Xamarin Forms group controls without modifying layout - xamarin.forms

Question

I've got following view:
<ContentPage.Content>
<AbsoluteLayout HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand">
<StackLayout AbsoluteLayout.LayoutFlags="All" AbsoluteLayout.LayoutBounds="0,0,1,1">
<StackLayout VerticalOptions="CenterAndExpand" Margin="20, 0, 20, 0">
<StackLayout>
<Label Text="Login" HorizontalOptions="CenterAndExpand" />
<Entry Text="{Binding Login, Mode=OneWayToSource}"></Entry>
</StackLayout>
<StackLayout>
<Label Text="Hasło" HorizontalOptions="CenterAndExpand" />
<Entry IsPassword="True" Text="{Binding Password, Mode=TwoWay}"></Entry>
</StackLayout>
<Button Text="Zaloguj się" Command="{Binding SignInCommand}"></Button>
</StackLayout>
</StackLayout>
<BoxView AbsoluteLayout.LayoutFlags="All" AbsoluteLayout.LayoutBounds="0,0,1,1" BackgroundColor="Gray" Opacity="0.5" InputTransparent="false" IsVisible="{Binding IsBusy}" />
<ActivityIndicator IsRunning="{Binding IsBusy}" AbsoluteLayout.LayoutFlags="All" AbsoluteLayout.LayoutBounds="0,0,1,1" VerticalOptions="CenterAndExpand" HorizontalOptions="CenterAndExpand" />
</AbsoluteLayout>
</ContentPage.Content>
I want to move BoxView and ActivityIndicator to external control to make reusable component. The problem is that to achieve this I need to "group" these controls to obtain one child element.
The question is if is there any element I can use to group my controls, but which will not affect the way how controls are displayed? Alternatevlly which element I can use and how to still have effect of overlay over whole page and loading indicator?
I was trying to use AbsoluteLayout, StackLayout etc. but I couldn't position it to persist initial effect (overlay on whole page and loading indicator in the center with opacity = 1).

Answer 1

You can use DependencyService and reuse it in any page.
Check this tutorial.
There is also a working sample.