当我尝试在片段上显示地图时，它返回空指针异常。我已将所有权限添加到清单中。我将片段文件附加为其XML文件和log cat
Chatffragment.java
public class ChatFragment extends Fragment{ // Google Map private GoogleMap googleMap; public ChatFragment() { // Required empty public constructor } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View chatfrag = inflater.inflate(R.layout.chatfragment, container, false); try { // Loading map initilizeMap(); } catch (Exception e) { e.printStackTrace(); } return chatfrag; } /** * function to load map. If map is not created it will create it for you * */ private void initilizeMap() { if (googleMap == null) { SupportMapFragment mapFrag = (SupportMapFragment) getActivity().getSupportFragmentManager().findFragmentById(R.id.map); googleMap = mapFrag.getMap(); googleMap.setMyLocationEnabled(true); // check if map is created successfully or not if (googleMap == null) { Toast.makeText(getActivity(), "Sorry! unable to create maps", Toast.LENGTH_SHORT) .show(); } } } @Override public void onResume() { super.onResume(); initilizeMap(); } }
其XML
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" > <fragment android:id="@+id/map" android:name="com.google.android.gms.maps.SupportMapFragment" android:layout_width="match_parent" android:layout_height="match_parent"/> </RelativeLayout>
LOGCAT
04-05 09:12:22.075 26987-26987/com.example.vikrant.safeshelter E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.vikrant.safeshelter, PID: 26987 java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.GoogleMap com.google.android.gms.maps.SupportMapFragment.getMap()' on a null object reference at com.example.vikrant.safeshelter.ChatFragment.initilizeMap(ChatFragment.java:55) at com.example.vikrant.safeshelter.ChatFragment.onResume(ChatFragment.java:70) at android.support.v4.app.Fragment.performResume(Fragment.java:2020) at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1107) at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1252) at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738) at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1617) at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:570) at android.support.v4.app.FragmentStatePagerAdapter.finishUpdate(FragmentStatePagerAdapter.java:164) at android.support.v4.view.ViewPager.populate(ViewPager.java:1177) at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:608) at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:570) at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:551) at android.support.design.widget.TabLayout$ViewPagerOnTabSelectedListener.onTabSelected(TabLayout.java:1627) at android.support.design.widget.TabLayout.selectTab(TabLayout.java:837) at android.support.design.widget.TabLayout.selectTab(TabLayout.java:809) at android.support.design.widget.TabLayout$Tab.select(TabLayout.java:1077) at android.support.design.widget.TabLayout$1.onClick(TabLayout.java:643) at android.view.View.performClick(View.java:4759) at android.view.View$PerformClick.run(View.java:19770) at android.os.Handler.handleCallback(Handler.java:739) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5234) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:909) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:704)
第55和70行是googleMap = mapFrag.getMap（）; initilizeMap（）;
您必须等到地图加载完毕…。
public class ChatFragment extends Fragment implements OnMapReadyCallback { private void initilizeMap() { //SupportMapFragment mapFragment = (SupportMapFragment) fragmentManager.findFragmentById(R.id.map); SupportMapFragment mapFrag = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map); mapFrag.getMapAsync(this); } @Override public void onMapReady(final GoogleMap map) { googleMap = map; //Do other stuff.......... } }
编辑
SupportMapFragment mapFrag = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map);
检查编辑代码，使用ChildFragmentManager。
