编的记事本程序,有问题想请教~(在线等待)

import java.lang.*;
import java.awt.*;
import java.io.*;
import java.awt.event.*;
import java.awt.datatransfer.*;public class EditorFrame extends Frame implements ActionListener
{
TextArea textArea = new TextArea();
MenuBar menubar = new MenuBar();

Menu filemenu = new Menu("文件");
MenuItem newItem = new MenuItem("新建");
MenuItem openItem = new MenuItem("打开");
MenuItem saveItem = new MenuItem("保存");
MenuItem saveasItem = new MenuItem("另存为");
MenuItem exitItem = new MenuItem("退出");

Menu editmenu = new Menu("编辑");
MenuItem selectItem = new MenuItem("全选");
MenuItem copyItem = new MenuItem("复制");
MenuItem cutItem = new MenuItem("剪切");
MenuItem pasteItem = new MenuItem("粘贴");

Menu helpmenu = new Menu("帮助");
MenuItem aboutItem = new MenuItem("关于记事本");

String fileName = "NoName";
Toolkit toolKit = Toolkit.getDefaultToolkit();
Clipboard clipBoard = toolKit.getSystemClipboard();

private FileDialog openFileDialog
     = new FileDialog(this,"Open File",FileDialog.LOAD);
private FileDialog saveasFileDialog
     = new FileDialog(this,"Save File As",FileDialog.SAVE);

public EditorFrame()
{
setTitle("记事本");
setFont(new Font("Times New Roman",Font.PLAIN,12));
setBackground(Color.white);
setSize(300,200);

filemenu.add(newItem);
filemenu.add(openItem);
filemenu.addSeparator();
filemenu.add(saveItem);
filemenu.add(saveasItem);
filemenu.addSeparator();
filemenu.add(exitItem);
editmenu.add(selectItem);
editmenu.addSeparator();
editmenu.add(copyItem);
editmenu.add(cutItem);
editmenu.add(pasteItem);
helpmenu.add(aboutItem);

menubar.add(filemenu);
menubar.add(editmenu);
menubar.add(helpmenu);

setMenuBar(menubar);
add(textArea);
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});

newItem.addActionListener(this);
openItem.addActionListener(this);
saveItem.addActionListener(this);
saveasItem.addActionListener(this);
exitItem.addActionListener(this);
selectItem.addActionListener(this);
copyItem.addActionListener(this);
cutItem.addActionListener(this);
pasteItem.addActionListener(this);
}
public void actionPerformed(ActionEvent e)
{
Object eventSource = e.getSource();
if(eventSource == newItem)
{
textArea.setText("");
}
else if(eventSource == openItem)
{
openFileDialog.setVisible(true);
fileName = openFileDialog.getDirectory() + openFileDialog.getFile();
if(fileName != null)
{
readFile(fileName);
}
}
else if(eventSource == saveasItem)
{
saveasFileDialog.setVisible(true);
fileName = saveasFileDialog.getDirectory() + saveasFileDialog.getFile();

if(fileName != null)
{
writeFile(fileName);
}
}
else if(eventSource == selectItem)
{
textArea.selectAll();
}
else if(eventSource == copyItem)
{
String text = textArea.getSelectedText();
StringSelection selection = new StringSelection(text);
clipBoard.setContents(selection,null);
}
else if(eventSource == cutItem)
{
String text = textArea.getSelectedText();
StringSelection selection = new StringSelection(text);
clipBoard.setContents(selection,null);
textArea.replaceRange("",textArea.getSelectionStart(),textArea.getSelectionEnd());

}
else if(eventSource == pasteItem)
{
Transferable contents = clipBoard.getContents(this);
if(contents == null)
{
return;
}
String text;
text = "";
try
{
text = (String)contents.getTransferData(DataFlavor.stringFlavor);
}
catch(Exception exception)
{

}
textArea.replaceRange(text,textArea.getSelectionStart(),textArea.getSelectionEnd());

