片段内的Android MapView Map V2

Question

I have been trying to get my Maps working, I have FragmentTabHost atm only contains 3 tabs. In my Maps tab, it should load the google map fragment and zoom into the users location however it just loads the map but does not do the zoom in method. Also is there I fix if there is a Binrary XML file due to map ID duplicates it crashes the app when I return back to the Maps tab.

Another question is that what method can I take to be able to load the maptab asynchronously.

public class Maps extends Fragment {

private GoogleMap googleMap;
MapView mapView;


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    View view = inflater.inflate(R.layout.fragment_maps, container, false);

    mapView = (MapView) view.findViewById(R.id.mapview);
    mapView.onCreate(savedInstanceState);

    // Gets to GoogleMap from the MapView and does initialization stuff
    googleMap = mapView.getMap();
    MapsInitializer.initialize(this.getActivity());
    return view;
}

public void onActivityCreate(Bundle savedInstanceState){
    super.onActivityCreated(savedInstanceState);
    setUpMapIfNeeded();
}

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

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

private void setUpMapIfNeeded() {
    // Do a null check to confirm that we have not already instantiated the map.
    if (googleMap == null) {
        // Try to obtain the map from the SupportMapFragment.
        googleMap = ((SupportMapFragment) getActivity().getSupportFragmentManager().findFragmentById(R.id.mapview))
                .getMap();
        // Check if we were successful in obtaining the map.
        if (googleMap != null) {
            executeMap();
        }
    }
}

private void executeMap() {
    googleMap.setMyLocationEnabled(true);
    googleMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));

    //Get location services from Google services and choose the best fit through criteria
    LocationManager locationMan = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
    Criteria bestFit = new Criteria();

    //Get name of best provider
    String provider = locationMan.getBestProvider(bestFit, true);
    //Get Location
    Location myLocation = locationMan.getLastKnownLocation(provider);

    //Get long and lat, create an object marker
    double latitude = myLocation.getLatitude();
    double longitude = myLocation.getLongitude();
    LatLng position = new LatLng(latitude, longitude);

    //Zoom into current location
    googleMap.animateCamera(CameraUpdateFactory.newLatLng(position));
    googleMap.animateCamera(CameraUpdateFactory.zoomTo(18));
    googleMap.addMarker(new MarkerOptions().position(new LatLng(latitude, longitude)).title("You are here"));
}

}

Why does it not execute setupmaifneeded(); ?

Answer 1

For the first issue : try to use following method to zoom the camera to user's location :

private void centerMapOnMyLocation() {

    map.setMyLocationEnabled(true);

    location = map.getMyLocation();

    if (location != null) {
        myLocation = new LatLng(location.getLatitude(),
                location.getLongitude());
    }
    map.animateCamera(CameraUpdateFactory.newLatLngZoom(myLocation,
            Constants.MAP_ZOOM));
} 

For the second issue : what do you mean by load the maptab asynchronously ? Do you need to read data form database ? My suggest is you can add a splashScreen on your app to wait a moment let the data to be loaded.

Answer 2

The app crash is happening because of the fact that you are not using interfaces in order to communicate in between the fragment. Right now they are tightly coupled so there is a memory leakage. Please refer to this guide to know more about the inter fragment communication in android. For code implementation refer to this guide.

Hope that helps!!