simpletexteditor.java

各种关于JAVA的初级编程

import javax.swing.*; 
import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class SimpleTextEditor extends JFrame 
    implements ActionListener
{
    private JMenuBar mBar = new JMenuBar();
    private JMenu fileMenu, editMenu, cutsMenu;
    private JMenuItem cutItem, copyItem, pasteItem, selectItem;
    private JMenuItem recentcutItem;
    private JMenuItem quitItem, openItem, saveItem;
    private JTextArea display = new JTextArea();
    private String scratchPad = " ";
    private Vector recentCuts = new Vector();
    
    public SimpleTextEditor()
    {
        super("Simple Text Editor");
        this.getContentPane().setLayout(new BorderLayout());
        this.getContentPane().add("Center", display);
        this.getContentPane().add(new JScrollPane(display));
        display.setLineWrap(true);
        this.setJMenuBar(mBar);
        initFileMenu();
        initEditMenu();
    }
    
    private void initEditMenu()
    {
        editMenu = new JMenu("Edit");
        mBar.add(editMenu);
        cutItem = new JMenuItem("Cut");
        cutItem.addActionListener(this);
        editMenu.add(cutItem);
        copyItem = new JMenuItem("Copy");
        copyItem.addActionListener(this);
        editMenu.add(copyItem);
        pasteItem = new JMenuItem("Paste");
        pasteItem.addActionListener(this);
        editMenu.add(pasteItem);
        editMenu.addSeparator();
        selectItem = new JMenuItem("Select All");
        selectItem.addActionListener(this);
        editMenu.add(selectItem);
        editMenu.addSeparator();
        cutsMenu = new JMenu("Recent Cuts");
        editMenu.add(cutsMenu);
    }
    
    private void initFileMenu()
    {
        fileMenu = new JMenu("File");
        mBar.add(fileMenu);
        openItem = new JMenuItem("Open");
        openItem.addActionListener(this);
        openItem.setEnabled(false);
        fileMenu.add(openItem);
        saveItem = new JMenuItem("Save");
        saveItem.addActionListener(this);
        saveItem.setEnabled(false);
        fileMenu.add(saveItem);
        fileMenu.addSeparator();
        quitItem = new JMenuItem("Quit");
        quitItem.addActionListener(this);
        fileMenu.add(quitItem);
    }
    
    public void actionPerformed(ActionEvent e)
    {
        JMenuItem m = (JMenuItem)e.getSource();
        if(m == quitItem)
        {
            dispose();
            System.exit(0);
        }
        else if (m == cutItem)
        {
            scratchPad = display.getSelectedText();
            display.replaceRange("",
                display.getSelectionStart(),
                display.getSelectionEnd());
            addRecentCut(scratchPad);
        }
        else if (m == copyItem)
        {
            scratchPad = display.getSelectedText();
        }
        else if (m == pasteItem)
        {
            display.insert(scratchPad,display.getCaretPosition());
        }
        else if (m == selectItem)
        {
            display.selectAll();
        }
        else
        {
            JMenuItem item = (JMenuItem)e.getSource();
            scratchPad = item.getActionCommand();
        }
    }
    
    private void addRecentCut(String cut)
    {
        recentCuts.insertElementAt(cut,0);
        cutsMenu.removeAll();
        for(int i=0; i<recentCuts.size(); i++)
        {
            JMenuItem item = new JMenuItem(
                (String)recentCuts.elementAt(i));
            cutsMenu.add(item);
            item.addActionListener(this);
        }
    }
   
    
    public static void main(String args[])
    {
        SimpleTextEditor f = new SimpleTextEditor();
        f.setSize(300,200);
        f.setVisible(true);
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent we)  {
                System.exit(0);
            }
        });
    }
}