MapFragment返回空值

Question

我有一个activity和MapFragment类。我在Activity.When中创建了MapFragment对象，我尝试获取mapFragmentObject.getView()，它返回Null.But。我创建了MapFragment，如下所示

@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) {

    }

}

我在Activity里打电话，就像在OnCreate里一样

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，这个问题是由于地图在你当前试图请求它的时候没有初始化而引起的。映射过程比标准视图设置需要更长的时间。

有一些监听器可以设置为一旦准备好就触发，但我发现使用映射片段(我的扩展了SupportMapFragment)的onActivityCreated函数非常可靠。

因此，对于您的示例，我将尝试将您的setMapView()函数调用移动到您的片段的onActivityCreated函数。

希望这能有所帮助。

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);
    }
}