gridbaglayoutdemo.java

这是一个用java编写的关于GUI应用编程的简单的样例

package chap13.demo;

/**
 * Created by IntelliJ IDEA.
 * User: Administrator
 * Date: 2008-3-4
 * Time: 0:34:31
 * File GridBagLayoutDemo.java
 */
import java.awt.*;
import javax.swing.*;

public class GridBagLayoutDemo extends JFrame{
    final static boolean shouldFill = true;
    final static boolean shouldWeightX = true;
    final static boolean RIGHT_TO_LEFT = false;

    public GridBagLayoutDemo() throws HeadlessException {
    }

    public GridBagLayoutDemo(String title) throws HeadlessException {
        super(title);
    }

    public static void addComponentsToPane(Container cpane) {
        JPanel pane=new JPanel(new GridBagLayout());
        if (RIGHT_TO_LEFT) {
            pane.setComponentOrientation(ComponentOrientation.RIGHT_TO_LEFT);
        }
        JButton button;
        pane.setLayout(new GridBagLayout());
        GridBagConstraints c = new GridBagConstraints();
        if (shouldFill) {
            //natural height, maximum width
            c.fill = GridBagConstraints.HORIZONTAL;
        }

        button = new JButton("Button 1");
        if (shouldWeightX) {
            c.weightx = 0.5;
        }
        c.gridx = 0;
        c.gridy = 0;
        pane.add(button, c);

        button = new JButton("Button 2");
        c.gridx = 1;
        c.gridy = 0;
        pane.add(button, c);

        button = new JButton("Button 3");
        c.gridx = 2;
        c.gridy = 0;
        pane.add(button, c);

        button = new JButton("Long-Named Button 4");
        c.ipady = 40;      //make this component tall
        c.weightx = 0.0;
        c.gridwidth = 3;
        c.gridx = 0;
        c.gridy = 1;
        pane.add(button, c);

        button = new JButton("5");
        c.ipady = 0;       //reset to default
        c.weighty = 1.0;   //request any extra vertical space
        c.anchor = GridBagConstraints.PAGE_END; //bottom of space
        c.insets = new Insets(10,0,0,0);  //top padding
        c.gridx = 1;       //aligned with button 2
        c.gridwidth = 2;   //2 columns wide
        c.gridy = 2;       //third row
        pane.add(button, c);
        cpane.add(pane,BorderLayout.CENTER);
    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);

        //Create and set up the window.
        GridBagLayoutDemo frame = new GridBagLayoutDemo("GridBagLayoutDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Set up the content pane.
        addComponentsToPane(frame.getContentPane());

        //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();
            }
        });
    }
}