Fix Resource Manager code to use native APIs before reflection

Xamarin.Forms.ControlGallery.Android/CustomRenderers.cs

@@ -115,7 +115,7 @@ protected override void UpdateMenuItemIcon(Context context, IMenuItem menuItem,
 				if (toolBarItem.IconImageSource is FileImageSource fileImageSource)
 				{
 					var name = IOPath.GetFileNameWithoutExtension(fileImageSource.File);
-					var id = Xamarin.Forms.Platform.Android.ResourceManager.GetDrawableByName(name);
+					var id = context.GetDrawableId(name);
 					if (id != 0)
 					{
 						if ((int)Build.VERSION.SdkInt >= 21)

Xamarin.Forms.ControlGallery.Android/FormsAppCompatActivity.cs

@@ -51,6 +51,12 @@ protected override void OnCreate(Bundle bundle)
 #endif
 			Forms.Init(this, bundle);
 
+			// null out the assembly on the Resource Manager
+			// so all of our tests run without using the reflection APIs
+			// At some point the Resources class types will go away so
+			// reflection will stop working
+			ResourceManager.Init(null);
+
 			FormsMaps.Init(this, bundle);
 			FormsMaterial.Init(this, bundle);
 			AndroidAppLinks.Init(this);

Xamarin.Forms.Platform.Android.UnitTests/ButtonTests.cs

@@ -12,6 +12,7 @@
 using Xamarin.Forms;
 using Xamarin.Forms.CustomAttributes;
 using AColor = Android.Graphics.Color;
+using AContextThemeWrapper = Android.Support.V7.View.ContextThemeWrapper;
 
 namespace Xamarin.Forms.Platform.Android.UnitTests
 {
@@ -95,25 +96,26 @@ public void StyleTextAllCapsSettingIsRespected()
 		}
 
 		// This is the ideal test for Issue11703. It's currently being tabled due to a Resource linking bug that we're working out with Android team
-		//[Category("Button")]
-		//[Description("Account for user's setting of styles property textAllCaps")]
-		//[Issue(IssueTracker.Github, 11703, "[Bug] Android textAllCaps no longer works", issueTestNumber: 1)]
-		//[TestCase(false)]
-		//[TestCase(true)]
-		//public void StyleTextAllCapsSettingIsRespected(bool allCaps)
-		//{
-		//	ContextThemeWrapper contextThemeWrapper = null;
-		//	if (allCaps)
-		//		contextThemeWrapper = new ContextThemeWrapper(Context, Resource.Style.TextAllCapsStyleTrue);
-		//	else
-		//		contextThemeWrapper = new ContextThemeWrapper(Context, Resource.Style.TextAllCapsStyleFalse);
+		/*[Category("Button")]
+		[Description("Account for user's setting of styles property textAllCaps")]
+		[Issue(IssueTracker.Github, 11703, "[Bug] Android textAllCaps no longer works", issueTestNumber: 1)]
+		[TestCase(false)]
+		[TestCase(true)]
+		public async Task StyleTextAllCapsSettingIsRespected(bool allCaps)
+		{
+			AContextThemeWrapper contextThemeWrapper = null;
+			if (allCaps)
+				contextThemeWrapper = new AContextThemeWrapper(Context, Context.GetStyle("TextAllCapsStyleTrue"));
+			else
+				contextThemeWrapper = new AContextThemeWrapper(Context, Context.GetStyle("TextAllCapsStyleFalse"));
 
-		//	var button = new Button { Text = "foo" };
-		//	var buttonControl = GetRenderer(button, contextThemeWrapper).View as AppCompatButton;
-		//	var initialTextTransform = buttonControl.TransformationMethod;
+			var button = new Button { Text = "foo" };
+			var initialTextTransform = await GetControlProperty(button, x => x.TransformationMethod);
 
-		//	Assert.AreEqual(allCaps, initialTextTransform is AllCapsTransformationMethod);
-		//}
+			// when set through a style the type is an internal version of AllCapsTransformationMethod
+			string typeName = $"{initialTextTransform}";
+			Assert.AreEqual(allCaps, typeName.Contains("AllCapsTransformationMethod"));
+		}*/
 
