MapFragment 返回 Null

Question

我有一个活动和 MapFragment 类。我在 Activity 中创建了 MapFragment 对象。当我尝试获取 mapFragmentObject.getView() 时它返回 Null。但我已经创建了这样的 MapFragment

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    if (container == null) {
        return null;
    }

    view = inflater.inflate(R.layout.activity_main, container, false);

    mapView = ((MapView) view.findViewById(R.id.map));

    mapView.onCreate(savedInstanceState);
    setMapView();

    return view;
}

public void setMapView() {
    try {

        map = mapView.getMap();

        map.clear();

        LatLngBounds.Builder builder = new LatLngBounds.Builder();
        MapData mapData = MapData.getInstance();
        Double[][] latlang = mapData.getLatlang();
        String[] WONum = mapData.getWOnum();
        marker = new Marker[mapData.getLatlang().length];
        for (int i = 0; i < mapData.getLatlang().length; i++) {
            this.marker[i] = map.addMarker(new MarkerOptions()
                    .position(new LatLng(latlang[i][0], latlang[i][1]))
                    .title(" ").snippet(" " + WONum[i] + "\n"));
            builder.include(this.marker[i].getPosition());
        }

        LatLngBounds bounds = builder.build();

        CameraUpdate cu = CameraUpdateFactory.newLatLngBounds(bounds, 60,
                60, 1);
        map.animateCamera(cu);

        map.setOnCameraChangeListener(new OnCameraChangeListener() {

            @Override
            public void onCameraChange(CameraPosition position) {

                if (position.zoom > 12.0f) {
                    map.animateCamera(CameraUpdateFactory.zoomTo(12.0f));
                } else if (position.zoom < 2.0f) {
                    map.animateCamera(CameraUpdateFactory.zoomTo(4.0f));
                }
            }
        });

    } catch (Exception e) {

    }

}

我从 Activity 调用就像 在 OnCreate 中

WOLocator locator = new WOLocator();
getFragmentManager().beginTransaction().add(locator, "Map").commit();
setContentView(getFragmentManager().findFragmentByTag("Map").getView());

我做错了什么？

Answer 1

这实际上也是我遇到的一个问题，问题是由于地图在您当前尝试请求它时没有初始化。映射过程比标准视图设置需要更长的时间。

您可以设置一些侦听器在准备就绪后触发，但我发现使用地图片段的 onActivityCreated 函数非常可靠（我的扩展了 SupportMapFragment）。

因此，对于您的示例，我会尝试将您的 setMapView() 函数调用移动到片段的 onActivityCreated 函数。

希望这会有所帮助。

Answer 2

in layout activity_main.xml

     <com.google.android.gms.maps.MapView
                android:id="@+id/mapEditView"
                android:name="com.google.android.gms.maps.MapFragment"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginRight="10dp" />

在java文件中

MapView mapView;
GoogleMap map;
LatLng CENTER = null;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    View view = null;
    view = inflater.inflate(R.layout.activity_main, container,
                false);
    CENTER = new LatLng(latitudeDoubleValue, longitudeDoubleValue);

    mapView = (MapView) view.findViewById(R.id.mapEditView);
    mapView.onCreate(savedInstanceState);

   setMapView();
}



 private void setMapView() {
    if (mapView != null) {
        locationManager = ((LocationManager) getActivity()
                .getSystemService(Context.LOCATION_SERVICE));

        locListener = new MyLocationListener();
        Boolean localBoolean = Boolean.valueOf(locationManager
                .isProviderEnabled("network"));

        if (localBoolean.booleanValue()) {

            CENTER = new LatLng(latitudeDouble, longitudeDouble);
            GetCityNameFromLatitudeLongitude getCityName = new GetCityNameFromLatitudeLongitude(
                    getActivity());
            locationString = getCityName.getCityNameFromLatitudeLongitude(
                    CENTER.latitude, CENTER.longitude);
        } else {

        }
        map = mapView.getMap();
        if (map == null) {
            Log.d("----------->>>",
                    "Map Fragment Not Found or no Map in it!!");
            return;
        }

        map.clear();
        try {
            map.addMarker(new MarkerOptions().position(CENTER)
                    .title(locationString).snippet(""));
        } catch (Exception e) {
            e.printStackTrace();
        }
        map.setIndoorEnabled(true);

        map.setMyLocationEnabled(true);

        map.moveCamera(CameraUpdateFactory.zoomTo(5));
        if (CENTER != null) {
            map.animateCamera(CameraUpdateFactory.newLatLng(CENTER), 1750,
                    null);
        }
        // add circle
        CircleOptions circle = new

        CircleOptions();

        circle.center(CENTER).fillColor(Color.BLUE).radius(10);

        map.addCircle(circle);
        // map.setMapType(GoogleMap.MAP_TYPE_SATELLITE);

        map.setMapType(GoogleMap.MAP_TYPE_NORMAL);
        map.setOnMapClickListener(this);
    }
}