MainPage.xaml

<?xml version="1.0" encoding="utf-8"?>
<ContentPage Title="Xamarin Galleries" 
             xmlns="http://xamarin.com/schemas/2014/forms" 
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
             xmlns:local="clr-namespace:XamarinGalleries" 
             x:Class="XamarinGalleries.MainPage">
    <StackLayout VerticalOptions="Center">
        <Button Text="Two Columns Gallery" Clicked="Handle_Clicked"/>
        <Button Text="Three Columns Gallery" Clicked="Handle_Clicked_1"/>
        <Button Text="Auto Height Gallery" Clicked="Handle_Clicked_2"/>
        <Button Text="Standart Height Gallery" Clicked="Handle_Clicked_3"/>
        <Button Text="Vertical Gallery" Clicked="Handle_Clicked_4"/>
        <Button Text="Horizontal Gallery" Clicked="Handle_Clicked_5"/>
    </StackLayout>
</ContentPage>