android - 谷歌安卓地图应用程序在从数据库中获取纬度和经度时崩溃

Question

我需要在地图上显示巴士位置，我的数据库中保存了纬度和经度。要检索纬度和经度，我正在使用 AsynTask。但我认为我的代码存在一些问题，如果在 onMapReady 中调用 AsyncTask，应用程序会崩溃。我检查了没有调用 AsyncTask 提供手动纬度和经度，它工作正常。请帮我解决问题。

这是我的代码：

 @Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    GetLocation getLocation = new GetLocation(getApplicationContext());
    getLocation.execute();

}

public class GetLocation extends AsyncTask<String,Void,String> {
    Context context;
    GetLocation(Context ctx){
        context = ctx;
    }

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

        return null;
    }

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

    @Override
    protected void onPostExecute(String s) {

        String login_url = "https://www.mywebsite.com/android/getlonglatt.php";

        try {
            URL url = new URL(login_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            String line = "";
            String result="";
            while ((line = bufferedReader.readLine())!=null){
                result += line;
            }
            JSONObject jsonObject = new JSONObject(result);
            String latitudedb = (String) jsonObject.get("latitude");
            String longitudedb = (String) jsonObject.get("longitude");
            String busnum = (String) jsonObject.get("busnum");

            Double newlatt = Double.valueOf(latitudedb);
            Double newlong = Double.valueOf(longitudedb);

            LatLng location = new LatLng(newlatt, newlong);

            MarkerOptions options = new MarkerOptions().position(location).title(busnum);
            mMap.addMarker(options);
            mMap.moveCamera(CameraUpdateFactory.newLatLng(location));
            mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(location,19.2f));

            bufferedReader.close();
            httpURLConnection.disconnect();
        }  catch (JSONException e) {
            e.printStackTrace();
        }  catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    protected void onProgressUpdate(Void... values) {

    }

}