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

Question

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.

Answer 1

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()