Android: MapView not showing up empty

Issue

I want to show google maps in tabbed layout
So I created a viewPager in main activity and added below fragment for map
But it is showing up empty.

Every overridden function is getting called as expected.
I am not able to understand what exactly is causing map to not show up.

Below is my code

fragment_map.xml

<?xml version="1.0" encoding="utf-8"?>
<com.google.android.gms.maps.MapView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:map="http://schemas.android.com/apk/res-auto"
    android:name="com.google.android.gms.maps.SupportMapFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:apiKey="@string/google_maps_key"

    android:id="@+id/mapView" >

</com.google.android.gms.maps.MapView>

MapFragment.java

    import android.os.Bundle;
    import android.support.v4.app.Fragment;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;

    import com.google.android.gms.maps.CameraUpdateFactory;
    import com.google.android.gms.maps.GoogleMap;
    import com.google.android.gms.maps.MapView;
    import com.google.android.gms.maps.OnMapReadyCallback;
    import com.google.android.gms.maps.model.LatLng;
    import com.google.android.gms.maps.model.MarkerOptions;
    import com.i2e1.iconnect.R;

    import java.util.ArrayList;
    import java.util.List;

    public class MapFragment extends Fragment implements OnMapReadyCallback {

        MapView m;
        GoogleMap googleMap;
        private List<MarkerOptions> markers;

        public MapFragment() {
            // Required empty public constructor
        }

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            View v = inflater.inflate(R.layout.fragment_map, container, false);
            m = (MapView) v.findViewById(R.id.mapView);
            m.getMapAsync(this);
            m.onCreate(savedInstanceState);
            return v;
        }

        @Override
        public void onResume() {
            super.onResume();
            m.onResume();
        }

        @Override
        public void onPause() {
            super.onPause();
            m.onPause();
        }

        @Override
        public void onDestroy() {
            super.onDestroy();
            m.onDestroy();
        }

        @Override
        public void onLowMemory() {
            super.onLowMemory();
            m.onLowMemory();
        }

        @Override
        public void onMapReady(GoogleMap googleMap) {
            this.googleMap = googleMap;
            for (MarkerOptions m : markers) {
                googleMap.addMarker(new MarkerOptions()
                        .position(m.getPosition())
                        .title(m.getTitle()));
            }
            googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(markers.get(0).getPosition(), 15), 5000, null);
            m.onResume();
        }
}

Solution

Sorry Guys

It was a simple problem. I just factory reset a device to test and it was never connected to WIFI/mobile data before launching app.

Problem got resolved just after connecting to wifi.

Answered By - Ravi Sahu