androidgoogle-mapsgoogle-maps-markersgoogle-maps-api-2supportmapfragment

How to show multiple markers on MapFragment in Google Map API v2?


I am using Google Map API v2 in my application to show Maps.

I have followed all the steps, that is to be followed to enable Google Map in my application.

public class PinLocationOnMapView extends FragmentActivity {

    private double mLatitude = 0.0, mLongitude = 0.0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        SupportMapFragment fragment = SupportMapFragment.newInstance();
        getSupportFragmentManager().beginTransaction()
                .add(android.R.id.content, fragment).commit();
    }
}

If I use this code, it shows me map, but if I provide my latitude/longitude values, map tiles does not load, and I see only white tiles.

Following is the code written in onCreate() of above class:

 if (getIntent().getExtras() != null) {
            final Bundle bundle = getIntent().getBundleExtra("LOCATION");
            mLatitude = bundle.getDouble("LATITUDE");
            mLongitude = bundle.getDouble("LONGITUDE");
        } else {
            finish();
        }

        GoogleMapOptions options = new GoogleMapOptions();
        LatLng latLng = new LatLng(mLatitude, mLongitude);
        CameraPosition cameraPosition;// = new CameraPosition(latLng, 0, 0, 0);
        cameraPosition = CameraPosition.fromLatLngZoom(latLng, (float) 14.0);

        options.mapType(GoogleMap.MAP_TYPE_SATELLITE).camera(cameraPosition)
                .zoomControlsEnabled(true).zoomGesturesEnabled(true);

        SupportMapFragment fragment = SupportMapFragment.newInstance(options);
        getSupportFragmentManager().beginTransaction()
                .add(android.R.id.content, fragment).commit(); 

Also, I have a list of lat/long values. I want to show them on MapFragment, how to show multiple markers on MapFragment?

I tried with MapView and ItemizedOverlay, but it didn't work for me. I believe I have correctly created the SHA1 key to get the API key, because if that was wrong, I could not see map using MapFragment as well, but I can see that if I don't pass the lat/log value.


Solution

  • I do it like this to show car positions on the map with markers of different colors:

        private void addMarkersToMap() {
        mMap.clear();
        for (int i = 0; i < Cars.size(); i++) {         
                LatLng ll = new LatLng(Cars.get(i).getPos().getLat(), Cars.get(i).getPos().getLon());
                BitmapDescriptor bitmapMarker;
                switch (Cars.get(i).getState()) {
                case 0:
                    bitmapMarker = BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED);
                    Log.i(TAG, "RED");
                    break;
                case 1:
                    bitmapMarker = BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN);
                    Log.i(TAG, "GREEN");
                    break;
                case 2:
                    bitmapMarker = BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_ORANGE);
                    Log.i(TAG, "ORANGE");
                    break;
                default:
                    bitmapMarker = BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED);
                    Log.i(TAG, "DEFAULT");
                    break;
                }               
                mMarkers.add(mMap.addMarker(new MarkerOptions().position(ll).title(Cars.get(i).getName())
                        .snippet(getStateString(Cars.get(i).getState())).icon(bitmapMarker)));
    
                Log.i(TAG,"Car number "+i+"  was added " +mMarkers.get(mMarkers.size()-1).getId());
            }
        }
    
    }
    

    Cars is an ArrayList of custom objects and mMarkers is an ArrayList of markers.

    Note : You can show map in fragment like this:

    private GoogleMap mMap;
    ....
    
    private void setUpMapIfNeeded() {
        // Do a null check to confirm that we have not already instantiated the
        // map.
        if (mMap == null) {
            // Try to obtain the map from the SupportMapFragment.
            mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
            // Check if we were successful in obtaining the map.
            if (mMap != null) {
                setUpMap();
            }
        }
    }
    
    
    
    
    private void setUpMap() {
        // Hide the zoom controls as the button panel will cover it.
        mMap.getUiSettings().setZoomControlsEnabled(false);
    
        // Add lots of markers to the map.
        addMarkersToMap();
    
        // Setting an info window adapter allows us to change the both the
        // contents and look of the
        // info window.
        mMap.setInfoWindowAdapter(new CustomInfoWindowAdapter());
    
        // Set listeners for marker events. See the bottom of this class for
        // their behavior.
        mMap.setOnMarkerClickListener(this);
        mMap.setOnInfoWindowClickListener(this);
        mMap.setOnMarkerDragListener(this);
    
        // Pan to see all markers in view.
        // Cannot zoom to bounds until the map has a size.
        final View mapView = getSupportFragmentManager().findFragmentById(R.id.map).getView();
        if (mapView.getViewTreeObserver().isAlive()) {
            mapView.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
                @SuppressLint("NewApi")
                // We check which build version we are using.
                @Override
                public void onGlobalLayout() {
                    LatLngBounds.Builder bld = new LatLngBounds.Builder();
        for (int i = 0; i < mAvailableCars.size(); i++) {           
                LatLng ll = new LatLng(Cars.get(i).getPos().getLat(), Cars.get(i).getPos().getLon());
                bld.include(ll);            
        }
        LatLngBounds bounds = bld.build();          
        mMap.moveCamera(CameraUpdateFactory.newLatLngBounds(bounds, 70));
                    mapView.getViewTreeObserver().removeGlobalOnLayoutListener(this);
    
                }
            });
        }
    } 
    

    And just call setUpMapIfNeeded() in onCreate()