 	}
 }

Xamarin.Forms.Platform.Android.UnitTests/ResourceManagerTests.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Threading.Tasks;
+using Android.Views;
+using NUnit.Framework;
+
+namespace Xamarin.Forms.Platform.Android.UnitTests
+{
+	[TestFixture]
+	public class ResourceManagerTests : PlatformTestFixture
+	{
+		[Test, Category("Resource")]
+		[Description("Retrieve Resources by Name")]
+		public void RetrieveResourcesByName()
+		{
+			ResourceManager.Init(null);
+			ResourceManager.DrawableClass = null;
+			ResourceManager.LayoutClass = null;
+			ResourceManager.ResourceClass = null;
+			ResourceManager.StyleClass = null;
+
+			Assert.Greater(ResourceManager.GetDrawableId(this.Context, "DrawableTEST"), 0);
+			Assert.Greater(ResourceManager.GetDrawableId(this.Context, "DrawableTEST.png"), 0);
+			Assert.Greater(ResourceManager.GetLayout(this.Context, "LayoutTest"), 0);
+			Assert.Greater(ResourceManager.GetStyle(this.Context, "TextAllCapsStyleTrue"), 0);
+			Assert.Greater(ResourceManager.GetResource(this.Context, "namewith.adot"), 0);
+			Assert.Greater(ResourceManager.GetResource(this.Context, "namewith_adot"), 0);
+
+		}
+	}
+}

Xamarin.Forms.Platform.Android.UnitTests/Resources/layout/LayoutTest.axml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<android.support.design.widget.CoordinatorLayout
+		xmlns:android="http://schemas.android.com/apk/res/android"
+		xmlns:app="http://schemas.android.com/apk/res-auto"
+		android:layout_width="match_parent"
+		android:layout_height="match_parent"
+		>
+
+	<android.support.design.widget.AppBarLayout
+			android:id="@+id/namewith.adot"
+			android:layout_width="match_parent"
+			android:layout_height="wrap_content"
+			android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
+				>
+
+		<android.support.v7.widget.Toolbar
+				android:layout_width="match_parent"
+				android:layout_height="?attr/actionBarSize"
+				app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />
+
+	</android.support.design.widget.AppBarLayout>
+
+</android.support.design.widget.CoordinatorLayout>

Xamarin.Forms.Platform.Android.UnitTests/Xamarin.Forms.Platform.Android.UnitTests.csproj

@@ -70,6 +70,7 @@
     <Compile Include="ButtonTests.cs" />
     <Compile Include="BackgroundTests.cs" />
     <Compile Include="TestActivity.cs" />
+    <Compile Include="ResourceManagerTests.cs" />
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="NUnit">
@@ -97,6 +98,12 @@
   </ItemGroup>
   <ItemGroup>
     <AndroidResource Include="Resources\values\styles.xml" />
+    <AndroidResource Include="Resources\layout\LayoutTest.axml" />
+    <AndroidResource Include="Resources\drawable\DrawableTest.png" />
+  </ItemGroup>
+  <ItemGroup>
+    <Folder Include="Resources\drawable\" />
+    <Folder Include="Resources\layout\" />
   </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\Android\Xamarin.Android.CSharp.targets" />
 </Project>

Xamarin.Forms.Platform.Android/Platform.cs

@@ -803,7 +803,7 @@ void GetNewMasterDetailToggle()
 			if (fileImageSource == null)
 					throw new InvalidOperationException("Icon property must be a FileImageSource on Master page");
 
-			int icon = ResourceManager.GetDrawableByName(fileImageSource);
+			int icon = _activity.GetDrawableId(fileImageSource);
 
 			FastRenderers.AutomationPropertiesProvider.GetDrawerAccessibilityResources(_activity, CurrentMasterDetailPage, out int resourceIdOpen, out int resourceIdClose);
 #pragma warning disable 618 // Eventually we will need to determine how to handle the v7 ActionBarDrawerToggle for AppCompat

Xamarin.Forms.Platform.Android/Renderers/AndroidGIFImageParser.cs

@@ -194,7 +194,7 @@ public override bool SelectDrawable(int index)
 				InJustDecodeBounds = true
 			};
 
-			int drawableIdentifier = ResourceManager.GetDrawableByName(file);
+			int drawableIdentifier = context.GetDrawableId(file);
 
 			if (drawableIdentifier != 0)
 			{

Xamarin.Forms.Platform.Android/ResourceManager.cs

@@ -29,7 +29,7 @@ public static class ResourceManager
 		static Assembly _assembly;
 		static Type FindType(string name, string altName)
 		{
-			return _assembly.GetTypes().FirstOrDefault(x => x.Name == name || x.Name == altName);
+			return _assembly?.GetTypes().FirstOrDefault(x => x.Name == name || x.Name == altName);
 		}
 		static Type _drawableClass;
 		static Type _resourceClass;
@@ -93,7 +93,7 @@ public static Type LayoutClass {
 			if (imageSource is FileImageSource fileImageSource)
 			{
 				var file = fileImageSource.File;
-				var id = IdFromTitle(file, DrawableClass);
+				var id = IdFromTitle(file, DrawableClass, "drawable", context);
 
 				// try the drawables via id
 				if (id != 0)
@@ -353,29 +353,47 @@ public static Drawable GetDrawable(this Context context, string name)
 			return AndroidAppCompat.GetDrawable(context, id);
 		}
 
+		public static int GetDrawableId(this Context context, string title)
+		{
+			return IdFromTitle(title, DrawableClass, _drawableDefType, context);
+		}
+
+		[Obsolete("GetDrawableByName(string) is obsolete as of version 4.8. "
+			+ "Please use GetDrawableId(string, context) instead.")]
 		public static int GetDrawableByName(string name)
 		{
-			return IdFromTitle(name, DrawableClass);
+			return IdFromTitle(name, DrawableClass, _drawableDefType, Forms.ApplicationContext);
 		}
 
+		[Obsolete("GetResourceByName(string) is obsolete as of version 4.8. "
+			+ "Please use GetResource(string, context) instead.")]
 		public static int GetResourceByName(string name)
 		{
-			return IdFromTitle(name, ResourceClass);
+			return IdFromTitle(name, ResourceClass, "id", Forms.ApplicationContext);
+		}
+
+		public static int GetResource(this Context context, string title)
+		{
+			return IdFromTitle(title, ResourceClass, "id", context);
 		}
 
+		[Obsolete("GetLayoutByName(string) is obsolete as of version 4.8. "
+			+ "Please use GetLayout(string, context) instead.")]
 		public static int GetLayoutByName(string name)
 		{
-			return IdFromTitle(name, LayoutClass);
+			return IdFromTitle(name, LayoutClass, "layout", Forms.ApplicationContext);
 		}
 
 		public static int GetLayout(this Context context, string name)
 		{
 			return IdFromTitle(name, LayoutClass, "layout", context);
 		}
 
+		[Obsolete("GetStyleByName(string) is obsolete as of version 4.8. "
+			+ "Please use GetStyle(string, context) instead.")]
 		public static int GetStyleByName(string name)
 		{
-			return IdFromTitle(name, StyleClass);
+			return IdFromTitle(name, StyleClass, "style", Forms.ApplicationContext);
 		}
 
 		public static int GetStyle(this Context context, string name)
@@ -388,24 +406,14 @@ public static void Init(Assembly masterAssembly)
 			_assembly = masterAssembly;
 		}
 
-		static int IdFromTitle(string title, Type type)
-		{
-			if (title == null)
-				return 0;
-
-			string name = IOPath.GetFileNameWithoutExtension(title);
-			int id = GetId(type, name);
-			return id;
-		}
-
 		static int IdFromTitle(string title, Type resourceType, string defType, Resources resource)
 		{
 			return IdFromTitle(title, resourceType, defType, resource, AppCompat.Platform.GetPackageName());
 		}
 
 		static int IdFromTitle(string title, Type resourceType, string defType, Context context)
 		{
-			return IdFromTitle(title, resourceType, defType, context.Resources, context.PackageName);
+			return IdFromTitle(title, resourceType, defType, context?.Resources, context?.PackageName);
 		}
 
 		static int IdFromTitle(string title, Type resourceType, string defType, Resources resource, string packageName)
@@ -414,24 +422,38 @@ static int IdFromTitle(string title, Type resourceType, string defType, Resource
 			if (title == null)
 				return id;
 
-			string name = IOPath.GetFileNameWithoutExtension(title);
+			string name;
 
-			id = GetId(resourceType, name);
+			if (defType == "style" || (resourceType != null && resourceType == StyleClass))
+				name = title;
+			else
+				name = title.ToLower();
 
-			if (id > 0)
+			if (defType == _drawableDefType || (resourceType != null && resourceType == DrawableClass))
+				name = IOPath.GetFileNameWithoutExtension(name);
+
+			if ((id = SearchByIdentifier(name, defType, resource, packageName)) > 0)
 				return id;
 
-			if (packageName != null)
+			// When searching by reflection you would use a "_" instead of a "."
+			// So this accounts for cases where users were searching with an "_"
+			if ((id = SearchByIdentifier(name.Replace("_", "."), defType, resource, packageName)) > 0)
+				return id;
+
+			int SearchByIdentifier(string n, string d, Resources r, string p)
 			{
-				id = resource.GetIdentifier(name, defType, packageName);
+				int returnValue = 0;
 
-				if (id > 0)
-					return id;
-			}
+				if (p != null)
+					returnValue = r.GetIdentifier(n, d, p);
 
-			id = resource.GetIdentifier(name, defType, null);
+				if (returnValue == 0)
+					returnValue = r.GetIdentifier(n, d, null);
+
+				return returnValue;
+			}
 
-			return id;
+			return GetId(resourceType, name);
 		}
 
 		static int GetId(Type type, string memberName)