AsyncTask that provide an listener to handle callbacks

FetchMovieListTask.java

import android.net.Uri;
import android.os.AsyncTask;
import android.util.Log;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by eltonjhony on 17/03/18.
 */

public class FetchMovieListTask extends AsyncTask<String, Void, List<Info>> {

    private final String LOG_TAG = FetchMovieListTask.class.getSimpleName();

    private static final String API_KEY = "Put your KEY here";
    private static final String BASE_IMG_PATH = "http://image.tmdb.org/t/p/w500";
    private final String BASE_URL = "http://api.themoviedb.org/3/discover/movie?api_key=" + API_KEY;

    private OnLoadMoviesListener listener;

    public FetchMovieListTask(OnLoadMoviesListener listener) {
        this.listener = listener;
    }

    @Override
    protected List<Info> doInBackground(String... params) {
        Log.d(LOG_TAG, "Execute task");
        if (params == null || params.length == 0) {
            return null;
        }
        HttpURLConnection urlConnection = null;
        BufferedReader reader = null;
        List<Info> movieList;
        try {
            Uri.Builder builder = Uri.parse(BASE_URL).buildUpon();
            builder.appendQueryParameter("sort_by", params[0]);
            URL url = new URL(builder.toString());
            Log.d(LOG_TAG, "URL: " + url);
            // Create the request to OpenWeatherMap, and open the connection
            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setRequestMethod("GET");
            urlConnection.connect();

            // Read the input stream into a String
            InputStream inputStream = null;
            try {
                inputStream = urlConnection.getInputStream();
            } catch (IOException e) {
                Log.e(LOG_TAG, e.getMessage());
            }
            StringBuffer buffer = new StringBuffer();
            if (inputStream == null) {
                // Nothing to do.
                return null;
            }
            reader = new BufferedReader(new InputStreamReader(inputStream));

            String line;
            while ((line = reader.readLine()) != null) {
                // Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
                // But it does make debugging a *lot* easier if you print out the completed
                // buffer for debugging.
                buffer.append(line + "\n");
            }

            if (buffer.length() == 0) {
                // Stream was empty.  No point in parsing.
                return null;
            }
            movieList = getMovieInfo(buffer.toString());
        } catch (IOException e) {
            Log.e(LOG_TAG, "Error ", e);
            return null;
        } catch (JSONException e) {
            Log.e(LOG_TAG, "Error ", e);
            // If the code didn't successfully get the weather data, there's no point in attemping
            // to parse it.
            return null;
        } finally {
            if (urlConnection != null) {
                urlConnection.disconnect();
            }
            if (reader != null) {
                try {
                    reader.close();
                } catch (final IOException e) {
                    Log.e(LOG_TAG, "Error closing stream", e);
                }
            }
        }
        Log.d(LOG_TAG, "Execute task finish");
        return movieList;
    }

    @Override
    protected void onPostExecute(List<Info> infos) {
        super.onPostExecute(infos);
        listener.onSuccess(infos);
    }

    private List<Info> getMovieInfo(String jsonStr) throws JSONException {
        JSONObject jsonObject = new JSONObject(jsonStr);
        JSONArray movieListJson = jsonObject.getJSONArray("results");
        List<Info> pathList = new ArrayList<Info>();
        for (int i = 0; i < movieListJson.length(); i++) {
            JSONObject movieJson = movieListJson.getJSONObject(i);

            Long id = movieJson.getLong("id");
            String posterPath = BASE_IMG_PATH + movieJson.getString("poster_path");
            String overview = movieJson.getString("overview");
            String release_date = movieJson.getString("release_date");
            String original_title = movieJson.getString("original_title");
            Double vote_average = movieJson.getDouble("vote_average");
            Info movieInfo = new Info(id, posterPath, overview, release_date, original_title, vote_average);
            pathList.add(movieInfo);
        }
        return pathList;
    }


    interface OnLoadMoviesListener {
        void onSuccess(List<Info> result);
    }
}