Question

我想做一个计时器，当事情发生时它会重新启动：

public static Timer timer;

public myTimer(long MAC, String ipAddress){
    timer = new Timer();
    timer.schedule(timerTask, 120000); 
}

public void update(){
    timer.cancel();
    timer = new Timer();
    timer.schedule(timerTask, 120000); 
}

创建新计划时遇到问题，我有这个错误：

java.lang.IllegalStateException: Task already scheduled or cancelled
    at java.util.Timer.sched(Timer.java:358)
    at java.util.Timer.schedule(Timer.java:170)
    at spb.keepAliveTimer.update(keepAliveTimer.java:37)
    at spb.keepAlive.update(keepAlive.java:58)
    at spb.receptor.keepAlive(receptor.java:475)
    at spb.receptor.run(receptor.java:118)
    at java.lang.Thread.run(Thread.java:662)

我不知道怎么办呢！谢谢！

Answer 1

这对我来说很好......你能粘贴完整的代码和错误吗？

package snippet;

import java.util.Timer;
import java.util.TimerTask;

public class Main {
    public static Timer timer;

    public static void main(String[] args) {
        Main main = new Main();
        main.myTimer(123, "127.0.0.1");


    }

    public void myTimer(final long MAC, final String ipAddress) {
        TimerTask timerTask = new TimerTask() {

            @Override
            public void run() {
                System.out.println("MAC: " + MAC + "ipAddress:" + ipAddress);
                update();
            }
        };
        timer = new Timer();
        timer.schedule(timerTask, 1000);

    }

    public void update() {
        TimerTask timerTask = new TimerTask() {

            @Override
            public void run() {
                System.out.println("Updated timer");

            }
        };
        timer.cancel();
        timer = new Timer();
        timer.schedule(timerTask, 2000);
    }
}

输出：

 MAC: 123ipAddress:127.0.0.1
 Updated timer

Answer 2

每次重新启动Timer时都必须创建一个新的TimerTask对象。所以，在Start上创建一个新的。并使用“Timer.cancel”和“Timer.purge”销毁定时器。

例如，我有两个按钮 - 开始和停止

mStartButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
mTimerTask = new TimerTask();//This creates new TimerTask 
timer = new Timer(); //Instantiate again, as we Cancel the Timer
timer.schedule(mTimerTask, 0, 30);
}
});

mEndButton.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
timer.cancel();
timer.purge();
}
});

在java中重启计时器

2 个答案: