Using riot-api-java within Android app. (AsyncTask)

MainActivity.java

public class MainActivity extends Activity{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final Button button = (Button) findViewById(R.id.button1);
        button.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                FetchSummonerTask summonerTask = new FetchSummonerTask();
                summonerTask.execute("summoner name");
            }
        });

    }

    public class FetchSummonerTask extends AsyncTask<String, Void, Summoner> {

        @Override
        protected Summoner doInBackground(String... params) {

            try {
                Summoner summoner = ((GlobalClass)getActivity().getApplication()).getApi()
                        .getSummonerByName(params[0])
                        .get(params[0].replaceAll("\\s+", "").toLowerCase());
                if(summoner != null) {
                    return summoner;
                }
            } catch (RiotApiException e) {
                e.printStackTrace();
            }

            return null;
        }

        @Override
        protected void onPostExecute(Summoner result) {
            super.onPostExecute(result);
            if(result != null) {
                TextView dis = (TextView) findViewById(R.id.textView1);
                dis.setText(String.valueOf((result.getSummonerLevel())));
            }
        }
    }
}