java - Android:将谷歌地图放入 fragment 中

Question

我花了一段时间试图让它发挥作用，但在每个教程中我总是陷入困境。简而言之，我正在尝试制作一个选项卡式应用程序，其中选项卡之一是谷歌地图。

我已经修复了所有常见错误:

我已经通过 SDK 下载了所有相关内容。
我有一个 API key 。
我已将编译 com.google.android.gms:play-services:7.5.0 添加到我的依赖项中。

我正在尝试关注this code ，但我不断收到错误。

我从 logcat 收到错误:

07-06 13:46:20.046  17948-17948/dolphin.dolphinapp E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: dolphin.dolphinapp, PID: 17948
    java.lang.NullPointerException: IBitmapDescriptorFactory is not initialized
            at com.google.android.gms.common.internal.zzu.zzb(Unknown Source)
            at com.google.android.gms.maps.model.BitmapDescriptorFactory.zzvH(Unknown Source)
            at com.google.android.gms.maps.model.BitmapDescriptorFactory.defaultMarker(Unknown Source)
            at dolphin.dolphinapp.MainActivity$MapFragment.onCreateView(MainActivity.java:655)
            at android.support.v4.app.Fragment.performCreateView(Fragment.java:1789)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:955)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1138)
            at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:740)
            at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1501)
            at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:490)
            at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
            at android.support.v4.view.ViewPager.populate(ViewPager.java:1105)
            at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:551)
            at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:513)
            at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:494)
            at dolphin.dolphinapp.MainActivity.onTabSelected(MainActivity.java:152)
            at android.support.v7.internal.app.WindowDecorActionBar.selectTab(WindowDecorActionBar.java:640)
            at android.support.v7.internal.app.WindowDecorActionBar$TabImpl.select(WindowDecorActionBar.java:1224)
            at android.support.v7.internal.widget.ScrollingTabContainerView$TabClickListener.onClick(ScrollingTabContainerView.java:568)
            at android.view.View.performClick(View.java:4780)
            at android.view.View$PerformClick.run(View.java:19866)
            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:5257)
            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:903)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

显然要解决这个问题，请编写MapsInitializer.initialize(getActivity().getApplicationContext());，但这已经在我复制的代码中了。

这是我的 Java 代码:

public class MapFragment extends Fragment {

        MapView mMapView;
        private GoogleMap googleMap;

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            // inflat and return the layout
            View v = inflater.inflate(R.layout.fragment_location_info, container,
                    false);

            mMapView = (MapView) v.findViewById(R.id.mapView);
            mMapView.onCreate(savedInstanceState);

            mMapView.onResume();// needed to get the map to display immediately

            try {
                MapsInitializer.initialize(getActivity().getApplicationContext());
            } catch (Exception e) {
                e.printStackTrace();
            }

            MapsInitializer.initialize(getApplicationContext());

            googleMap = mMapView.getMap();
            // latitude and longitude
            double latitude = 17.385044;
            double longitude = 78.486671;


            // create marker
            MarkerOptions marker = new MarkerOptions().position(new LatLng(latitude, longitude)).title("Hello Maps");

            // Changing marker icon
            marker.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_ROSE));

            // adding marker
            googleMap.addMarker(marker);

            CameraPosition cameraPosition = new CameraPosition.Builder().target(new LatLng(17.385044, 78.486671)).zoom(12).build();

            googleMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));

            // Perform any camera updates here
            return v;
        }

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

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

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

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

我的 XML 文件:

<?xml version="1.0" encoding="utf-8"?>
<com.google.android.gms.maps.MapView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/mapView"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

请让我知道我做错了什么

Answer 1

您应该在 onCreateView 中调用 mMapView.getMapAsync()，然后在您实现的 onMapReady 回调中执行 MapsInitializer.initialize(this.context);

mMapView.getMapAsync(new OnMapReadyCallback() {
    @Override
    public void onMapReady(GoogleMap googleMap) {
           MapsInitializer.initialize(getApplicationContext());
        // latitude and longitude
        double latitude = 17.385044;
        double longitude = 78.486671;


        // create marker
        MarkerOptions marker = new MarkerOptions().position(new LatLng(latitude, longitude)).title("Hello Maps");

        // Changing marker icon
        marker.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_ROSE));             
    }
});