سؤال

I have a MapFragment in my XML:

    <fragment
    android:id="@+id/mapFrag"
    android:name="com.google.android.gms.maps.MapFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_below="@+id/map_topbar"
    class="com.google.android.gms.maps.MapFragment" />

In my MapViewFragment I have a

     GoogleMap gmap;

in onCreate I do the following:

FragmentManager myFragmentManager = getFragmentManager();
SupportMapFragment mf =(SupportMapFragment)myFragmentManager.findFragmentById(R.id.mapFrag);
gmap = mf.getMap();

But I get a NullPointerException.

I've search and tried a lot of SO solutions but so far none have helped.

I've followed different tutorial:

http://android-er.blogspot.dk/2013/01/create-mapfragment-and-googlemap-using.html http://www.vogella.com/tutorials/AndroidGoogleMaps/article.html#maps_fragment

Where they use the same technique.

The log:

03-04 13:40:49.468: E/AndroidRuntime(32388): FATAL EXCEPTION: main
03-04 13:40:49.468: E/AndroidRuntime(32388): java.lang.NullPointerException
03-04 13:40:49.468: E/AndroidRuntime(32388):    at dk.adaptmobile.koegeapp.MapViewFragment.onCreate(MapViewFragment.java:56)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at android.support.v4.app.Fragment.performCreate(Fragment.java:1477)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:893)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:440)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at android.os.Handler.handleCallback(Handler.java:615)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at android.os.Handler.dispatchMessage(Handler.java:92)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at android.os.Looper.loop(Looper.java:137)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at android.app.ActivityThread.main(ActivityThread.java:4921)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at java.lang.reflect.Method.invokeNative(Native Method)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at java.lang.reflect.Method.invoke(Method.java:511)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
03-04 13:40:49.468: E/AndroidRuntime(32388):    at dalvik.system.NativeStart.main(Native Method)

Where line 56 is gmap = mf.getMap();

هل كانت مفيدة؟

المحلول 2

If you want to place a map inside of a fragment then I suggest you to use the MapView object in your layout instead of the MapFragment, here is a code that works for me:

The layout:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<com.google.android.gms.maps.MapView
    xmlns:map="http://schemas.android.com/apk/res-auto"
    android:id="@+id/mapview"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

</LinearLayout>

And the fragment itself:

public class MapFragment extends Fragment  {

private static final String TAG = MapFragment.class.getSimpleName();
private MapView mapView;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.new_mapview, container, false);

    // Gets the MapView from the XML layout and creates it
    mapView = (MapView) view.findViewById(R.id.mapview);
    mapView.onCreate(savedInstanceState);

    return view;
}


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


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

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

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

نصائح أخرى

Your XML does not match your Fragment code, you are creating a SupportMapFragment object when in your XML you have MapFragment:

Replace this:

<fragment
android:id="@+id/mapFrag"
android:name="com.google.android.gms.maps.MapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@+id/map_topbar"
class="com.google.android.gms.maps.MapFragment" />

with:

<fragment
android:id="@+id/mapFrag"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@+id/map_topbar"
class="com.google.android.gms.maps.SupportMapFragment" />

XML

<fragment
          android:id="@+id/map"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:name="com.google.android.gms.maps.MapFragment"/>

JAVA File

googleMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();

This works for me if your class extends Activity

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