java - Google Maps: Current Location Marker (Period updates for GMaps)

Question

So I've been able to get periodic updates of my current location through the developer android page, making your app location aware. Now, whenever my location changes, I am able to get the latitude and longitude of that location. However, who do i implement this with Google Maps?

This line below implements a button on my map that finds my current location and places a blue dot/marker on it (does not receive periodic updates)

mMap.setMyLocationEnabled(true);

What should I put in my onLocationChanged() event in order for the blue dot to be updated with the new lat and long?

Answer 1

The blue dot and the precision circle are automatically managed by the map and you can't update it or change it's symbology. In fact, it's managed automatically using it's own LocationProvider so it gets the best location resolution available (you don't need to write code to update it, just enable it using mMap.setMyLocationEnabled(true);).

If you want to mock it's behaviour you can write something like this (you should disable the my location layer doing mMap.setMyLocationEnabled(false);):

private BitmapDescriptor markerDescriptor;
private int accuracyStrokeColor = Color.argb(255, 130, 182, 228);
private int accuracyFillColor = Color.argb(100, 130, 182, 228);

private Marker positionMarker;
private Circle accuracyCircle;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // ...

    markerDescriptor = BitmapDescriptorFactory.fromResource(R.drawable.yourmarkericon);
}

@Override
public void onLocationChanged(Location location) {
    double latitude = location.getLatitude();
    double longitude = location.getLongitude();
    float accuracy = location.getAccuracy();

    if (positionMarker != null) {
        positionMarker.remove();
    }
    final MarkerOptions positionMarkerOptions = new MarkerOptions()
            .position(new LatLng(latitude, longitude))
            .icon(markerDescriptor)
            .anchor(0.5f, 0.5f);
    positionMarker = mMap.addMarker(positionMarkerOptions);

    if (accuracyCircle != null) {
        accuracyCircle.remove();
    }
    final CircleOptions accuracyCircleOptions = new CircleOptions()
            .center(new LatLng(latitude, longitude))
            .radius(accuracy)
            .fillColor(accuracyFillColor)
            .strokeColor(accuracyStrokeColor)
            .strokeWidth(2.0f);
    accuracyCircle = mMap.addCircle(accuracyCircleOptions);
}