[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

3 files changed, 77 insertions, 1 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;
+		}
+	}
+}
diff --git a/Xamarin.Forms.Controls/GalleryPages/PlatformSpecificsGallery.cs b/Xamarin.Forms.Controls/GalleryPages/PlatformSpecificsGallery.cs
index 67465da1..1bca68bb 100644
--- a/Xamarin.Forms.Controls/GalleryPages/PlatformSpecificsGallery.cs
+++ b/Xamarin.Forms.Controls/GalleryPages/PlatformSpecificsGallery.cs
@@ -14,6 +14,7 @@ namespace Xamarin.Forms.Controls
 			var navpageiOSButton = new Button() { Text = "Navigation Page (iOS)" };
 			var viselemiOSButton = new Button() { Text = "Visual Element (iOS)" };
 			var appAndroidButton = new Button() { Text = "Application (Android)" };
+			var tbAndroidButton = new Button { Text = "TabbedPage (Android)" };
 
 			mdpWindowsButton.Clicked += (sender, args) => { SetRoot(new MasterDetailPageWindows(new Command(RestoreOriginal))); };
 			npWindowsButton.Clicked += (sender, args) => { SetRoot(new NavigationPageWindows(new Command(RestoreOriginal))); };
@@ -21,10 +22,12 @@ namespace Xamarin.Forms.Controls
 			navpageiOSButton.Clicked += (sender, args) => { SetRoot(NavigationPageiOS.Create(new Command(RestoreOriginal))); };
 			viselemiOSButton.Clicked += (sender, args) => { SetRoot(new VisualElementiOS(new Command(RestoreOriginal))); };
 			appAndroidButton.Clicked += (sender, args) => { SetRoot(new ApplicationAndroid(new Command(RestoreOriginal))); };
+			tbAndroidButton.Clicked += (sender, args) => { SetRoot(new TabbedPageAndroid(new Command(RestoreOriginal))); };
+			
 
 			Content = new StackLayout
 			{
-				Children = { mdpWindowsButton, npWindowsButton, tbWindowsButton, navpageiOSButton, viselemiOSButton, appAndroidButton }
+				Children = { mdpWindowsButton, npWindowsButton, tbWindowsButton, navpageiOSButton, viselemiOSButton, appAndroidButton, tbAndroidButton }
 			};
 		}
 
diff --git a/Xamarin.Forms.Controls/Xamarin.Forms.Controls.csproj b/Xamarin.Forms.Controls/Xamarin.Forms.Controls.csproj
index b85020ba..b1568398 100644
--- a/Xamarin.Forms.Controls/Xamarin.Forms.Controls.csproj
+++ b/Xamarin.Forms.Controls/Xamarin.Forms.Controls.csproj
@@ -106,6 +106,7 @@
     <Compile Include="GalleryPages\PlatformSpecificsGalleries\NavigationPageiOS.cs" />
     <Compile Include="GalleryPages\PlatformSpecificsGalleries\NavigationPageWindows.cs" />
     <Compile Include="GalleryPages\PlatformSpecificsGalleries\ApplicationAndroid.cs" />
+    <Compile Include="GalleryPages\PlatformSpecificsGalleries\TabbedPageAndroid.cs" />
     <Compile Include="GalleryPages\PlatformSpecificsGalleries\TabbedPageWindows.cs" />
     <Compile Include="GalleryPages\PlatformSpecificsGalleries\VisualElementiOS.cs" />
     <Compile Include="GalleryPages\PlatformSpecificsGalleries\WindowsPlatformSpecificsGalleryHelpers.cs" />