menudemo.java~5~

老师上课反复讲解的JAVA swing 组件事例程序

package menudemo;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Me
nuDemo implements ItemListener,ActionListener{    public MenuDemo() {
        try {
            jbInit();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    JFrame frame=new JFrame("Menu Demo");
    JTextField tf=new JTextField();

    public static void main(String args[]){
        MenuDemo menuDemo=new MenuDemo();
        menuDemo.go();
    }
    public void go(){
        JMenuBar menubar=new JMenuBar();
        frame.setJMenuBar(menubar);
        JMenu menu,submenu;
        JMenuItem menuItem;
        menu=new JMenu("File");
        menu.setMnemonic(KeyEvent.VK_F);
        menubar.add(menu);
        menuItem=new JMenuItem("Open...");
        menuItem.setMnemonic(KeyEvent.VK_O);
        menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_1,ActionEvent.ALT_MASK));
        menuItem.addActionListener(this);
        menu.add(menuItem);
        menuItem=new JMenuItem("Save",KeyEvent.VK_S);
        menuItem.addActionListener(this);
        menuItem.setEnabled(false);
        menu.add(menuItem);
        menuItem=new JMenuItem("Close");
        menuItem.setMnemonic(KeyEvent.VK_C);
        menuItem.addActionListener(this);
        menu.add(menuItem);

        menu.add(new JSeparator());
        menuItem=new JMenuItem("Exit");
        menuItem.setMnemonic(KeyEvent.VK_E);
        menuItem.addActionListener(this);
        menu.add(menuItem);

        menu=new JMenu("Option");
        menubar.add(menu);

        menu.add("Font...");

        submenu=new JMenu("Color...");
        menu.add(submenu);
        menuItem=new JMenuItem("Foreground");
        menuItem.addActionListener(this);
        menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_2,ActionEvent.ALT_MASK));

        submenu.add(menuItem);
        menuItem=new JMenuItem("Background");
        menuItem.addActionListener(this);
        menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_3,ActionEvent.ALT_MASK));

        submenu.add(menuItem);
        menu.addSeparator();
        JCheckBoxMenuItem cm=new JCheckBoxMenuItem("Always On Top");
        cm.addItemListener(this);
        menu.add(cm);
        menu.addSeparator();

        JRadioButtonMenuItem rm=new JRadioButtonMenuItem("Small",true);
        rm.addItemListener(this);
        menu.add(rm);
        ButtonGroup group=new ButtonGroup();
        group.add(rm);
        rm=new JRadioButtonMenuItem("Large");
        rm.addItemListener(this);
        menu.add(rm);
        group.add(rm);
        menu=new JMenu("Help");
        menubar.add(menu);
        menuItem=new JMenuItem("About...",new ImageIcon(""));
        menuItem.addActionListener(this);
        menu.add(menuItem);
        tf.setEditable(false);

        Container cp=frame.getContentPane();
        cp.add(tf,BorderLayout.SOUTH);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300,200);

        frame.setVisible(true);
        }
        public void itemStatedChanged(ItemEvent e){
            int state=e.getStateChange();
            JMenuItem amenuItem=(JMenuItem)e.getSource();
            String command=amenuItem.getText();
            if(state==ItemEvent.SELECTED)
                tf.setText(command+"SELECTED");
            else
                tf.setText(command+"DISELECTED");

        }
        public void actionPerformed(ActionEvent e){
            tf.setText(e.getActionCommand());
            if(e.getActionCommand()=="Exit"){
                System.exit(0);
            }
        }

    public void itemStateChanged(ItemEvent e) {
    }

    private void jbInit() throws Exception {
    }
}