[Android] Add Platform Specific features for setting TabbedPage swipe paging and OffscreenPageLimit (#409)

* [Android] Add Platform Specific feature for setting TabbedPage swipe paging

* [Android] Add Platform Specific feature for OffscreenPageLimit

* Update docs

1 files changed, 72 insertions, 0 deletions

diff --git a/Xamarin.Forms.Controls/GalleryPages/PlatformSpecificsGalleries/TabbedPageAndroid.cs b/Xamarin.Forms.Controls/GalleryPages/PlatformSpecificsGalleries/TabbedPageAndroid.cs
new file mode 100644
index 00000000..ab1904a4
--- /dev/null
+++ b/Xamarin.Forms.Controls/GalleryPages/PlatformSpecificsGalleries/TabbedPageAndroid.cs
@@ -0,0 +1,72 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Input;
+using Xamarin.Forms.PlatformConfiguration;
+using Xamarin.Forms.PlatformConfiguration.AndroidSpecific;
+
+namespace Xamarin.Forms.Controls.GalleryPages.PlatformSpecificsGalleries
+{
+	public class TabbedPageAndroid : TabbedPage
+	{
+		public TabbedPageAndroid(ICommand restore)
+		{
+			Children.Add(CreateFirstPage(restore));
+			Children.Add(CreateAdditonalPage());
+			Children.Add(CreateAdditonalPage());
+			Children.Add(CreateAdditonalPage());
+			Children.Add(CreateAdditonalPage());
+			On<Android>().SetOffscreenPageLimitProperty(2);
+		}
+
+		ContentPage CreateFirstPage(ICommand restore)
+		{
+			var page = new ContentPage { Title = "Content Page Title" };
+			var offscreenPageLimit = new Label();
+			var content = new StackLayout
+			{
+				VerticalOptions = LayoutOptions.Fill,
+				HorizontalOptions = LayoutOptions.Fill,
+				Children =
+				{
+					new Button
+					{
+						Text = "Click to Toggle Swipe Paging",
+						Command = new Command(() => On<Android>().SetIsSwipePagingEnabled(!On<Android>().IsSwipePagingEnabled()))
+					},
+					offscreenPageLimit
+				}
+			};
+
+			var restoreButton = new Button { Text = "Back To Gallery" };
+			restoreButton.Clicked += (sender, args) => restore.Execute(null);
+			content.Children.Add(restoreButton);
+
+			page.Content = content;
+
+			return page;
+		}
+
+		static Page CreateAdditonalPage()
+		{
+			var cp = new ContentPage { Title = "Additional Page" };
+
+			cp.Content = new StackLayout
+			{
+				VerticalOptions = LayoutOptions.Fill,
+				HorizontalOptions = LayoutOptions.Fill,
+				Children =
+				{
+					new Entry
+					{
+						Placeholder = "Enter some text"
+					}
+				}
+			};
+
+			return cp;
+		}
+	}
+}