Question

我正在尝试制作一个简单的计时器，在指定的秒数后发出蜂鸣声。我设法让它工作，但TimerTask继续在蜂鸣声后运行。现在我要停止执行吗？这是我的代码：

import java.util.Scanner;
import java.util.Timer;
import java.util.TimerTask;
import java.awt.Toolkit;

class Alarm {

    public static void main(String[] args) {
        long delay;
        Scanner scan = new Scanner(System.in);
        System.out.print("Enter a delay in seconds: ");
        delay = scan.nextInt()*1000;

        Timer timer = new Timer();

        TimerTask task = new TimerTask() {
            @Override
            public void run() {
                Toolkit.getDefaultToolkit().beep();
            }
        };

        timer.schedule(task, delay);
    }
}

Answer 1

您需要通过调用以下方法来取消计时器

timer.cancel();  // Terminates this timer, discarding any currently scheduled tasks.
timer.purge();   // Removes all cancelled tasks from this timer's task queue.

这将取消任务，所以这样的事情会起作用：

import java.util.Scanner;
import java.util.Timer;
import java.util.TimerTask;
import java.awt.Toolkit;

class Alarm {

    private static boolean run = true;

    public static void main(String[] args) {
        long delay;
        Scanner scan = new Scanner(System.in);
        System.out.print("Enter a delay in seconds: ");
        delay = scan.nextInt()*1000;

        final Timer timer = new Timer();

        final TimerTask task = new TimerTask() {
            @Override
            public void run() {
                if(run) {
                   Toolkit.getDefaultToolkit().beep();
                } else {
                   timer.cancel();
                   timer.purge();
                }
            }
        };

        timer.schedule(task, delay);

        // set run to false here to stop the timer.
        run = false;
    }
}

Answer 2

这对我有用（也使用了purge（）建议）：

import java.util.Scanner;
import java.util.Timer;
import java.util.TimerTask;
import java.awt.Toolkit;

class Alarm {

    public static void main(String[] args) {
        long delay;
        Scanner scan = new Scanner(System.in);
        System.out.print("Enter a delay in seconds: ");
        delay = scan.nextInt()*1000;

        final Timer timer = new Timer();

        final TimerTask task = new TimerTask() {
            @Override
            public void run() {
                Toolkit.getDefaultToolkit().beep();
                timer.cancel();
                timer.purge();
            }
        };

        timer.schedule(task, delay);
    }
}

Answer 3

cancel()应该这样做 - cancel停止取消给定的TimerTask / Timer

Answer 4

isStart = true; // 如果调用了真正的定时器函数 countiue ，否则时间被取消
定时器 timer = new Timer(); timer.schedule(new TimerClass(), 0, 5000);

class TimerClass extends TimerTask {
    
    public void run() {
        
        if (isStart) {
           yourFunction();
        }else {
            cancel();
        }

    }
}

如何停止运行TimerTask

4 个答案: