Turn the marker depending on the direction of travel

Question

I have a marker on my Google Maps that looks like this:

When a user drives a car, I want to turn it based on its direction of movement. How can i achieve this? I probably should use the previous location and current location coordinates for the calculation, but I have no idea how to do this.

Answer 1

If you use GPS to search for a user, then the Location object that you get in onLocationChanged contains bearing .

If you have only two coordinates (for example, you only have coordinates from the network location provider), you can use Location.bearingTo() to calculate the reference coordinates of the two coordinates:

 Location prevLoc = ... ; Location newLoc = ... ; float bearing = prevLoc.bearingTo(newLoc) ; 

If you have a bearing, you can set the rotation of the marker using MarkerOptions.rotation() :

 mMap.addMarker(new MarkerOptions() .position(markerLatLng) .icon(BitmapDescriptorFactory.fromResource(R.drawable.map_marker)) .anchor(0.5f, 0.5f) .rotation(bearing) .flat(true)); 

You must set the anchor to the point you want to rotate, and this is also the point you want to see at the position set on the marker. (0.5, 0.5) is the center of the image.