计时器任务在 java 中出现错误

Question

我正在 java 中制作一个简单的游戏，我想在其中计算用户猜测数字所需的时间，但它告诉我：从内部引用的局部变量 class 必须是最终的或有效的 final.Thanks 提前...

这是游戏的代码

    //Creating the random number with the user initialized random class
    Random rand = new Random();
    int  n = rand.nextInt(20) + 1;

    //Variables are declared
    int lives = 10; 
    int secondsPassed = 0;

    //The JOptionPane (Pop-up window) is intitialized
    JOptionPane j = new JOptionPane(JOptionPane.INFORMATION_MESSAGE); 

    Timer timer = new Timer();
    TimerTask task = new TimerTask(){
        public void run(){
            secondsPassed++;
        }
    };

    while (true){

    int num = Integer.parseInt(JOptionPane.showInputDialog(j,"I am thinking of a number between 1 and 20. You have " + lives + " lives. Can you guess it?","EasyMode Singleplayer",JOptionPane.INFORMATION_MESSAGE));
    timer.scheduleAtFixedRate(task,1000,1000);

    //Here the program decides if the user has lost the game or if he still has lives left        
    if(lives == 0){

        JOptionPane.showMessageDialog(j,"You have lost the game!","EasyMode singleplayer",JOptionPane.INFORMATION_MESSAGE);
        System.exit(0);

    }else if(lives > 0){                
        //The program checks to see if the number is Higher/Lower or equal to the random number generated        
        if(num == n){

            String options[] = {"Yes","No"};
            timer.cancel();
            timer.purge();

            JOptionPane.showMessageDialog(j,"You are correct ! You finished the game with " + lives + " lives!" );
            int saving = JOptionPane.showOptionDialog(j,"Do you want to save your score?","Save",JOptionPane.YES_NO_CANCEL_OPTION,JOptionPane.QUESTION_MESSAGE, null, options,options[1]);
            //Here the program asks the player if he wants to save his lives to his home directory
            if(saving == 0){                            
              try{
                String userHomeFolder = System.getProperty("user.home");
                File file = new File(userHomeFolder,"Scores.txt");
                file.createNewFile();
                FileWriter writer = new FileWriter(file);

                writer.write("You finished EASYMODE with " + lives + " lives out of 10 lives on Guess The Number!");
                writer.write("It only took you " + secondsPassed);
                writer.flush();
                writer.close();
                //bar.add(panel);

                JOptionPane.showMessageDialog(j,"File successfully saved to your home directory!","File Saved",JOptionPane.INFORMATION_MESSAGE);
                System.exit(0);

              }catch(IOException e){
                 e.printStackTrace();
              }
             }else{
                System.exit(0);
             }

Answer 1

我不知道将 Timer 与 TimerTask 一起使用是否重要，但如果不重要，您可以只测量开始和结束时的时间：

long start = System.currentTimeMillis();
...

long end = System.currentTimeMillis();
...

long secondsPassed = (end - start) / 1000;

计时器任务在 java 中出现错误

Timer Task giving errors in java

java

timer

timertask