fix: Fix UWP activating too soon (#1930)

src/ReactiveUI/Platforms/windows-common/ActivationForViewFetcher.cs → src/ReactiveUI.Wpf/ActivationForViewFetcher.cs

@@ -9,10 +9,6 @@
 using System.Reflection;
 using System.Windows;
 
-#if NETFX_CORE
-using Windows.UI.Xaml;
-#endif
-
 namespace ReactiveUI
 {
     /// <summary>
@@ -37,14 +33,7 @@ public IObservable<bool> GetActivationForView(IActivatable view)
             {
                 return Observable<bool>.Empty;
             }
-#if WINDOWS_UWP
-            var viewLoaded = WindowsObservable.FromEventPattern<FrameworkElement, object>(
-                x => fe.Loading += x,
-                x => fe.Loading -= x)
-                .Select(_ => true);
 
-            var hitTestVisible = fe.WhenAnyValue(x => x.IsHitTestVisible);
-#else
             var viewLoaded = Observable.FromEventPattern<RoutedEventHandler, RoutedEventArgs>(
                 x => fe.Loaded += x,
                 x => fe.Loaded -= x)
@@ -54,7 +43,6 @@ public IObservable<bool> GetActivationForView(IActivatable view)
                 x => fe.IsHitTestVisibleChanged += x,
                 x => fe.IsHitTestVisibleChanged -= x)
                 .Select(x => (bool)x.EventArgs.NewValue);
-#endif
 
             var viewUnloaded = Observable.FromEventPattern<RoutedEventHandler, RoutedEventArgs>(
                 x => fe.Unloaded += x,

src/ReactiveUI/Platforms/uap10.0.16299/ActivationForViewFetcher.cs

@@ -0,0 +1,54 @@
+// Copyright (c) 2019 .NET Foundation and Contributors. All rights reserved.
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+using System;
+using System.Linq;
+using System.Reactive.Linq;
+using System.Reflection;
+using System.Windows;
+
+using Windows.UI.Xaml;
+
+namespace ReactiveUI
+{
+    /// <summary>
+    /// ActiveationForViewFetcher is how ReactiveUI determine when a
+    /// View is activated or deactivated. This is usually only used when porting
+    /// ReactiveUI to a new UI framework.
+    /// </summary>
+    public class ActivationForViewFetcher : IActivationForViewFetcher
+    {
+        /// <inheritdoc/>
+        public int GetAffinityForView(Type view)
+        {
+            return typeof(FrameworkElement).GetTypeInfo().IsAssignableFrom(view.GetTypeInfo()) ? 10 : 0;
+        }
+
+        /// <inheritdoc/>
+        public IObservable<bool> GetActivationForView(IActivatable view)
+        {
+            var fe = view as FrameworkElement;
+
+            if (fe == null)
+            {
+                return Observable<bool>.Empty;
+            }
+
+            var viewLoaded = WindowsObservable.FromEventPattern<FrameworkElement, object>(
+                x => fe.Loading += x,
+                x => fe.Loading -= x).Select(_ => true);
+
+            var viewUnloaded = Observable.FromEventPattern<RoutedEventHandler, RoutedEventArgs>(
+                x => fe.Unloaded += x,
+                x => fe.Unloaded -= x).Select(_ => false);
+
+            return viewLoaded
+                .Merge(viewUnloaded)
+                .Select(b => b ? fe.WhenAnyValue(x => x.IsHitTestVisible).SkipWhile(x => !x) : Observables.False)
+                .Switch()
+                .DistinctUntilChanged();
+        }
+    }
+}