private void Adapter_DeleteItemClick(object sender, int position)
 {
     using (var diag = new global::Android.Support.V7.App.AlertDialog.Builder(this))
     {
         diag.SetTitle(Resource.String.deleteTitle)
         .SetMessage(Resource.String.deleteMessage)
         .SetNegativeButton(Resource.String.dialog_cancel, (a, e) => { })
         .SetPositiveButton(Resource.String.DeleteBtn, (a, b) =>
         {
             position--;
             adapter.Collection.Activities.RemoveAt(position);
             adapter.NotifyDataSetChanged();
             SaveProgress();
         })
         .Show();
     }
 }
 protected override void OnResume()
 {
     SaveProgress();
     adapter?.NotifyDataSetChanged();
     base.OnResume();
 }