PlayStore checker

CheckUpdate.java

/*
 * Copyright [2016] [Alejandro Platas Mallo]
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package es.dixitalinteractive.rallyenaron.utils;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager.NameNotFoundException;
import android.net.Uri;
import android.os.AsyncTask;
import android.support.annotation.Nullable;
import android.util.Log;
import android.widget.Toast;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * @author Alejandro Platas Mallo
 * @version 1.01
 * @since 18/5/15
 */
public class CheckUpdate extends AsyncTask<String, Void, String> {

    private Boolean found;
    private Activity activity;
    private String versionName;

    public CheckUpdate(Activity activity) {
        this.activity = activity;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();

        try {
            versionName = activity.getPackageManager()
                    .getPackageInfo(activity.getPackageName(), 0).versionName;
            versionName = versionName.replace(".", "");
            versionName = versionName.trim();
            Log.i("Version name: ", versionName);
        } catch (NameNotFoundException e) {
            e.printStackTrace();
        }
    }

    @Override
    protected String doInBackground(String... params) {
        String result;

        try {

            String response = readStream(params[0]);
            result = processResponse(response);
            return result;

        } catch (Exception e) {

            return null;

        }
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);

        if (result == null) {
            Toast.makeText(activity, "Error buscando actualizaciones", Toast.LENGTH_SHORT).show();
        }

        if (result != null) {
            Log.i("ONLINE VERSION", result);
            Log.i("DEVICE VERSION", versionName);
            if (Integer.valueOf(result) > Integer.valueOf(versionName) && found) {
                if (!activity.isFinishing()) {
                    createAlertDialog();
                }
            }
        }
    }

    private void createAlertDialog() {
        AlertDialog.Builder bld = new AlertDialog.Builder(activity);
        bld.setTitle("Actualizar");
        bld.setMessage("Se ha encontrado una nueva versión de la aplicación en Google Play. ¿Desea actualizar?");
        bld.setPositiveButton("Actualizar", new DialogInterface.OnClickListener() {

            @Override
            public void onClick(DialogInterface dialog, int id) {
                activity.startActivity(new Intent(Intent.ACTION_VIEW, Uri
                        .parse("market://details?id=es.dixitalinteractive.rallyenaron")));
            }
        });

        bld.setNegativeButton("No", null);

        bld.create().show();
    }

    private String readStream(String s) {
        StringBuilder result = new StringBuilder();

        HttpURLConnection urlConnection = null;

        try {

            URL url = new URL(s);
            urlConnection = (HttpURLConnection) url.openConnection();
            InputStream in = new BufferedInputStream(urlConnection.getInputStream());

            BufferedReader reader = new BufferedReader(new InputStreamReader(in));

            String line;
            while ((line = reader.readLine()) != null) {
                result.append(line);
            }

        } catch (Exception e) {
            e.printStackTrace();
        } finally {

            if (urlConnection != null) {
                urlConnection.disconnect();
            }
        }

        return result.toString();
    }

    @Nullable
    private String processResponse(String response) {
        String result;// <div class="content" itemprop="softwareVersion"> 2.0  </div>
        String searchString = "itemprop=\"softwareVersion\">";

        // Return true if exists the search string
        found = response.contains(searchString);

        if (!found) {

            return null;

        } else {

            // temp Store a string
            // itemprop="softwareversion.......
            String temp = response.substring(response.indexOf(searchString));

            result = response.substring(response.indexOf(searchString), response.indexOf(searchString)
                    + temp.indexOf("<"));
            result = result.substring(result.indexOf(">") + 2);
            result = result.replace(".", "");
            result = result.trim();

        }

        return result;
    }
}