Refactored platform navigation methods

Source/Xamarin/Prism.Forms/Navigation/INavigationServiceExtensions.cs

@@ -19,7 +19,7 @@ public static class INavigationServiceExtensions
         /// <returns>If <c>true</c> a go back operation was successful. If <c>false</c> the go back operation failed.</returns>
         public static Task<INavigationResult> GoBackAsync(this INavigationService navigationService, INavigationParameters parameters = null, bool? useModalNavigation = null, bool animated = true)
         {
-            return ((INavigateInternal)navigationService).GoBackInternal(parameters, useModalNavigation, animated);
+            return ((IPlatformNavigationService)navigationService).GoBackAsync(parameters, useModalNavigation, animated);
         }
 
         /// <summary>
@@ -30,7 +30,7 @@ public static Task<INavigationResult> GoBackAsync(this INavigationService naviga
         /// <remarks>Only works when called from a View within a NavigationPage</remarks>
         public static Task<INavigationResult> GoBackToRootAsync(this INavigationService navigationService, INavigationParameters parameters = null)
         {
-            return ((INavigateInternal)navigationService).GoBackToRootInternal(parameters);
+            return ((IPlatformNavigationService)navigationService).GoBackToRootAsync(parameters);
         }
 
         /// <summary>
@@ -42,7 +42,7 @@ public static Task<INavigationResult> GoBackToRootAsync(this INavigationService
         /// <param name="animated">If <c>true</c> the transition is animated, if <c>false</c> there is no animation on transition.</param>
         public static Task<INavigationResult> NavigateAsync(this INavigationService navigationService, string name, INavigationParameters parameters = null, bool? useModalNavigation = null, bool animated = true)
         {
-            return ((INavigateInternal)navigationService).NavigateInternal(name, parameters, useModalNavigation, animated);
+            return ((IPlatformNavigationService)navigationService).NavigateAsync(name, parameters, useModalNavigation, animated);
         }
 
         /// <summary>
@@ -58,7 +58,7 @@ public static Task<INavigationResult> NavigateAsync(this INavigationService navi
         /// </example>
         public static Task<INavigationResult> NavigateAsync(this INavigationService navigationService, Uri uri, INavigationParameters parameters = null, bool? useModalNavigation = null, bool animated = true)
         {
-            return ((INavigateInternal)navigationService).NavigateInternal(uri, parameters, useModalNavigation, animated);
+            return ((IPlatformNavigationService)navigationService).NavigateAsync(uri, parameters, useModalNavigation, animated);
         }
 
         /// <summary>

Source/Xamarin/Prism.Forms/Navigation/IPlatformNavigationService.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Threading.Tasks;
+
+namespace Prism.Navigation
+{
+    public interface IPlatformNavigationService
+    {
+        Task<INavigationResult> GoBackAsync(INavigationParameters parameters, bool? useModalNavigation, bool animated);
+
+        Task<INavigationResult> GoBackToRootAsync(INavigationParameters parameters);
+
+        Task<INavigationResult> NavigateAsync(string name, INavigationParameters parameters, bool? useModalNavigation, bool animated);
+
+        Task<INavigationResult> NavigateAsync(Uri uri, INavigationParameters parameters, bool? useModalNavigation, bool animated);
+    }
+}

Source/Xamarin/Prism.Forms/Navigation/PageNavigationService.cs

@@ -13,7 +13,7 @@ namespace Prism.Navigation
     /// <summary>
     /// Provides page based navigation for ViewModels.
     /// </summary>
-    public class PageNavigationService : INavigationService, INavigateInternal, IPageAware
+    public class PageNavigationService : INavigationService, IPlatformNavigationService, IPageAware
     {
         internal const string RemovePageRelativePath = "../";
         internal const string RemovePageInstruction = "__RemovePage/";
@@ -61,6 +61,11 @@ public virtual Task<INavigationResult> GoBackAsync(INavigationParameters paramet
             return GoBackInternal(parameters, null, true);
         }
 
+        Task<INavigationResult> IPlatformNavigationService.GoBackAsync(INavigationParameters parameters, bool? useModalNavigation, bool animated)
+        {
+            return GoBackInternal(parameters, useModalNavigation, animated);
+        }
+
         /// <summary>
         /// Navigates to the most recent entry in the back navigation history by popping the calling Page off the navigation stack.
         /// </summary>
@@ -118,6 +123,11 @@ protected async virtual Task<INavigationResult> GoBackInternal(INavigationParame
             return result;
         }
 
+        Task<INavigationResult> IPlatformNavigationService.GoBackToRootAsync(INavigationParameters parameters)
+        {
+            return GoBackToRootInternal(parameters);
+        }
+
         /// <summary>
         /// When navigating inside a NavigationPage: Pops all but the root Page off the navigation stack
         /// </summary>
@@ -174,16 +184,6 @@ protected async virtual Task<INavigationResult> GoBackToRootInternal(INavigation
             }
         }
 
-        Task<INavigationResult> INavigateInternal.GoBackInternal(INavigationParameters parameters, bool? useModalNavigation, bool animated)
-        {
-            return GoBackInternal(parameters, useModalNavigation, animated);
-        }
-
-        Task<INavigationResult> INavigateInternal.GoBackToRootInternal(INavigationParameters parameters)
-        {
-            return GoBackToRootInternal(parameters);
-        }
-
         /// <summary>
         /// Initiates navigation to the target specified by the <paramref name="name"/>.
         /// </summary>
@@ -203,6 +203,11 @@ public virtual Task<INavigationResult> NavigateAsync(string name, INavigationPar
             return NavigateInternal(name, parameters, null, true);
         }
 
+        Task<INavigationResult> IPlatformNavigationService.NavigateAsync(string name, INavigationParameters parameters, bool? useModalNavigation, bool animated)
+        {
+            return NavigateInternal(name, parameters, useModalNavigation, animated);
+        }
+
         /// <summary>
         /// Initiates navigation to the target specified by the <paramref name="name"/>.
         /// </summary>
@@ -218,11 +223,6 @@ protected virtual Task<INavigationResult> NavigateInternal(string name, INavigat
             return NavigateInternal(UriParsingHelper.Parse(name), parameters, useModalNavigation, animated);
         }
 
-        Task<INavigationResult> INavigateInternal.NavigateInternal(string name, INavigationParameters parameters, bool? useModalNavigation, bool animated)
-        {
-            return NavigateInternal(name, parameters, useModalNavigation, animated);
-        }
-
         /// <summary>
         /// Initiates navigation to the target specified by the <paramref name="uri"/>.
         /// </summary>
@@ -250,6 +250,11 @@ public virtual Task<INavigationResult> NavigateAsync(Uri uri, INavigationParamet
             return NavigateInternal(uri, parameters, null, true);
         }
 
+        Task<INavigationResult> IPlatformNavigationService.NavigateAsync(Uri uri, INavigationParameters parameters, bool? useModalNavigation, bool animated)
+        {
+            return NavigateInternal(uri, parameters, useModalNavigation, animated);
+        }
+
         /// <summary>
         /// Initiates navigation to the target specified by the <paramref name="uri"/>.
         /// </summary>
@@ -296,11 +301,6 @@ protected async virtual Task<INavigationResult> NavigateInternal(Uri uri, INavig
             }
         }
 
-        Task<INavigationResult> INavigateInternal.NavigateInternal(Uri uri, INavigationParameters parameters, bool? useModalNavigation, bool animated)
-        {
-            return NavigateInternal(uri, parameters, useModalNavigation, animated);
-        }
-
         protected virtual async Task ProcessNavigation(Page currentPage, Queue<string> segments, INavigationParameters parameters, bool? useModalNavigation, bool animated)
         {
             if (segments.Count == 0)