AsyncTask is still running after onPostExecute() in debug window

Question

I have a program that creates an android application.

The main class of this program uses Async Tasks to connect, then request data. Both connect and request data are started via a button and a progress bar is displayed in both cases.

When I start the Async Task for connect, the program runs through the methods onPreExecute(), doInBackground(), onProgressUpdate() and onPostExecute(), which is as expected.

However after onPostExecute(), when I look in the debugger window, AsyncTask is still running and continues to run. When I then request data, a new AsyncTask is created and I have two running.

How do I terminate the first AsyncTask (and indeed the second once it has finished) as after using the program for a while I end up with around 20 AsyncTask threads still running!

I've included my code below:

private ProgressDialog connectionDialog;
private ProgressDialog requestDataDialog;

private ProgressDialog usingDialog;

private int currentDialog;

public void connectClick(View view) //When the connect button is clicked
{
    currentDialog = 1;

    new PerformTask().execute();
}

private class PerformTask extends AsyncTask<Void, Integer, Integer> 
{
    protected void onPreExecute()
    {
        showDialog(currentDialog);
    }

    protected Integer doInBackground(Void... voi) 
    {
        int total = 0;

        //Perform the task required

        publishProgress(total);

        return total;
    }

    protected void onProgressUpdate(Integer... progress) 
    {
        usingDialog.setProgress(progress[0]);
    }

    protected void onPostExecute(Integer result) 
    {
        removeDialog(currentDialog);
    }
}

protected Dialog onCreateDialog(int id) 
{   
    //Setup the dialogs
}

public void requestDownloadClick(View view)
{
    currentDialog = 2;

    new PerformTask().execute();
}

Answer 1

Just for completeness and so I can accept the question, here is the answer, given by grv_9098, found at stackoverflow.com/a/3077508/1514187 :

AsyncTask manages a thread pool, created with ThreadPoolExecutor. It will have from 5 to 128 threads. If there are more than 5 threads, those extra threads will stick around for at most 10 seconds before being removed. (note: these figures are for the presently-visible open source code and vary by Android release).

Leave the AsyncTask threads alone, please.