我的XML中有一个MapFragment:
<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" />
在我的 MapViewFragment 中,我有一个
GoogleMap gmap;
在onCreate
我执行以下操作:
FragmentManager myFragmentManager = getFragmentManager();
SupportMapFragment mf =(SupportMapFragment)myFragmentManager.findFragmentById(R.id.mapFrag);
gmap = mf.getMap();
但是我得到了 NullPointerException 。
我已经搜索并尝试了很多SO解决方案,但到目前为止还没有人帮助过。
我遵循了不同的教程:
http://android-er.blogspot.dk/2013/01/create-mapfragment-and-googlemap-using.html http://www.vogella.com/tutorials/AndroidGoogleMaps/article.html#maps_fragment
他们使用相同的技术。
日志:
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)
其中第56行是gmap = mf.getMap();
答案 0 :(得分:2)
您的XML与您的片段代码不匹配,您在XML格式SupportMapFragment
时创建了MapFragment
对象:
替换它:
<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" />
使用:
<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" />
答案 1 :(得分:1)
如果你想在一个片段中放置一个地图,我建议你在你的布局中使用MapView
对象而不是MapFragment
,这是一个适合我的代码:
布局:
<?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>
片段本身:
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();
}
}
答案 2 :(得分:0)
<强> XML 强>
<fragment
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:name="com.google.android.gms.maps.MapFragment"/>
JAVA文件
googleMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
如果您的课程延伸Activity