify the look and feel to use.  Valid values:

    //null (use the default), "Metal", "System", "Motif", "GTK+"

    final static String LOOKANDFEEL = "System";

    public Component createComponents() {

        JButton button = new JButton("I'm a Swing button!");

        button.setMnemonic(KeyEvent.VK_I);

        button.addActionListener(this);

        label.setLabelFor(button);

        /*

         * An easy way to put space between a top-level container

         * and its contents is to put the contents in a JPanel

         * that has an "empty" border.

         */

        JPanel pane = new JPanel(new GridLayout(0, 1));

        pane.add(button);

        pane.add(label);

        pane.setBorder(BorderFactory.createEmptyBorder(

                                        30, //top

                                        30, //left

                                        10, //bottom

                                        30) //right

                                        );

        return pane;

    }

    public void actionPerformed(ActionEvent e) {

        numClicks++;

        label.setText(labelPrefix + numClicks);

    }

    private static void initLookAndFeel() {

        String lookAndFeel = null;

        if (LOOKANDFEEL != null) {

            if (LOOKANDFEEL.equals("Metal")) {

                lookAndFeel = UIManager.getCrossPlatformLookAndFeelClassName();

            } else if (LOOKANDFEEL.equals("System")) {

                lookAndFeel = UIManager.getSystemLookAndFeelClassName();

            } else if (LOOKANDFEEL.equals("Motif")) {

                lookAndFeel = "com.sun.java.swing.plaf.motif.MotifLookAndFeel";

            } else if (LOOKANDFEEL.equals("GTK+")) { //new in 1.4.2

                lookAndFeel = "com.sun.java.swing.plaf.gtk.GTKLookAndFeel";

            } else {

                System.err.println("Unexpected value of LOOKANDFEEL specified: "

                                   + LOOKANDFEEL);

                lookAndFeel = UIManager.getCrossPlatformLookAndFeelClassName();

            }

            try {

                UIManager.setLookAndFeel(lookAndFeel);

            } catch (ClassNotFoundException e) {

                System.err.println("Couldn't find class for specified look and feel:"

                                   + lookAndFeel);

                System.err.println("Did you include the L&F library in the class path?");

                System.err.println("Using the default look and feel.");

            } catch (UnsupportedLookAndFeelException e) {

                System.err.println("Can't use the specified look and feel ("

                                   + lookAndFeel

                                   + ") on this platform.");

                System.err.println("Using the default look and feel.");

            } catch (Exception e) {

                System.err.println("Couldn't get specified look and feel ("

                                   + lookAndFeel

                                   + "), for some reason.");

                System.err.println("Using the default look and feel.");

                e.printStackTrace();

            }

        }

    }

    /**

     * Create the GUI and show it.  For thread safety,

     * this method should be invoked from the

     * event-dispatching thread.

     */

    private static void createAndShowGUI() {

        //Set the look and feel.---设置外观，可以忽略

        initLookAndFeel();

        //Make sure we have nice window decorations.

    //设置为false的话，即为不改变外观

        JFrame.setDefaultLookAndFeelDecorated(true);

        //Create and set up the window.

        JFrame frame = new JFrame("SwingApplication");

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        hello app = new hello();

        Component contents = app.createComponents();

        frame.getContentPane().add(contents, BorderLayout.CENTER);

        //Display the window.

        frame.pack();

        frame.setVisible(true);

    }

    public static void main(String[] args) {

        //Schedule a job for the event-dispatching thread:

        //creating and showing this application's GUI.

        javax.swing.SwingUtilities.invokeLater(new Runnable() {

            public void run() {

                createAndShowGUI();

            }

        });

    }

}