Java hangman game with gui, problems with incrementing/decrementing numbers

问题

The following part of the code doesn't work, as the won/lost count keeps incrementing by more than 1 for each word, and sometimes I get a nullpointerexception with the string length. Moreover, although the player is supposed to get 7 tries(int no), sometimes he gets more, sometimes less. The Strings are taken from a text file "Hangeng.txt". The whole game is inside a keyboard keytyped listener that is inside a button listener. Any tips on how the layout of the game should generally be arranged so as to avoid errors are welcome, as I am only beginning to work with swing and gui stuff.

        public class test{
static int won = 0;
static int lost = 0;
static String key = "";
static String word = null;
static int no = 0;
static StringBuffer toguess;

      public static void main(String[] args) throws IOException{

 JFrame frame = new JFrame();
  frame.setLayout(new GridLayout(3,1));
      JPanel panel1 = new JPanel();
     JPanel panel2 = new JPanel();
      JPanel panel3 = new JPanel();
         JButton button = new JButton();
           JLabel label = new JLabel();
           JLabel label2 = new JLabel();
            panel1.add(label);
              panel2.add(button);
                  panel3.add(label2);
                    frame.setSize(800,600);
                   frame.add(panel1);
                          frame.add(panel2);
                      frame.add(panel3);
                     frame.setVisible(true);

 //the button that starts the game or gets a new word
 button.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            frame.requestFocus();

                no = 0;

                label2.setText("won " + won + ", lost " + lost);
                button.setText("Next");


                                    //get random word from file
                BufferedReader reader = null;
                try {
                    reader = new BufferedReader(new FileReader(
                            "hangeng.txt"));
                } catch (FileNotFoundException e1) {
                    e1.printStackTrace();
                }
                int lineno = (int) (Math.random() * 100);
                for (int i = 0; i < lineno; i++) {
                    try {
                        reader.readLine();
                    } catch (IOException e1) {
                        e1.printStackTrace();
                    }
                }

                try {
                    word = reader.readLine().replace(" ", "");
                } catch (IOException e1) {
                    e1.printStackTrace();
                }




                String missing = "";
                for (int u = 0; u < (word.length() - 2); u++) {
                    missing = missing + "*";
                }
                final String guess = word.charAt(0) + missing
                        + word.charAt((word.length() - 1));
                toguess = new StringBuffer(guess);
                label.setText(toguess.toString());
                final ArrayList<String> tried = new ArrayList<String>();



            //keylistener that listens to key clicks by the user

         frame.addKeyListener(new KeyListener() {
                    public void keyPressed(KeyEvent arg0) {
                    }

                    public void keyReleased(KeyEvent arg0) {
                    }

                    public void keyTyped(KeyEvent arg0) {
                        key = "" + arg0.getKeyChar();
                        String guessing = null;
                        boolean k = false;

                        if ((no < 6)) {
                            guessing = key;
                            System.out.println(guessing);
                            if (!(tried.contains(guessing))) {
                                tried.add(guessing);
                                for (int length = 1; length < (guess
                                        .length() - 1); length++) {
                                    if (guessing.equals(String.valueOf(word.charAt(length)))) {
                                        toguess.replace(length,
                                                (length + 1),
                                                String.valueOf(word.charAt(length)));
                                        k = true;
                                    }
                                }
                                if (k == true) {
                                    label.setText(toguess.toString());
                                } else {
                                    no = no + 1;
                                }
                                k = false;
                            }
                            label.setText(toguess.toString());
                            if (toguess.toString().equals(word)) {
                                label.setText("Correct! The word was "  + word);
                                no = 6;
                                won = won + 1;
                            }
                        }
                        else if ((no == 6)
                                && (!(toguess.toString().equals(word)))) {
                            label.setText("Sorry, but the word was " + word);

                            lost = lost + 1;
                        }
                    }
                });
            }

    }); 

          }
   }

回答1:

+1 to all comments....

Adding to them:

• Do not use KeyListener use a KeyAdapter however as you are using Swing and not AWT you should use KeyBindings for Swing see here for example.

• Dont forget to create and manipulate Swing components on Event Dispatch Thread via SwingUtiltities.invokeLater(..) block see here for more.

• Check class naming schemes they shuld start with capital letter, i.e test should be Test and every new word after that should be capitalized.

• Do not call setSize on JFrame rather use appropriate LayoutManager and/or override getPreferredSize() of JPanel and return a size which fits its content and call pack() on JFrame instance after adding all components.

• Also SSCCE should be compilable from copy and paste this is not.... i.e variables needed to be changed to final and I dont have a sample of Hangeng.txt so cant test

• Lastly use the @Override annotation to ensure you are overriding the correct methods, i.e

  @Override
  public void actionPerformed(ActionEvent e) {
  
  }
  

来源：https://stackoverflow.com/questions/14012023/java-hangman-game-with-gui-problems-with-incrementing-decrementing-numbers