Partial implementation of SaveAndroid.cs

SaveAndroid.cs

public async Task SaveAndView(string fileName, String contentType, MemoryStream stream)
{
  //...

  if (file.Exists())
  {
      var path = Android.Net.Uri.FromFile(file);
      var extension = MimeTypeMap.GetFileExtensionFromUrl(Android.Net.Uri.FromFile(file).ToString());
      var mimeType = MimeTypeMap.Singleton.GetMimeTypeFromExtension(extension);

      var intent = new Intent(Intent.ActionView);
      intent.SetDataAndType(path, mimeType);
      Forms.Context.StartActivity(Intent.CreateChooser(intent, "Choose App"));
  }
}