JAVAFX, обратный отсчет не работает

Question

Счетчик не работает. Я запускаю его через кнопку.

public void startCountDown() { 
    timer.schedule(new TimerTask() { 
    @Override 
     public void run() { 
     Platform.runLater(new Runnable() { 
      public void run() { 
       countDown--; 
       countDownText.setText("Time left:" + countDown); 

       if (countDown < 0) 
        timer.cancel(); 
      } 
     }); 
    } 
    }, 1000); //Every 1 second 
} 

Переменная CountDown устанавливается на 60, так что обратный отсчет времени начинается при 60

EDIT: Обратный отсчет застревает на 59 секунд, таймер обратного отсчета является Int. Нет ошибок. И countDownText объявляется как текст.

@FXML 
private Text countDownText; 

Answer 1

Там больше, чем 1 класс таймера, но я предполагаю, что вы использовали java.util.Timer

Рассматривая API показывает, вы использовали этот метод:

public void schedule(TimerTask task, 
      long delay) 

Schedules the specified task for execution after the specified delay. 

Parameters: 
    task - task to be scheduled. 
    delay - delay in milliseconds before task is to be executed. 
Throws: 
    IllegalArgumentException - if delay is negative, or delay + System.currentTimeMillis() is negative. 
    IllegalStateException - if task was already scheduled or cancelled, timer was cancelled, or timer thread terminated. 
    NullPointerException - if task is null 

Так ваша программа ждет 1 секунду затем выполняет метод run(), но не повторяет. Для того, чтобы сделать его повторить, вам нужно использовать этот метод:

public void schedule(TimerTask task, 
      long delay, 
      long period) 

Schedules the specified task for repeated fixed-delay execution, beginning after the specified delay. Subsequent executions take place at approximately regular intervals separated by the specified period. 

In fixed-delay execution, each execution is scheduled relative to the actual execution time of the previous execution. If an execution is delayed for any reason (such as garbage collection or other background activity), subsequent executions will be delayed as well. In the long run, the frequency of execution will generally be slightly lower than the reciprocal of the specified period (assuming the system clock underlying Object.wait(long) is accurate). 

Fixed-delay execution is appropriate for recurring activities that require "smoothness." In other words, it is appropriate for activities where it is more important to keep the frequency accurate in the short run than in the long run. This includes most animation tasks, such as blinking a cursor at regular intervals. It also includes tasks wherein regular activity is performed in response to human input, such as automatically repeating a character as long as a key is held down. 

Parameters: 
    task - task to be scheduled. 
    delay - delay in milliseconds before task is to be executed. 
    period - time in milliseconds between successive task executions. 
Throws: 
    IllegalArgumentException - if delay < 0, or delay + System.currentTimeMillis() < 0, or period <= 0 
    IllegalStateException - if task was already scheduled or cancelled, timer was cancelled, or timer thread terminated. 
    NullPointerException - if task is null 

Вы можете просмотреть полную документацию здесь: http://docs.oracle.com/javase/7/docs/api/java/util/Timer.html#schedule%28java.util.TimerTask,%20long%29

Вот что я думаю, что это правильный код:

public void startCountDown() { 
    timer.schedule(new TimerTask() { 
    @Override 
     public void run() { 
     Platform.runLater(new Runnable() { 
      public void run() { 
       countDown--; 
       countDownText.setText("Time left:" + countDown); 

       if (countDown < 0) 
        timer.cancel(); 
      } 
     }); 
    } 
    }, 1000, 1000); //Every 1 second 
}