public class Download extends AsyncTask<Void, Void, String> {


        protected String doInBackground(Void... params) {

            URL url = null;
            try {
                url = new URL( "http://dagobah.grifin.pt/tiagocoelho/Conexaotumg.php");
            } catch (MalformedURLException e) {
                e.printStackTrace();
            }
            HttpURLConnection conn = null;
            try {
                conn = (HttpURLConnection) url.openConnection();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                if( conn.getResponseCode() == HttpURLConnection.HTTP_OK ){
                    InputStream is = conn.getInputStream();

                }else{
                    InputStream err = conn.getErrorStream();

                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            String out = null;

            try {
                DefaultHttpClient httpClient = new DefaultHttpClient();

                String url_all_empresas = "http://dagobah.grifin.pt/tiagocoelho/Conexaotumg.php";

                final HttpParams httpParameters = httpClient.getParams();

                HttpConnectionParams.setConnectionTimeout(httpParameters, 15000);
                HttpConnectionParams.setSoTimeout(httpParameters, 15000);

                HttpGet httpPost = new HttpGet(url_all_empresas);

                HttpResponse httpResponse = httpClient.execute(httpPost);
                HttpEntity httpEntity = httpResponse.getEntity();

                out = EntityUtils.toString(httpEntity, HTTP.UTF_8);

            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            } catch (ClientProtocolException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }

            return out;
        }

class btnsearchclicker implements Button.OnClickListener
    {
        @Override
        public void onClick(View v){
            AlertDialog.Builder b = new AlertDialog.Builder(MainActivity.this);
            b.setTitle(overflow2);

            b.setItems((overflow.toArray(new String[linhas.size()])), new DialogInterface.OnClickListener() {

                @Override
                public void onClick(DialogInterface dialog, int which) {

                    dialog.dismiss();
                    int j = 0;

                    for (j = 0; j <= overflow.size(); j++) {
                        if (j == which) {

                            btnstackoverflow.setText(overflow.get(j));


                        }
                    }

                }
            });
            b.show();
        }
    }