}
else if(eventSource == exitItem)
{
System.exit(0);
}
}
public void readFile(String fileName)
{
try
{
File file = new File(fileName);
FileReader readIn = new FileReader(file);
int size = (int)file.length();
int charsRead = 0;
char[] content = new char[size];
while(readIn.ready())
{
charsRead += readIn.read(content,charsRead,size-charsRead);
}
readIn.close();
textArea.setText(new String(content,0,charsRead));
}
catch(IOException e)
{
System.out.println("Error Opening file");
}
}
public void writeFile(String fileName)
{
try
{
File file = new File(fileName);
FileWriter writeOut = new FileWriter(file);
writeOut.write(textArea.getText());
writeOut.close();
}
catch(IOException e)
{
System.out.println("Error writing file");
}
}
public static void main(String[] args)
{
Frame frame = new EditorFrame();
frame.setVisible(true);
}
}
drinkant(喝酒的蚂蚁) 不是说过了吗？你不明白么？
比如：前面定义JMenu是用的"Open..."，后面比较id时为什么成了"open..."？下面的代码只改了大小写，通过了。不过还是要尽量使用常量。
比如：final String OPEN_MENU = "Open...";　以后凡是用到这个串的地方都用OPEN_MENU来代替
import java.awt.*;
import java.awt.event.*;import java.io.*;import javax.swing.*;
class newtest extends JFrame implements ActionListener {
    File file = null;
    Color color = Color.black;
    JTextPane text = new JTextPane();
    JFileChooser filechooser = new JFileChooser();
    JColorChooser jcolorchooser = new JColorChooser();
    JDialog about = new JDialog(this);
    JMenuBar menubar = new JMenuBar();
    JMenu[] menus = new JMenu[] { new JMenu("File"), new JMenu("Edit"), new JMenu("Help"), };
    JMenuItem[][] menuitems = new JMenuItem[][] {
            {
                new JMenuItem("New"), new JMenuItem("Open..."), new JMenuItem("Save..."),
                new JMenuItem("Exit")
            },
            {
                new JMenuItem("Copy"), new JMenuItem("Cut"), new JMenuItem("Paste"),
                new JMenuItem("Color...")
            },
            { new JMenuItem("About") }
        };    newtest() {
        inittextpane();
        initmenu();
        initaboutdialog();
    }    void inittextpane() {
        getContentPane().add(new JScrollPane(text));
    }    void initmenu() {
        for (int i = 0; i < menus.length; i++) {
            menubar.add(menus[i]);            for (int j = 0; j < menuitems[i].length; j++) {
                menus[i].add(menuitems[i][j]);
                menuitems[i][j].addActionListener(this);
            }
        }        this.setJMenuBar(menubar);
    }    public void actionPerformed(ActionEvent e) {
        JMenuItem mi = (JMenuItem) e.getSource();
        String id = mi.getText();        if (id.equals("New")) {
            text.setText("");
            file = null;
        } else if (id.equals("Open...")) {
            if (file != null) {
                filechooser.setSelectedFile(file);
            }            int returnVal = filechooser.showOpenDialog(newtest.this);            if (returnVal == JFileChooser.APPROVE_OPTION) {
                file = filechooser.getSelectedFile();
                openFile();
            }
        } else if (id.equals("Save...")) {
            if (file != null) {
                filechooser.setSelectedFile(file);
            }            int returnVal = filechooser.showSaveDialog(newtest.this);            if (returnVal == JFileChooser.APPROVE_OPTION) {
                file = filechooser.getSelectedFile();
                saveFile();
            }
        } else if (id.equals("Exit")) {
            System.exit(0);
        } else if (id.equals("Cut")) {
            text.cut();
        } else if (id.equals("Copy")) {
            text.copy();
        } else if (id.equals("Paste")) {
            text.paste();
        } else if (id.equals("Color...")) {
            color = JColorChooser.showDialog(this, "", color);
            text.setForeground(color);
        } else if (id.equals("About")) {
            about.setSize(100, 50);
            about.show();
        }
    }    void saveFile() {
        try {
            FileWriter fw = new FileWriter(file);
            fw.write(text.getText());
            fw.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }    void openFile() {
        try {
            FileReader fr = new FileReader(file);
            int len = (int) file.length();
            char[] buffer = new char[len];
            fr.read(buffer, 0, len);
            fr.close();
            text.setText(new String(buffer));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }    void initaboutdialog() {
        JLabel jb = new JLabel("a sample test");
        about.getContentPane().add(jb);
        about.setModal(true);
        about.setSize(100, 50);
    }
}
public class testeditapp {
    public static void main(String[] args) {
        newtest f = new newtest();
        f.setTitle("a test app");
        f.setSize(590, 400);
        f.show();
    }
}

调试易

编的记事本程序,有问题想请教~(在线等待)

解决方案 »