java - onLocationChanged() 中的 map.moveCamera

Question

我遇到了这样的问题:我在我的应用程序中的 Fragment 中使用 GoogleMaps map ，并且在调用 onLocationChanged 方法时它会中断。 问题是这一行

mMap.moveCamera(CameraUpdatesFactory.newLatLngZoom(position, 15);

可能是因为它找不到 mMap 或者我不知道。 这是代码部分:

public class home extends AppCompatActivity implements OnMapReadyCallback, GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener{

GoogleMap mMap;
Marker marker;

private void checkAndStartLocationUpdate() {
    if (permissionGranted && googleApiClientReady) {
        Log.d("MainActivity", "Start updating location");
        LocationRequest mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(10000);
        mLocationRequest.setFastestInterval(5000);
        mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
        try {

            LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);

            lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);

            SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
            mapFragment.getMapAsync(this);

            location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);

        } catch (SecurityException e) {
            e.printStackTrace();
        }
    }
}

public void onLocationChanged(Location location) {

    Log.d("MainActivity", "Location update received: " + location.toString());

    latitude = location.getLatitude();
    longitude = location.getLongitude();

    Log.d("MainActivity", longitude + " " + latitude);

    LatLng position = new LatLng(longitude, latitude);
    marker.setPosition(position);
    mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(position, 15));

}

Answer 1

你可以做任何一个

@Override
public void onMapReady(GoogleMap googleMap)
{
    mMap = googleMap;

    // Tika
    // Tika
    // Tika
}

并改变

mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(position, 15));

至

if(mMap != null)
   mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(position, 15));

或者您可以简单地调用

    LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);

onMapReady内部之后mMap = googleMap;