Java GUI之FileDialog实现记事本

public class FileDialogDemo implements ActionListener {
private Frame f;
private FileDialog fload;
private FileDialog fsave;
private TextArea t;
private String file = "";

public static void main(String[] args) {
new FileDialogDemo().init();
}

public void init() {
f = new Frame("My Notepad");
MenuBar mb = new MenuBar();
Menu file = new Menu("文件");
Menu help = new Menu("帮助");
MenuItem open = new MenuItem("打开");
MenuItem save = new MenuItem("保存");
MenuItem saveAs = new MenuItem("另存为");
file.add(open);
file.add(save);
file.add(saveAs);
mb.add(file);
mb.add(help);
f.setMenuBar(mb);
t = new TextArea();
f.add(t, "Center");
open.addActionListener(this);
save.addActionListener(this);
saveAs.addActionListener(this);
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
f.setSize(400, 200);
f.setLocation(450, 200);
f.setVisible(true);
fload = new FileDialog(f, "打开文件", FileDialog.LOAD);
fsave = new FileDialog(f, "保存文件", FileDialog.SAVE);
}

public void actionPerformed(ActionEvent e) {
String s = e.getActionCommand();
if (s.equals("打开")) {
fload.setVisible(true);
String d = fload.getDirectory();
String f = fload.getFile();
if ((d != null) && (f != null)) {
file = d + f;
loadFile();
}
} else if (s.equals("保存")) {
if ((file == null) || file.equals("")) {
this.saveFileAs();
} else {
this.saveFile();
}
} else if (s.equalsIgnoreCase("另存为")) {
this.saveFileAs();
}
}

public void loadFile() {
t.setText("");
t.setFont(new Font("隶书", Font.ITALIC, 20));
t.
4000
setForeground(Color.red);
f.setTitle("My Notepad-" + file);
try {
BufferedReader br = new BufferedReader(new FileReader(file));
String s = br.readLine();
while (s != null) {
t.append(s + "\n");
System.out.print(s + "\n");
s = br.readLine();
}
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}

public void saveFile() {
String c = t.getText();
try {
PrintWriter pw = new PrintWriter(new FileWriter(file));
pw.println(c);
pw.close();
} catch (IOException e) {
e.printStackTrace();
}
}

public void saveFileAs() {
fsave.setVisible(true);
String d = fload.getDirectory();
String fd = fload.getFile();
if ((d != null) && (f != null)) {
file = d + fd;
this.saveFile();
f.setTitle("My Notepad-" + file);
}
}
}