问题
I have implemented an activity which adds MapFragment at run time. The MapFragment xml has static fragment and I'm trying to get add at run time. Also I found there are some issues in Lollipop adding the map fragment at runtime. Kindly check Issue raised and temporary solution
I have also given my codes below,
fragment_map.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".fragment.MapsFragment">
<fragment
android:id="@+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="appCreators.bloodfinder.activity.MapsActivity"/>
<include
android:id="@+id/layout"
layout="@layout/template_custom_spinner"/>
</FrameLayout>
MapsFragment.java
Implements onMapReadyCallback
public class MapsFragment extends SupportMapFragment implements OnMapReadyCallback
In onResume callback
@Override
public void onResume() {
super.onResume();
((SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map)).getMapAsync(this);
}
this always return me null and I have also tried,
((SupportMapFragment) getActivity().getSupportFragmentManager().findFragmentById(R.id.map)).getMapAsync(this);
this also return NullPointerException
MapsActivity.java
getSupportFragmentManager().beginTransaction().add(R.id.fragmentContainer, MapsFragment.newInstance()).commit();
I add this at onCreate method of Activity callback.
I'm not able to figure out why I'm still getting NullPointerException!
Some times I get Attempt to invoke interface method 'void com.google.maps.api.android.lib6.e.fl.o()' on a null object reference
Help will be appreciated!
UPDATE: Still not fixed I'm getting the following error. I looked into logs but no clue why this is happening.
Unable to resume activity {MapsActivity}: java.lang.NullPointerException: Attempt to invoke interface method 'void com.google.maps.api.android.lib6.e.fl.o()' on a null object reference
回答1:
I finally solved this issue for myself by observing the given answers in SO. I compared my code and the code in the answers. It seems to me that there is some confusion about this API and Google's implementation is very broad. I got this exception thrown repeatedly:
Attempt to invoke interface method 'void com.google.maps.api.android.lib6.e.fl.o()' on a null object reference
I still have no idea whats wrong with some of these implementations in SO questions that are getting the same exception, but this worked for me and it might work for someone else.
These are the the things you need to check:
Make sure you have both of these (I had only the api key meta-data)
<meta-data android:name="com.google.android.geo.API_KEY" android:value="@string/google_maps_key" /> <meta-data android:name="com.google.android.gms.version" android:value="@integer/google_play_services_version" />You have a fragment in xml like this with the class attribute being correct as below
<fragment android:id="@+id/google_map_fragment" class="com.google.android.gms.maps.SupportMapFragment" android:layout_width="match_parent" android:layout_height="match_parent"/>
In my case the map fragment is a child, inside another fragment.
This parent fragment apparently should not be a MapFragment or a SupportMapFragment. After changing it from SupportMapFragment to Fragment the map showed perfectly fine.
public class ParentFragment extends Fragment {
I left everything else as it was before but instead of getting the map in onCreateView I got it in onViewCreated like this:
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mapFragment = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.rewards_google_map_area);
if (mapFragment != null) {
LocationManager locationManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
if (locationManager != null && mapFragment.getMap() != null) {
googleMap=mapFragment.getMap();
//after this you do whatever you want with the map
}
}
}
I changed nothing else and I did not mess with the rootView or parentView. As you would see in the the answer from @Konstantin Loginov
Try it out and let me know.
回答2:
I've been struggling with similar issue a while ago.
The key was to getMap() in a proper moment, in onViewCreated() of the Fragment:
public class LocationFragment extends Fragment {
private SupportMapFragment locationMap;
private View rootView;
protected View getFragmentView() {
View view = getView();
if (view == null) {
view = rootView;
}
return view;
}
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View rootView = getFragmentView();
if (rootView != null) {
ViewGroup parent = (ViewGroup) rootView.getParent();
if (parent != null) {
parent.removeView(rootView);
}
}
try {
rootView = inflater.inflate(R.layout.fragment_signup_specify_location, container, false);
} catch (InflateException ex) {
Log.e(LOG_TAG, "Inflate Exception in onCreateView; Caused by map fragment", ex);
}
......
return getFragmentView();
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
locationMap = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.locationMap);
if (locationMap != null) {
LocationManager locationManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
if (locationManager != null && locationMap.getMap() != null) {
locationMap.getMap().setMyLocationEnabled(true);
}
}
}
}
And the XML for it looks like yours:
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<fragment
android:id="@+id/locationMap"
android:layout_above="@+id/locationLabelTextView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:name="com.google.android.gms.maps.SupportMapFragment" />
</FrameLayout>
Then, in onViewCreated() you can notify Activity, that your map-fragment is ready to use.
I hope, it helps
回答3:
In my case I use raw MapView statically in a Fragment's xml. The problem was that I had to move the call forwarding mMapView.onCreate(...) to onViewCreated(...) because in onCreate() mMapView is not yet inflated. If you don't use MapView then you should double-check in which moment you call getMap(). I must be after the internal MapView is inflated.
回答4:
UPDATE 2019
If you're still having this problems, try this :
Don't extend SupportMapFrangemt !
public class MyFragment extends Fragment {
private SupportMapFragment fragment;
private GoogleMap map;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.layout_with_map, container, false);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
FragmentManager fm = getChildFragmentManager();
fragment = (SupportMapFragment) fm.findFragmentById(R.id.map_container);
if (fragment == null) {
fragment = SupportMapFragment.newInstance();
fm.beginTransaction().replace(R.id.map_container, fragment).commit();
}
}
}
回答5:
If you use mapView just ensure that you called mapView.onCreate() before mapView.getMapAsync(). If you are using fragment and view still not initialized you are also able to call mapView.onCreate() in onViewCreated() method.
来源：https://stackoverflow.com/questions/34577869/mapfragment-causing-nullpointerexception-at-getmapasyncthis-method