向Google Map添加标记- Android (JAVA)

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapView;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

public class MainActivity extends AppCompatActivity implements OnMapReadyCallback {
    private MapView mapView;
    private GoogleMap googleMap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mapView = findViewById(R.id.mapView);
        mapView.onCreate(savedInstanceState);
        mapView.getMapAsync(this);
    }

    @Override
    public void onMapReady(GoogleMap map) {
        googleMap = map;
        googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(37.7749, -122.4194), 12));

        MarkerOptions markerOptions = new MarkerOptions()
                .position(new LatLng(37.7749, -122.4194))
                .title("San Francisco")
                .snippet("A beautiful city");

        googleMap.addMarker(markerOptions);
    }

    @Override
    public void onResume() {
        super.onResume();
        mapView.onResume();
    }

    @Override
    public void onPause() {
        super.onPause();
        mapView.onPause();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mapView.onDestroy();
    }

    @Override
    public void onLowMemory() {
        super.onLowMemory();
        mapView.onLowMemory();
    }
}