1

カウントダウンは機能しません。ボタンでトリガーしています。

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
}

countDown 変数は 60 に設定されているため、カウントダウンは 60 から始まります。

編集: カウントダウンは 59 秒で停止します。countDown は int です。エラーなし。また、countDownText はテキストとして宣言されています。

@FXML
private Text countDownText;
4

1 に答える 1

4

複数のタイマー クラスがありますが、java.util.Timer を使用したと仮定します。

API を調べると、このメソッドを使用したことがわかります。

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

したがって、プログラムは 1 秒待ってから run() メソッドを実行しますが、繰り返しません。繰り返すには、次のメソッドを使用する必要があります。

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

ここで完全なドキュメントを表示できます: http://docs.oracle.com/javase/7/docs/api/java/util/Timer.html#schedule%28java.util.TimerTask,%20long%29

これが私が正しいコードだと思うものです：

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
}
于 2014-10-28T19:00:38.370 に答える