Floating StackLayout xamarin forms - xaml

Question

I want in my content to have a 'StackLayout' fixed and floating where it will contain 4 'Button's.
My layout is assikm at the moment
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
Title="teste">
<Grid>
<ScrollView BackgroundColor="#ffffff" Padding="15" Grid.Row="0">
<StackLayout HorizontalOptions="Fill" VerticalOptions="FillAndExpand">
<Label Text="{Binding Titulo}" VerticalTextAlignment="Center" HorizontalTextAlignment="Center" TextColor="#38B6AB" FontSize="22" FontAttributes="Bold"/>
<Label Text="{Binding Data}" VerticalTextAlignment="Center" HorizontalTextAlignment="Center" TextColor="#5a5a5a" FontSize="18" FontAttributes="Bold"/>
<Image x:Name="imagen1" Source="{Binding ImageSource}" Aspect="AspectFit">
<Image.GestureRecognizers>
<TapGestureRecognizer
Tapped="OnTapped" />
</Image.GestureRecognizers>
</Image>
</StackLayout>
</ScrollView>
</Grid>
//-----Floating button----- //

Answer 1

The Grid can float things on top of other things by placing the item in the same row and column, like the following. I will note that, depending on how you place the Buttons, it might be a usability issue to place Buttons where the user is suppose to be scrolling.
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions> <!-- Multiple columns will allow even Button spacing, just set Grid.ColumnSpan on your ScrollView -->
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<ScrollView BackgroundColor="#ffffff"
Padding="15"
Grid.Row="0"
Grid.Column="0"
Grid.ColumnSpan="4">
<StackLayout HorizontalOptions="Fill"
VerticalOptions="FillAndExpand">
....
</StackLayout>
</ScrollView>
<Button Text="One"
Grid.Row="0"
Grid.Column="0"/>
<Button Text="Two"
Grid.Row="0"
Grid.Column="1"/>
<Button Text="Three"
Grid.Row="0"
Grid.Column="2"/>
<Button Text="Four"
Grid.Row="0"
Grid.Column="3"/>
</Grid>