片段中的当前用户位置Google Map API v2（无效）

Question

I'm using the Google Maps for Android v2. I would like to display the current user location and zoom on it . Of course there are a lot of materials about that but most of them used Activity. In my case I used Fragment.

Here is the code in the Fragment which just show map: Can onyone check it and fix it?

public class MainFragment extends Fragment{

    private SupportMapFragment mSupportMapFragment;
    private GoogleMap mGoogleMap;

    private LocationManager mLocationManager;
    private LocationListener mLocationListener = new LocationListener() {
        @Override
        public void onLocationChanged(Location location) {
            getCurrentLocation();
        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {

        }

        @Override
        public void onProviderEnabled(String provider) {

        }

        @Override
        public void onProviderDisabled(String provider) {

        }
    };
    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        FragmentManager mFragmentManager = getChildFragmentManager();
        mSupportMapFragment = (SupportMapFragment) mFragmentManager.findFragmentById(R.id.map_container);
        if (mSupportMapFragment == null) {
            mSupportMapFragment = SupportMapFragment.newInstance();
            mFragmentManager.beginTransaction().replace(R.id.map_container, mSupportMapFragment).commit();
        }
    }

    void getCurrentLocation(){
        mLocationManager = (LocationManager)getActivity().getSystemService(Context.LOCATION_SERVICE);
        mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,mLocationListener);
        Location myLocation = mLocationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        //Location myLocation  = mGoogleMap.getMyLocation();
        if(myLocation!=null)
        {
            double dLatitude = myLocation.getLatitude();
            double dLongitude = myLocation.getLongitude();
            Log.i("APPLICATION"," : "+dLatitude);
            Log.i("APPLICATION"," : "+dLongitude);
            mGoogleMap.addMarker(new MarkerOptions().position(new LatLng(dLatitude, dLongitude)).title("My Location").snippet("Location"));
            mGoogleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(dLatitude, dLongitude), 8));

        }
        else
        {
            Toast.makeText(getActivity(), "Unable to fetch the current location", Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        try {
            Field childFragmentManager = Fragment.class.getDeclaredField("mChildFragmentManager");
            childFragmentManager.setAccessible(true);
            childFragmentManager.set(this, null);
        } catch (NoSuchFieldException e) {
            throw new RuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        }
    }
}

Answer 1

Have you tried the official documentation for obtaining location data? It's probably the first thing you want to check. Link

Try the following function.

void getCurrentLocation() {
    Location myLocation  = mMap.getMyLocation();
    if(myLocation!=null)
    {
        double dLatitude = myLocation.getLatitude();
        double dLongitude = myLocation.getLongitude();
        Log.i("APPLICATION"," : "+dLatitude);
        Log.i("APPLICATION"," : "+dLongitude);
        mMap.addMarker(new MarkerOptions().position(
                new LatLng(dLatitude, dLongitude)).title("My Location").icon(BitmapDescriptorFactory.fromBitmap(Utils.getBitmap("pointer_icon.png"))));
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(dLatitude, dLongitude), 8));

    }
    else
    {
        Toast.makeText(this, "Unable to fetch the current location", Toast.LENGTH_SHORT).show();
    }

}