SupportMapFragmentManagers getMapAsync() does not trigger onMapReady(GoogleMap map) - google-maps-android-api-2

Question

I have a
public abstract class MyMapFragment implements OnMapReadyCallback
{
//
public GoogleMap googleMap;
SupportMapFragment mapFragment;
#IdRes
public abstract int getSupportMapFragId();
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// http://stackoverflow.com/a/36592000/5102206
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP){
// Do something for lollipop and above versions
mapFragment = (SupportMapFragment) getChildFragmentManager().findFragmentById(getSupportMapFragId());
} else {
// do something for phones running an SDK before lollipop
mapFragment = (SupportMapFragment) getFragmentManager().findFragmentById(getSupportMapFragId());
}
mapFragment.getMapAsync(this);
}
//..
#Override
public void onMapReady(GoogleMap map) {
this.googleMap = map;
}
}
According to my breakpoints onViewCreated() is called, but onMapReady() is not called (breakpoint on this.googleMap = map not triggered)
On Android 5, 6 and 7 it works fine so far and I can see the Map..
On Android 4.X (API 16 - API 19) devices my app starts up, but then it seem to freeze there... I see a white blank screen.
On Android 4.X OS devices:
1. With getFragmentManager(), the mapFragment object is null after the else condition.
2. With getChildFragmentMenager() the mapfragment seem to be valid and non-null, but onMapReady not triggered.
What am I missing here?

Answer 1

Note: You cannot inflate a layout into a fragment when that layout includes a . Nested fragments are only supported when added to a fragment dynamically
If you want to inflate a map in a fragment you can either do it in xml or do it in java code like this:
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
FragmentManager fm = getChildFragmentManager();
SupportMapFragment mapFragment = (SupportMapFragment) fm.findFragmentByTag("mapFragment");
if (mapFragment == null) {
mapFragment = new SupportMapFragment();
FragmentTransaction ft = fm.beginTransaction();
ft.add(R.id.mapFragmentContainer, mapFragment, "mapFragment");
ft.commit();
fm.executePendingTransactions();
}
mapFragment.getMapAsync(callback);
}
And also the simple container
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/mapFragmentContainer"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
</LinearLayout>
Also, you don't need to implement the onMapReadyCallback in the class definition. Instead of callback you create a new OnMapReadyCallback() right there:
MapView.getMapAsync(new OnMapReadyCallback() {
#Override
public void onMapReady(GoogleMap mMap) {
googleMap = mMap;
}
});
You also need these
MapView mMapView;
private GoogleMap googleMap;
I hope this helps somehow !

Answer 2

There was an issue with a blocking thread from RxJava on main thread. So it was not an Google Maps issue.

Answer 3

I don't quite understand why you are nesting fragments, specially because it can cause performance issues.
If you take a look at Google Samples, the Google Maps examples uses an Activity and SupportMapFragment:
public class MapsActivityCurrentPlace extends AppCompatActivity
implements OnMapReadyCallback, ConnectionCallbacks,
OnConnectionFailedListener {
#Override
public void onMapReady(GoogleMap map) {
mMap = map;
// Use a custom info window adapter to handle multiple lines of text in the
// info window contents.
mMap.setInfoWindowAdapter(new GoogleMap.InfoWindowAdapter() {
#Override
// Return null here, so that getInfoContents() is called next.
public View getInfoWindow(Marker arg0) {
return null;
}
#Override
public View getInfoContents(Marker marker) {
// Inflate the layouts for the info window, title and snippet.
View infoWindow = getLayoutInflater().inflate(R.layout.custom_info_contents,
(FrameLayout)findViewById(R.id.map), false);
TextView title = ((TextView) infoWindow.findViewById(R.id.title));
title.setText(marker.getTitle());
TextView snippet = ((TextView) infoWindow.findViewById(R.id.snippet));
snippet.setText(marker.getSnippet());
return infoWindow;
}
});
// Turn on the My Location layer and the related control on the map.
updateLocationUI();
// Get the current location of the device and set the position of the map.
getDeviceLocation();
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState != null) {
mLastKnownLocation = savedInstanceState.getParcelable(KEY_LOCATION);
mCameraPosition = savedInstanceState.getParcelable(KEY_CAMERA_POSITION);
}
setContentView(R.layout.activity_maps);
mGoogleApiClient = new GoogleApiClient.Builder(this)
.enableAutoManage(this /* FragmentActivity */,
this /* OnConnectionFailedListener */)
.addConnectionCallbacks(this)
.addApi(LocationServices.API)
.addApi(Places.GEO_DATA_API)
.addApi(Places.PLACE_DETECTION_API)
.build();
mGoogleApiClient.connect();
}
#Override
public void onConnected(Bundle connectionHint) {
SupportMapFragment mapFragment =
(SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
#Override
public void onConnectionFailed(#NonNull ConnectionResult result) {
Log.d(TAG, result.getErrorMessage());
}
#Override
public void onConnectionSuspended(int cause) {
Log.d(TAG, "Play services connection suspended");
}
}