Java初学者：请帮助我这几天一直在努力，我的大脑已经死了。我创建了一个 java 程序（在 eclipse 中），它有 3 个菜单：文件、编辑、帮助，一旦单击文件，它就会显示 4menuBar：'new、open、save、save as & exit。
在帮助菜单上有一个菜单栏，上面写着“关于 javaEdit” 我的所有菜单栏都可以工作，除了保存、另存为和“关于 javaEdit” 我需要一些代码或一个清晰的分步说明，以便虚拟人了解如何保存和另存为工作。
保存应该保存新创建的文件或编辑过的文件，最后我可能会喜欢“关于 JavaEdit”，以便在单击后显示“谢谢，这是 java”之类的消息。我可能喜欢类似的东西
private void doSave(){code here}
和
private void doSaveAs (){
因为我在 if else if 语句中有这些项目。
java - 如何在java中创建保存新创建文件或编辑文件的保存/另存为对话框？
以下是我的完整代码：
import java.awt.*;
import java.awt.event
import java.io.*;
public class JavaEdit extends Frame implements ActionListener {
String clipBoard;
String fileName;
TextArea text;
MenuItem newMI, openMI, saveMI, saveAsMI, exitMI;
MenuItem selectAllMI, cutMI, copyMI, deleteMI, pasteMI;
MenuItem aboutJavaEditMI;
/**
* Constructor
*/
public JavaEdit() {
super("JavaEdit"); // set frame title
setLayout(new BorderLayout()); // set layout
// create menu bar
MenuBar menubar = new MenuBar();
setMenuBar(menubar);
// create file menu
Menu fileMenu = new Menu("File");
menubar.add(fileMenu);
newMI = fileMenu.add(new MenuItem("New"));
newMI.addActionListener(this);
openMI = fileMenu.add(new MenuItem("Open"));
openMI.addActionListener(this);
fileMenu.addSeparator();
saveMI = fileMenu.add(new MenuItem("Save"));
saveAsMI = fileMenu.add(new MenuItem("Save As ..."));
fileMenu.addSeparator();
exitMI = fileMenu.add(new MenuItem("Exit"));
exitMI.addActionListener(this);
// create edit menu
Menu editMenu = new Menu("Edit");
menubar.add(editMenu);
selectAllMI = editMenu.add(new MenuItem("Select all"));
selectAllMI.addActionListener(this);
cutMI = editMenu.add(new MenuItem("Cut"));
cutMI.addActionListener(this);
copyMI = editMenu.add(new MenuItem("Copy"));
copyMI.addActionListener(this);
pasteMI = editMenu.add(new MenuItem("Paste"));
pasteMI.addActionListener(this);
deleteMI = editMenu.add(new MenuItem("Delete"));
deleteMI.addActionListener(this);
// create help menu
Menu helpMenu = new Menu("Help");
menubar.add(helpMenu);
aboutJavaEditMI = helpMenu.add(new MenuItem("About JavaEdit"));
aboutJavaEditMI.addActionListener(this);
// create text editing area
text = new TextArea();
add(text, BorderLayout.CENTER);
}
// implementing ActionListener
public void actionPerformed(ActionEvent event) {
Object source = event.getSource();
if(source == newMI) {
clearText();
fileName = null;
setTitle("JavaEdit"); // reset frame title
}
else if(source == openMI) {
doOpen();
}
else if(source == saveMI) {
doSave();
}
else if(source == saveAsMI){
doSaveAs();
}
else if(source == exitMI) {
System.exit(0);
}
else if(source == cutMI) {
doCopy();
doDelete();
}
else if(source == copyMI) {
doCopy();
}
else if(source == pasteMI) {
doPaste();
}
else if(source == deleteMI) {
doDelete();
}
}
/**
* method to specify and open a file
*/
private void doOpen() {
// display file selection dialog
FileDialog fDialog = new FileDialog(this, "Open ...", FileDialog.LOAD);
fDialog.setVisible(true);
// Get the file name chosen by the user
String name = fDialog.getFile();
// If user canceled file selection, return without doing anything.
if(name == null)
return;
fileName = fDialog.getDirectory() + name;
// Try to create a file reader from the chosen file.
FileReader reader=null;
try {
reader = new FileReader(fileName);
} catch (FileNotFoundException ex) {
MessageDialog dialog = new MessageDialog(this, "Error Message",
"File Not Found: "+fileName);
dialog.setVisible(true);
return;
}
BufferedReader bReader = new BufferedReader(reader);
// Try to read from the file one line at a time.
StringBuffer textBuffer = new StringBuffer();
try {
String textLine = bReader.readLine();
while (textLine != null) {
textBuffer.append(textLine + '\n');
textLine = bReader.readLine();
}
bReader.close();
reader.close();
} catch (IOException ioe) {
MessageDialog dialog = new MessageDialog(this, "Error Message",
"Error reading file: "+ioe.toString());
dialog.setVisible(true);
return;
}
setTitle("JavaEdit: " +name); // reset frame title
text.setText(textBuffer.toString());
}
/**
* method to clear text editing area
*/
private void clearText() {
text.setText("");
}
/**
* method to copy selected text to the clipBoard
*/
private void doCopy() {
clipBoard = new String(text.getSelectedText());
}
/**
* method to delete selected text
*/
private void doDelete() {
text.replaceRange("", text.getSelectionStart(), text.getSelectionEnd());
}
/**
* method to replace current selection with the contents of the clipBoard
*/
private void doPaste() {
if(clipBoard != null) {
text.replaceRange(clipBoard, text.getSelectionStart(),
text.getSelectionEnd());
}
}
/**
* class for message dialog
*/
class MessageDialog extends Dialog implements ActionListener {
private Label message;
private Button okButton;
// Constructor
public MessageDialog(Frame parent, String title, String messageString) {
super(parent, title, true);
setSize(400, 100);
setLocation(150, 150);
setLayout(new BorderLayout());
message = new Label(messageString, Label.CENTER);
add(message, BorderLayout.CENTER);
Panel panel = new Panel(new FlowLayout(FlowLayout.CENTER));
add(panel, BorderLayout.SOUTH);
okButton = new Button(" OK ");
okButton.addActionListener(this);
panel.add(okButton);
}
// implementing ActionListener
public void actionPerformed(ActionEvent event) {
setVisible(false);
dispose();
}
}
/**
* the main method
*/
public static void main(String[] argv) {
// create frame
JavaEdit frame = new JavaEdit();
Dimension size = Toolkit.getDefaultToolkit().getScreenSize();
frame.setSize(size.width-80, size.height-80);
frame.setLocation(20, 20);
// add window closing listener
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
// show the frame
frame.setVisible(true);
}
}