gistfile1.txt

    void checkSiteForVersionChange() throws PackageManager.NameNotFoundException {
        PackageInfo pInfo = getPackageManager().getPackageInfo(getPackageName(), 0);
        final String currentVersion = pInfo.versionName;
        class FtpTask extends AsyncTask<Void, Integer, Void> {
            FTPClient con;
            boolean succeed = false;
            String error = "";
            String errorS = "";
            private Context context;

            String newVersion = "";


            public FtpTask(Context context) { this.context = context; }

            protected void onPreExecute() {
                newVersion = currentVersion;
            }

            protected Void doInBackground(Void... args) {
                try {
                    con = new FTPClient();
                    con.connect(InetAddress.getByName("5.9.0.183"));

                    if (con.login("ftpUsername", "ftpPassword")) {
                        con.enterLocalPassiveMode(); // important!

                        InputStream inputStream;
                        BufferedReader r;

                        inputStream = con.retrieveFileStream(s + "versionPro" + s + "lastVersion");
                        r = new BufferedReader(new InputStreamReader(inputStream));
                        newVersion = r.readLine();
                        inputStream.close();
                        r.close();
                        con.completePendingCommand();
                    }
                    con.logout();
                    con.disconnect();

                } catch (Exception e) {
                    error = e.toString();
                    e.printStackTrace();
                }
                return null;
            }

            protected void onPostExecute(Void result) {
                if (!newVersion.equals(currentVersion)) {
                    showDialogExpire();
                    editorMainPrefs.putString("currentVersion", newVersion );
                    editorMainPrefs.commit();
                }
            }
            protected void onProgressUpdate(Integer... args) {
            }
        }
        new FtpTask(MainActivity.this).execute();

    }
    void showDialogExpire() {
        AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
        builder.setTitle("Version notification");
        builder.setMessage("a new version of app has been published this version would you like to see the details ?");
        builder.setIcon(android.R.drawable.ic_dialog_alert);
        builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
//                Uri uriUrl = Uri.parse("http://mydictionary.khaled.ir/");
                Uri uriUrl = Uri.parse("market://details?id=ir.khaled.mydictionary");
                Intent launchBrowser = new Intent(Intent.ACTION_VIEW, uriUrl);
                startActivity(launchBrowser);
            }
        });

        builder.setNegativeButton("Not now", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
//                editorMainPrefs.putInt("lastPost", lastPostNum);
            }
        });
        dialogExpire = builder.create();
        if (!dialogExpire.isShowing())
            dialogExpire.show();
        dialogExpire.setCanceledOnTouchOutside(false);

    }