Android Google Maps V2: added marker doesn't appear when map is included as dynamic fragment

Question

I need to add a map dynamically into the app to my MainActivity, otherwise I somehow suffer on memory leaks. Adding the map basically works, but I can't add markers. They just don't appear. That's how I add the map:

activity_main.xml which is used by the MainActivity

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <!-- Placeholder for all fragments -->
    <RelativeLayout
        android:id="@+id/fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

    </RelativeLayout>

    <!-- Slider menu -->
    <LinearLayout
        android:id="@+id/list_container"
        android:layout_width="240dp"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:background="#fff"
        android:orientation="vertical" >

    <!-- more code -->
    </LinearLayout>

</android.support.v4.widget.DrawerLayout>

fragment_map.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@id/fragment_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center" >

        <fragment
            xmlns:map="http://schemas.android.com/apk/res-auto"
            android:id="@+id/fragment_googlemap"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            class="com.androidmapsextensions.SupportMapFragment"
            map:cameraTargetLat="48.21167860510698"
            map:cameraTargetLng="16.365892895859423"
            map:cameraZoom="11"
            map:uiCompass="true"
            map:uiRotateGestures="true"
            map:uiScrollGestures="true"
            map:uiTiltGestures="true"
            map:uiZoomControls="true"
            map:uiZoomGestures="true" />
</FrameLayout>

MapFragment.java

public class MapFragment extends com.androidmapsextensions.SupportMapFragment
{
    private static final String TAG = MapFragment.class.getSimpleName();
    private OnFragmentLoadedCompleteListener onFragmentLoadedCompleteListener;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle args)
    {
        super.onCreateView(inflater, container, args);

        Logger.log(TAG, "onCreateView()", LogController.isLoggingEnabled(), Log.DEBUG);

        return inflater.inflate(R.layout.fragment_map, container, false);
    }

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

        Logger.log(TAG, "onActivityCreated()", LogController.isLoggingEnabled(), Log.DEBUG);

        onFragmentLoadedCompleteListener.onFragmentComplete();
    }

    @Override
    public void onAttach(Activity activity)
    {
        super.onAttach(activity);

        Logger.log(TAG, "onAttach()", LogController.isLoggingEnabled(), Log.DEBUG);

        onFragmentLoadedCompleteListener = (OnFragmentLoadedCompleteListener)activity;
    }
}

Important parts of MainActivity.java

@Override
public void onFragmentComplete()
{
    googleMap = ((SupportMapFragment)getSupportFragmentManager().findFragmentByTag("mapFragment")).getExtendedMap();
}


private void initMapFragment()
{
    if (googleMap != null)
    {
        googleMap.clear();
        googleMap = null;
    }

    getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new MapFragment(), "mapFragment").commit();
}

OnFragmentLoadedCompleteListener.java

public interface OnFragmentLoadedCompleteListener
{
    public void onFragmentComplete();
}

onFragmentComplete() is executed, googleMap is not null and shown. But I can't draw markers on it. They just don't appear.

But when I don't dynamically add the map and embed it into the activity_main.xml within the RelativeLayout like this

<RelativeLayout
        android:id="@+id/fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

        <fragment
            xmlns:map="http://schemas.android.com/apk/res-auto"
            android:id="@+id/fragment_googlemap"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            class="com.androidmapsextensions.SupportMapFragment"
            map:cameraTargetLat="48.21167860510698"
            map:cameraTargetLng="16.365892895859423"
            map:cameraZoom="11"
            map:uiCompass="true"
            map:uiRotateGestures="true"
            map:uiScrollGestures="true"
            map:uiTiltGestures="true"
            map:uiZoomControls="true"
            map:uiZoomGestures="true" />
    </RelativeLayout>

and fetch the map like this without the listener, I can draw markers, that means they appear.

googleMap = ((SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.fragment_googlemap)).getExtendedMap();

That means drawing markers on the map only works when I directly embed the map into the xml of the MainActivity instead of added it dynamically as fragment. What's going on here. Where is the error?

Answer 1

As is often the case I found the solution on my own.

I have to keep a reference to my MapFragment I use to replace:

mapFragment = new MapFragment();
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, mapFragment).commit();

In onFragmentComplete() I have to invoke getChildFragmentManager() on this reference to obtain the "correct" GoogleMap.

googleMap = ((SupportMapFragment)mapFragment.getChildFragmentManager().findFragmentById(R.id.fragment_googlemap)).getExtendedMap();

This time it can be found by id as well (didn't work before), and drawing markers on this map works now.