Load ListView data from API with loading spinner using just Xamarin.Forms

Hello,

I am an Android and iPhone developer and I have just started developing with Xamarin and it is amazing! well done!
I would like to know if it is possible to download a JSON file or XML file from an API and show the data in a ListView without using Xamarin.iOS or Xamarin.Android just using Xamarin.Forms (Just creating the MainActivity o AppDelegate and loading the page from Xamarin.Forms). And I would like to show a loading spinner while the data is being downloaded. I know how to do it using Xamarin.iOS or Xamarin.Android but I want to know if it is possible to do it just with Xamarin.Forms and I don't find information about this.

Thanks!