Draw path between two locations in google maps v2 xamarin android

In brief: Google maps android API V2 allows the developer to integrate and customize the google map look and feel. This API handles the access to Google Maps Server,fetching map data ,display and response to map gesture.
[read more : https://developers.google.com/maps/documentation/android/intro]
Here I will write the steps to draw path between two geo-location in android xamarin.

Android.Gms.Maps.MapFragment.Map is obsolete deprecated xamarin android

It is always not recommended to use Obsolete API, as it involves risk of non-functioning at any point of time. In this post let us see the alternate for Google map obsolete api MapFragment.Map.

In  previous post i explained Integration of google map v2 in xamarin android,How to use Google geocode and reverse geocode api in xamarin.android, How to use Google Place API with Autocomplete in Xamarin Android,Integrating Google Account in Xamarin.Android, How to customize AlertDialog in xamarin.Android.

Using the "Map" Property of the "MapFragment" marks with a warning "Android.Gms.Maps.MapFragment.Map is obsolete deprecated". 
Instead need to make use of the method GetMapAsync(),which expects implementation of callback object of type IOnMapReadyCallback.

Login by google account integration for Xamarin.Android and Xamarin.iOS

Brief: 
Google Account integration to the app, helps for the user authentication using their existing Google account and fetch profile information like email id,name and profile pic etc.
UPDATE: Mar 10,2017: It seems that google has been stopped webview approach for native applications. You can refer the solution provided by the xamarin doc.