Run an Async Task (Android)

run_async_task.java

//Declare variable and execute async
  DownloadFilesTask mDonwloadFilesTask;
  mDonwloadFilesTask = new DownloadFilesTask();
  mDonwloadFilesTask.execute("");
//----------------------------------
 public class DownloadFilesTask extends AsyncTask<String, Void, String> {
        protected String doInBackground(String... params) {
          //do all the heavy staff here but dont you dare messing with the UI!
            return "Executed!";
        }

        @Override
        protected void onPostExecute(String result) {
          //here you can even change the layout
        }

        @Override
        protected void onPreExecute() {}

        @Override
        protected void onProgressUpdate(Void... values) {}