Reusing timer in android

Question

In my android app, I have the following relevant piece of code:

/*Code outside*/    
button.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        Timer t = new Timer();
        t.scheduleAtFixedRate(
            new TimerTask(){
                public void run(){
                    stuffToBeDone();
                }
            },someVariableDelay,someVariablePeriod);
    }
}

Everything was going fine until I noticed that stuffToBeDone() was running once for every time I pressed the button. As far as I understand, every time onClick() is called and the old Timer should not exist anymore, but somehow the TimerTask survives.

In the second button click, I no longer have a reference to the first Timer to cancel() it (because it should not exist anymore). And if I declare the Timer as a final variable in the Code outside so that I can do it, after canceling I cannot reuse it anymore. So how can I terminate that TimerTask but then still be able to use a Timer?

Answer 1

Android Timer is thread based from the Android Developers website:

http://developer.android.com/reference/java/util/Timer.html

When a timer is no longer needed, users should call cancel(), which releases the timer's thread and other resources. Timers not explicitly cancelled may hold resources indefinitely.

I would recommend instantiating the timer inside the onclicklistener only i.e. something similar to this:

    /*Code outside*/    
Timer t = null;
button.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        if(t == null)
           t = new Timer();
        else
           t.cancel();
        t.scheduleAtFixedRate(
            new TimerTask(){
                public void run(){
                    stuffToBeDone();
                }
            },someVariableDelay,someVariablePeriod);
    }
}