how do i implement android mapbox android sdk successfully in fragment - mapbox

Question

I am using mapbox in a fragment with bottom navigation, when i exit and resume the app or when i change tabs rapidly, the app crashes. this is the error i get
10-07 22:20:36.046 21867-21886/com.dropexpress.driver.dropexpressdriver E/Mbgl-FileSource: Failed to read the storage key:
java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.os.Bundle.getBoolean(java.lang.String, boolean)' on a null object reference
at com.mapbox.mapboxsdk.storage.FileSource.getCachePath(FileSource.java:88)
at com.mapbox.mapboxsdk.storage.FileSource$FileDirsPathsTask.doInBackground(FileSource.java:165)
at com.mapbox.mapboxsdk.storage.FileSource$FileDirsPathsTask.doInBackground(FileSource.java:155)
at android.os.AsyncTask$2.call(AsyncTask.java:304)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
at java.lang.Thread.run(Thread.java:761)
the below code always fails when i exit the app and resume, or when i change tabs rapidly, i am using bottom navigation.
Steps to reproduce
here is my fragment code
package com.dropexpress.driver.dropexpressdriver.fragments;
import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.dropexpress.driver.dropexpressdriver.R;
import com.mapbox.mapboxsdk.Mapbox;
import com.mapbox.mapboxsdk.maps.MapView;
public class HomeFragment extends Fragment {
private MapView mapView;
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
public HomeFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* #param param1 Parameter 1.
* #param param2 Parameter 2.
* #return A new instance of fragment HomeFragment.
*/
// TODO: Rename and change types and number of parameters
public static HomeFragment newInstance(String param1, String param2) {
HomeFragment fragment = new HomeFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_home, container, false);
Mapbox.getInstance(requireActivity(), "pk.eyJ1Ijoic3ludGF4bHRkIiwiYSI6ImNqaDJxNnhzbDAwNnMyeHF3dGlqODZsYjcifQ.pcz6BWpzCHeZ6hQg4AH9ww");
mapView = (MapView) view.findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
return view;
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
#Override
public void onResume() {
super.onResume();
mapView.onResume();
}
#Override
public void onPause() {
super.onPause();
mapView.onPause();
}
#Override
public void onStop() {
super.onStop();
mapView.onStop();
}
#Override
public void onLowMemory() {
super.onLowMemory();
mapView.onLowMemory();
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
mapView.onSaveInstanceState(outState);
}
}
Android versions: 5.0 +
Device models: motorola g5
Mapbox SDK versions: 6.5.0

Answer 1

Put your Mapbox.getInstance before inflating your layout.
Mapbox.getInstance(requireActivity(),"Your Map Key");
View view = inflater.inflate(R.layout.fragment_home, container, false);
mapView = (MapView) view.findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
I hope this helps you.

Answer 2

i opened this issue in github, you check their response here
https://github.com/mapbox/mapbox-gl-native/issues/13044#issuecomment-427861016
this was their response:
I can see 2 issues with the provided code:
You are not calling MapView#onDestroy, this has to be called from you fragment's #onDestroyView.
MapView#onCreate should be called from fragment's #onViewCreatedinstead of #onCreateView.
I applied the changes and it worked!