support configuration changes

samples/ControlCatalog.Android/ControlCatalog.Android.csproj

@@ -21,9 +21,23 @@
 
   <PropertyGroup Condition="'$(Configuration)'=='Release' and '$(TF_BUILD)' == ''">
     <DebugSymbols>True</DebugSymbols>
-    <RunAOTCompilation>True</RunAOTCompilation>
+    <RunAOTCompilation>False</RunAOTCompilation>
     <EnableLLVM>True</EnableLLVM>
   </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
+    <EmbedAssembliesIntoApk>False</EmbedAssembliesIntoApk>
+    <RunAOTCompilation>False</RunAOTCompilation>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
+    <EmbedAssembliesIntoApk>True</EmbedAssembliesIntoApk>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Xamarin.AndroidX.AppCompat" Version="1.3.1.3" />
+    <PackageReference Include="Xamarin.AndroidX.Lifecycle.ViewModel" Version="2.3.1.3" />
+  </ItemGroup>
   
   <ItemGroup>
     <ProjectReference Include="..\..\src\Android\Avalonia.Android\Avalonia.Android.csproj" />

samples/ControlCatalog.Android/MainActivity.cs

@@ -5,7 +5,7 @@ using Avalonia.Android;
 
 namespace ControlCatalog.Android
 {
-    [Activity(Label = "ControlCatalog.Android", Theme = "@style/MyTheme.NoActionBar", Icon = "@drawable/icon", LaunchMode = LaunchMode.SingleInstance)]
+    [Activity(Label = "ControlCatalog.Android", Theme = "@style/MyTheme.NoActionBar", Icon = "@drawable/icon", LaunchMode = LaunchMode.SingleInstance, ConfigurationChanges = ConfigChanges.Orientation | ConfigChanges.ScreenSize)]
     public class MainActivity : AvaloniaActivity
     {
         protected override void OnCreate(Bundle? savedInstanceState)
@@ -16,4 +16,3 @@ namespace ControlCatalog.Android
         }
     }
 }
-

samples/ControlCatalog.Android/Resources/values/styles.xml

@@ -4,7 +4,7 @@
   <style name="MyTheme">
   </style>
 
-  <style name="MyTheme.NoActionBar">
+  <style name="MyTheme.NoActionBar" parent="@style/Theme.AppCompat.NoActionBar">
     <item name="android:windowActionBar">false</item>
     <item name="android:windowNoTitle">true</item>
   </style>

src/Android/Avalonia.Android/Avalonia.Android.csproj

@@ -7,6 +7,15 @@
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\..\packages\Avalonia\Avalonia.csproj" />
+    <PackageReference Include="Xamarin.AndroidX.AppCompat" Version="1.3.1.3" />
+    <PackageReference Include="Xamarin.AndroidX.Lifecycle.ViewModel" Version="2.3.1.3" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\Avalonia.Base\Avalonia.Base.csproj" />
     <ProjectReference Include="..\..\Skia\Avalonia.Skia\Avalonia.Skia.csproj" />
   </ItemGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
+    <EmbedAssembliesIntoApk>False</EmbedAssembliesIntoApk>
+    <RunAOTCompilation>False</RunAOTCompilation>
+  </PropertyGroup>
 </Project>

src/Android/Avalonia.Android/AvaloniaActivity.cs

@@ -1,35 +1,55 @@
 using Android.App;
 using Android.OS;
 using Android.Views;
+using Android.Content.PM;
+using AndroidX.AppCompat.App;
+using Android.Content.Res;
+using AndroidX.Lifecycle;
 
 namespace Avalonia.Android
 {
-    public abstract class AvaloniaActivity : Activity
+    public abstract class AvaloniaActivity : AppCompatActivity
     {
         internal AvaloniaView View;
-        object _content;
-
+        internal AvaloniaViewModel _viewModel;
         protected override void OnCreate(Bundle savedInstanceState)
         {
             View = new AvaloniaView(this);
-            if (_content != null)
-                View.Content = _content;
             SetContentView(View);
+
+            _viewModel = new ViewModelProvider(this).Get(Java.Lang.Class.FromType(typeof(AvaloniaViewModel))) as AvaloniaViewModel;
+
+            if (_viewModel.Content != null)
+            {
+                View.Content = _viewModel.Content;
+            }
+
             base.OnCreate(savedInstanceState);
         }
-
         public object Content
         {
             get
             {
-                return _content;
+                return _viewModel.Content;
             }
             set
             {
-                _content = value;
+                _viewModel.Content = value;
                 if (View != null)
                     View.Content = value;
             }
         }
+
+        public override void OnConfigurationChanged(Configuration newConfig)
+        {
+            base.OnConfigurationChanged(newConfig);
+        }
+
+        protected override void OnDestroy()
+        {
+            View.Content = null;
+
+            base.OnDestroy();
+        }
     }
 }

src/Android/Avalonia.Android/AvaloniaViewModel.cs

@@ -0,0 +1,11 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Avalonia.Android
+{
+    internal class AvaloniaViewModel : AndroidX.Lifecycle.ViewModel
+    {
+        public object Content { get; set; }
+    }
+}