AsyncTask is a generically typed class, and exposes three type parameters:
abstract class AsyncTask<Params, Progress, Result>
When we declare an AsyncTask subclass, we'll specify types for Params, Progress, and Result; for example, if we want to pass a String parameter to doInBackground, report progress as a Float, and return a Boolean result, we would declare our AsyncTask subclass as follows:
public class MyTask extends AsyncTask<String, Float, Boolean>
If we don't need to pass any parameters, or don't want to report progress, a good type to use for those parameters is java.lang.Void, which signals our intent clearly, because Void is an uninstantiable class representing the void keyword.
Let's take a look at a first example, performing an expensive calculation in the background and reporting the result to the main thread:
public class PrimesTask
extends AsyncTask<Integer, Void, BigInteger> {
private TextView resultView;
public PrimesTask(TextView...