Question

I have a main form with a button, that when pressed, should start a new count-down timer thread.

This is the code in the button’s action listener:

 Counter c = new Counter(timeToFinish);

This is the code for the Counter class:

class Counter implements Runnable {

        int waitingTime = 0;
        Thread myCounter = new Thread(this);

        public Counter(int waitingTime)
        {
            this.waitingTime = waitingTime;
            myCounter.run();
        }

        public void run(){

            //Start countdown:
            do  
            {

                waitingTime -= 1;

                try {

                    Thread.sleep(1000);
                    System.out.println(waitingTime);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            } while (waitingTime >= 0);

        }
    }

The problem is, when I create a new instance of the Counter class, it pauses the whole program, not just that thread! The problem must be with “Thread.sleep”.

Answer 1

Because you are directly calling the run method.

Instead you should wrap it in a Thread and start the thread.

For e.g., replace

myCounter.run();

by

new Thread(this).start();