我正在创建数独游戏，并尝试提供保存、另存为和打开游戏的选项。我正在使用 JFileChooser 来执行此操作。我可以保存（或“另存为”），但是当我尝试打开保存的文件时，出现错误。我是编程新手，我希望有人能发现问题并教育我在保存时如何阅读数独板的内容（以及打开时如何处理重新创建数独板文件）。我听说有一种更简单的方法可以使用 InputStream/OutputStream 而不是 Reader/Writer...
这是我实现这个的内部类的代码（我不知道是否有办法在不超过此文本框字符限制的情况下发布我的整个类。）：
// this inner class provides a JMenuBar object at the top of
// the board
class MenuAtTop extends JMenuBar implements ActionListener{
// SudokuMain2 object we are dealing with
private SudokuMain2 main;
// the "File" menu
private JMenu fileMenu;
// the "New Game" option
private JMenuItem newGame;
// the "Open" option
private JMenuItem open;
// the "Save" option
private JMenuItem save;
// the "Save As" option
private JMenuItem saveAs;
// the "Reset" option
private JMenuItem reset;
// the "Quit" option
private JMenuItem quit;
// the ability to choose files
private JFileChooser choose;
// the saved file
// // compiler would not allow "static" keyword
private File fileSaved = null;
private Object opener;
// JDialog object to create a dialog box to prompt
// user for new game information
private JDialog createNewWin;
/**
* Constructs MenuAtTop object.
*
* @param m The SudokuMain2 object to be referred to.
*/
public MenuAtTop(final SudokuMain2 m) {
main = m;
opener = null;
choose = new JFileChooser();
// instantiate and bind to reference
fileMenu = new JMenu("File");
add(fileMenu);
// instantiate and bind to reference
newGame = new JMenuItem("New Game");
newGame.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_N,
ActionEvent.CTRL_MASK));
fileMenu.add(newGame);
newGame.addActionListener(this);
open = new JMenuItem("Open");
open.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_O,
ActionEvent.CTRL_MASK));
fileMenu.add(open);
// add action listener to "Open" option
open.addActionListener(this);
save = new JMenuItem("Save");
save.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S,
ActionEvent.CTRL_MASK));
fileMenu.add(save);
// //save.setEnabled(false);
// add action listener to "Save" option
save.addActionListener(this);
saveAs = new JMenuItem("Save As");
saveAs.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_A,
ActionEvent.CTRL_MASK));
fileMenu.add(saveAs);
// add action listener to "Save As" option
saveAs.addActionListener(this);
reset = new JMenuItem("Reset");
reset.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_R,
ActionEvent.CTRL_MASK));
fileMenu.add(reset);
// add action listener to "Reset" option
reset.addActionListener(this);
quit = new JMenuItem("Quit");
quit.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_Q,
ActionEvent.CTRL_MASK));
fileMenu.add(quit);
// add action listener to "Quit" option
quit.addActionListener(this);
}
public void actionPerformed(ActionEvent e) {
if(e.getSource().equals(quit)) {
closePrompt();
//main.win.dispose();
}
else if(e.getSource().equals(reset)) {
int n = JOptionPane.showConfirmDialog(main.win,
"Any player values will" +
" be lost. Proceed?",
"Warning!", 2);
if(n == JOptionPane.OK_OPTION) {
main.board.reset();
main.view.repaint();
}
}
else if(e.getSource().equals(saveAs)) {
saveAs();
}
else if(e.getSource().equals(save)) {
if(fileSaved == null) {
saveAs();
}
else {
try {
board.writeToStream(new FileOutputStream(fileSaved));
// main.board.setDirty(false);
} catch (Exception ex) {
JOptionPane.showMessageDialog(main.win, "Error saving file.");
}
}
}
else if(e.getSource().equals(open)) {
int returnVal = choose.showOpenDialog(main.win);
if(returnVal == JFileChooser.APPROVE_OPTION) {
boolean error = false;
File openFile = choose.getSelectedFile();
try {
FileInputStream fin = new FileInputStream(openFile);
ObjectInputStream ois = new ObjectInputStream(fin);
opener = ois.readObject();
} catch (Exception ex) {
JOptionPane.showMessageDialog(main.win, "Error opening file.");
error = true;
}
if(opener != null && opener instanceof SudokuBase){
main.west.remove(main.symbols);
main.east.remove(main.view);
//add in state information for new board
main.south.remove(main.rowColRegStates);
main.view = new SudokuView((SudokuBase) opener);
main.symbols = new SetSymbols(main.view);
//add in state information for new board
main.rowColRegStates = new ShowStates(main.view);
main.west.add(main.symbols);
main.east.add(main.view);
//add in state information for new board
main.south.add(main.rowColRegStates);
main.win.requestFocus();
fileSaved = openFile;
// main.board.setDirty(false);
} else {
if(error) {
JOptionPane.showMessageDialog(main.win, " Incorrect file type!");
}
}
}
// else: user cancelled
}
else if(e.getSource().equals(newGame)) {
setEnabled(false);
// create dialog box prompting for the new board information
createNewWin = new Dialog1(main, "Create New Board", true);
// make it visible
createNewWin.setVisible(true);
fileSaved = null;
}
}
// This method prompts the user to choose a file to save to,
// and then saves the file.
private int saveAs() {
boolean saveError;
int rtn = choose.showSaveDialog(main.win);
if(rtn == JFileChooser.APPROVE_OPTION) {
saveError = false;
File fileSaveAs = choose.getSelectedFile();
try {
board.writeToStream(new FileOutputStream(fileSaveAs));
} catch (Exception e) {
JOptionPane.showMessageDialog(main.win, "Error saving file.");
saveError = true;
}
if(!saveError) {
fileSaved = fileSaveAs;
// main.board.setDirty(false);
}
}
return rtn;
}
/**
* Asks the user if they want to save before closing if changes were made.
*/
private void closePrompt() {
if(true) { //board.isDirty()) {
int n = JOptionPane.showConfirmDialog(main.win, "Save game?");
if(n == JOptionPane.YES_OPTION) {
int saved = saveAs();
if(saved != JFileChooser.CANCEL_OPTION){
main.win.dispose();
}
}
else if(n == JOptionPane.NO_OPTION) {
main.win.dispose();
}
}
else
main.win.dispose();
}
}