Question

我的代码完全没问题，我想在应用程序打开后立即在地图上获取用户位置。但该应用程序崩溃了。此外，该程序设置为更新位置并在其更改时添加标记，该标记也不起作用。这是代码

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback, LocationListener {

    private GoogleMap mMap;
    LocationManager locationManager;
    String provider;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
        locationManager = (LocationManager)    getSystemService(Context.LOCATION_SERVICE);
        provider = locationManager.getBestProvider(new Criteria(), false);

    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        Location location= locationManager.getLastKnownLocation(provider);
        double lat =location.getLatitude();
        double lng =location.getLongitude();
        mMap.addMarker(new MarkerOptions().position(new LatLng(lat, lng)).title("Marker"));

        // Add a marker and move the camera

    }

    @Override
    public void onLocationChanged(Location location) {
        Double lat = location.getLatitude();
        Double lng = location.getLongitude();
        mMap.addMarker(new MarkerOptions().position(new LatLng(lat, lng)).title("Marker"));
        mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(lat, lng), 10));
        Log.i("Latitude", lat.toString());

    }

Answer 1

试试这个。如果位置在缓存中，则getLastKnownLocation返回，否则返回null 在那里添加支票

 if(location!=null)
 {
 double lat =location.getLatitude();
double lng =location.getLongitude();
mMap.addMarker(new MarkerOptions().position(new LatLng(lat,lng)).title("Marker"));
}

2解决方案使用google play services fusedlocation api以便更好地管理位置，请参阅此处http://coderzpassion.com/android-location-using-google-play-services/

3尝试使用addMarker

public void drawMarker(double lat,double lon)
{
    if (mMap != null) {
        MarkerOptions marker = new MarkerOptions().position(new LatLng(lat, lon)).title(" Maps Tutorial").snippet("Android Ruler");
        marker.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
 // Moving Camera to a Location with animation
        CameraPosition cameraPosition = new CameraPosition.Builder().target(new LatLng(latitude, longitude)).zoom(12).build();
        mMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
        mMap.addMarker(marker);
    }
}

有关详细信息，请参阅此处http://coderzpassion.com/android-google-maps-v2-tutorial-with-markers/

试图在Android的地图上获取用户位置

1 个答案: