start implementing Fingerprint stuff

src/FingerprintTest/Assets/AboutAssets.txt

@@ -0,0 +1,19 @@
+Any raw assets you want to be deployed with your application can be placed in
+this directory (and child directories) and given a Build Action of "AndroidAsset".
+
+These files will be deployed with you package and will be accessible using Android's
+AssetManager, like this:
+
+public class ReadAsset : Activity
+{
+	protected override void OnCreate (Bundle bundle)
+	{
+		base.OnCreate (bundle);
+
+		InputStream input = Assets.Open ("my_asset.txt");
+	}
+}
+
+Additionally, some Android functions will automatically load asset files:
+
+Typeface tf = Typeface.CreateFromAsset (Context.Assets, "fonts/samplefont.ttf");

src/FingerprintTest/FingerprintModule.cs

@@ -0,0 +1,268 @@
+using System;
+using Android.Content;
+using Javax.Crypto;
+using Java.Security;
+using Java.Lang;
+using Android.Views.InputMethods;
+using Android.App;
+using Android.Hardware.Fingerprints;
+using Android.OS;
+using Android.Security.Keystore;
+using Android.Preferences;
+using Java.IO;
+using Java.Security.Cert;
+
+namespace keepass2android
+{
+	public class FingerprintModule
+	{
+		public Context Context { get; set; }
+
+		public FingerprintModule (Context context)
+		{
+			Context = context;
+		}
+
+		public FingerprintManager FingerprintManager 
+		{
+			get { return (FingerprintManager) Context.GetSystemService("FingerprintManager"); }
+		}
+
+		public KeyguardManager KeyguardManager 
+		{
+			get
+			{
+				return (KeyguardManager) Context.GetSystemService("keyguard");
+			}
+		}
+	
+
+		public KeyStore Keystore
+		{
+			get
+			{
+				try
+				{
+					return KeyStore.GetInstance("AndroidKeyStore");
+				}
+				catch (KeyStoreException e)
+				{
+					throw new RuntimeException("Failed to get an instance of KeyStore", e);
+				}
+			}
+		}
+
+		public KeyGenerator KeyGenerator
+		{
+			get
+			{
+				try
+				{
+					return KeyGenerator.GetInstance(KeyProperties.KeyAlgorithmAes, "AndroidKeyStore");
+				}
+				catch (NoSuchAlgorithmException e)
+				{
+					throw new RuntimeException("Failed to get an instance of KeyGenerator", e);
+				}
+				catch (NoSuchProviderException e)
+				{
+					throw new RuntimeException("Failed to get an instance of KeyGenerator", e);
+				}
+			}
+		}
+
+		public Cipher Cipher
+		{
+			get
+			{
+				try
+				{
+					return Cipher.GetInstance(KeyProperties.KeyAlgorithmAes + "/"
+					                          + KeyProperties.BlockModeCbc + "/"
+					                          + KeyProperties.EncryptionPaddingPkcs7);
+				}
+				catch (NoSuchAlgorithmException e)
+				{
+					throw new RuntimeException("Failed to get an instance of Cipher", e);
+				}
+				catch (NoSuchPaddingException e)
+				{
+					throw new RuntimeException("Failed to get an instance of Cipher", e);
+				}
+			}
+		}
+
+		public InputMethodManager InputMethodManager 
+		{
+			get { return (InputMethodManager) Context.GetSystemService(Context.InputMethodService); }
+		}
+
+		public ISharedPreferences SharedPreferences
+		{
+			get { return PreferenceManager.GetDefaultSharedPreferences(Context); }
+		}
+	}
+
+	public class FingerprintEncryptionModule: FingerprintManager.AuthenticationCallback
+	{
+		public override void OnAuthenticationError(FingerprintState errorCode, ICharSequence errString)
+		{
+			_callback.OnAuthenticationError(errorCode, errString);
+		}
+
+		public override void OnAuthenticationFailed()
+		{
+			if (!_selfCancelled)
+				_callback.OnAuthenticationFailed();
+		}
+
+		public override void OnAuthenticationHelp(FingerprintState helpCode, ICharSequence helpString)
+		{
+			_callback.OnAuthenticationHelp(helpCode, helpString);
+		}
+
+		public override void OnAuthenticationSucceeded(FingerprintManager.AuthenticationResult result)
+		{
+			_callback.OnAuthenticationSucceeded(result);
+		}
+
+		private readonly FingerprintModule _fingerprint;
+		private readonly string _keyId;
+		private Cipher _cipher;
+		private bool _selfCancelled;
+		private CancellationSignal _cancellationSignal;
+		private FingerprintManager.CryptoObject _cryptoObject;
+		private FingerprintManager.AuthenticationCallback _callback;
+
+		public FingerprintEncryptionModule(FingerprintModule fingerprint, string keyId)
+		{
+			_fingerprint = fingerprint;
+			_keyId = keyId;
+			_cipher = fingerprint.Cipher;
+			CreateKey();
+		}
+
+		/// <summary>
+		/// Creates a symmetric key in the Android Key Store which can only be used after the user 
+		/// has authenticated with fingerprint.
+		/// </summary>
+		private void CreateKey()
+		{
+			// The enrolling flow for fingerprint. This is where you ask the user to set up fingerprint
+			// for your flow. Use of keys is necessary if you need to know if the set of
+			// enrolled fingerprints has changed.
+			try
+			{
+				_fingerprint.Keystore.Load(null);
+				// Set the alias of the entry in Android KeyStore where the key will appear
+				// and the constrains (purposes) in the constructor of the Builder
+				_fingerprint.KeyGenerator.Init(new KeyGenParameterSpec.Builder(GetAlias(_keyId),
+					KeyStorePurpose.Encrypt | KeyStorePurpose.Decrypt)
+					.SetBlockModes(KeyProperties.BlockModeCbc)
+					// Require the user to authenticate with a fingerprint to authorize every use
+					// of the key
+					.SetUserAuthenticationRequired(true)
+					.SetEncryptionPaddings(KeyProperties.EncryptionPaddingPkcs7)
+					.Build());
+				_fingerprint.KeyGenerator.GenerateKey();
+			}
+			catch (NoSuchAlgorithmException e)
+			{
+				throw new RuntimeException(e);
+			}
+			catch (InvalidAlgorithmParameterException e)
+			{
+				throw new RuntimeException(e);
+			}
+			catch (CertificateException e)
+			{
+				throw new RuntimeException(e);
+			}
+			catch (IOException e)
+			{
+				throw new RuntimeException(e);
+			}
+		}
+
+		public bool InitCipher()
+		{
+			try
+			{
+				_fingerprint.Keystore.Load(null);
+				var key = _fingerprint.Keystore.GetKey(GetAlias(_keyId), null);
+				_cipher.Init(CipherMode.EncryptMode, key);
+				_cryptoObject = new FingerprintManager.CryptoObject(_cipher);
+				return true;
+			}
+			catch (KeyPermanentlyInvalidatedException)
+			{
+				return false;
+			}
+			catch (KeyStoreException e)
+			{
+				throw new RuntimeException("Failed to init Cipher", e);
+			}
+			catch (CertificateException e)
+			{
+				throw new RuntimeException("Failed to init Cipher", e);
+			}
+			catch (UnrecoverableKeyException e)
+			{
+				throw new RuntimeException("Failed to init Cipher", e);
+			}
+			catch (IOException e)
+			{
+				throw new RuntimeException("Failed to init Cipher", e);
+			}
+			catch (NoSuchAlgorithmException e)
+			{
+				throw new RuntimeException("Failed to init Cipher", e);
+			}
+			catch (InvalidKeyException e)
+			{
+				throw new RuntimeException("Failed to init Cipher", e);
+			}
+		}
+
+		private string GetAlias(string keyId)
+		{
+			return "keepass2android." + keyId;
+		}
+
+		public bool IsFingerprintAuthAvailable
+		{
+			get
+			{
+				return _fingerprint.FingerprintManager.IsHardwareDetected
+					&& _fingerprint.FingerprintManager.HasEnrolledFingerprints;
+			}
+		}
+
+		public void StartListening(FingerprintManager.AuthenticationCallback callback)
+		{
+			if (!IsFingerprintAuthAvailable)
+				return;
+
+			_cancellationSignal = new CancellationSignal();
+			_selfCancelled = false;
+			_callback = callback;
+			_fingerprint.FingerprintManager.Authenticate(_cryptoObject, _cancellationSignal, 0 /* flags */, this, null);
+			
+		}
+
+		public void StopListening()
+		{
+			if (_cancellationSignal != null)
+			{
+				_selfCancelled = true;
+				_cancellationSignal.Cancel();
+				_cancellationSignal = null;
+			}
+		}
+
+		public void Encrypt(string textToEncrypt)
+		{
+			_cipher.DoFinal(MemUtil)
+		}
+	}
+}

src/FingerprintTest/FingerprintTest.csproj

@@ -0,0 +1,95 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProductVersion>8.0.30703</ProductVersion>
+    <SchemaVersion>2.0</SchemaVersion>
+    <ProjectGuid>{52C0A0E7-D625-44BE-948E-D98BC6C82F0F}</ProjectGuid>
+    <ProjectTypeGuids>{EFBA0AD7-5A72-4C68-AF49-83D382785DCF};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
+    <OutputType>Library</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <RootNamespace>FingerprintTest</RootNamespace>
+    <AssemblyName>FingerprintTest</AssemblyName>
+    <FileAlignment>512</FileAlignment>
+    <AndroidApplication>true</AndroidApplication>
+    <AndroidResgenFile>Resources\Resource.Designer.cs</AndroidResgenFile>
+    <GenerateSerializationAssemblies>Off</GenerateSerializationAssemblies>
+    <AndroidUseLatestPlatformSdk>True</AndroidUseLatestPlatformSdk>
+    <TargetFrameworkVersion>v6.0</TargetFrameworkVersion>
+    <AndroidManifest>Properties\AndroidManifest.xml</AndroidManifest>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <AndroidUseSharedRuntime>True</AndroidUseSharedRuntime>
+    <AndroidLinkMode>None</AndroidLinkMode>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <AndroidUseSharedRuntime>False</AndroidUseSharedRuntime>
+    <AndroidLinkMode>SdkOnly</AndroidLinkMode>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="Mono.Android" />
+    <Reference Include="mscorlib" />
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Xml" />
+    <Reference Include="Xamarin.Android.Support.v4">
+      <HintPath>..\packages\Xamarin.Android.Support.v4.23.1.1.0\lib\MonoAndroid403\Xamarin.Android.Support.v4.dll</HintPath>
+    </Reference>
+    <Reference Include="Xamarin.Android.Support.v7.AppCompat">
+      <HintPath>..\packages\Xamarin.Android.Support.v7.AppCompat.23.1.1.0\lib\MonoAndroid403\Xamarin.Android.Support.v7.AppCompat.dll</HintPath>
+    </Reference>
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="FingerprintModule.cs" />
+    <Compile Include="MainActivity.cs" />
+    <Compile Include="Resources\Resource.Designer.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="GettingStarted.Xamarin" />
+    <None Include="packages.config" />
+    <None Include="Resources\AboutResources.txt" />
+    <None Include="Assets\AboutAssets.txt" />
+  </ItemGroup>
+  <ItemGroup>
+    <AndroidResource Include="Resources\layout\Main.axml" />
+  </ItemGroup>
+  <ItemGroup>
+    <AndroidResource Include="Resources\values\Strings.xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <AndroidResource Include="Resources\drawable\Icon.png" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="Properties\AndroidManifest.xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <XamarinComponentReference Include="xamandroidsupportv7appcompat">
+      <Visible>False</Visible>
+      <Version>21.0.3.0</Version>
+    </XamarinComponentReference>
+  </ItemGroup>
+  <Import Project="$(MSBuildExtensionsPath)\Xamarin\Android\Xamarin.Android.CSharp.targets" />
+  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
+     Other similar extension points exist, see Microsoft.Common.targets.
+  <Target Name="BeforeBuild">
+  </Target>
+  <Target Name="AfterBuild">
+  </Target>
+  -->
+</Project>

src/FingerprintTest/FingerprintTest.csproj.bak

@@ -0,0 +1,81 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProductVersion>8.0.30703</ProductVersion>
+    <SchemaVersion>2.0</SchemaVersion>
+    <ProjectGuid>{52C0A0E7-D625-44BE-948E-D98BC6C82F0F}</ProjectGuid>
+    <ProjectTypeGuids>{EFBA0AD7-5A72-4C68-AF49-83D382785DCF};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
+    <OutputType>Library</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <RootNamespace>FingerprintTest</RootNamespace>
+    <AssemblyName>FingerprintTest</AssemblyName>
+    <FileAlignment>512</FileAlignment>
+    <AndroidApplication>true</AndroidApplication>
+    <AndroidResgenFile>Resources\Resource.Designer.cs</AndroidResgenFile>
+    <GenerateSerializationAssemblies>Off</GenerateSerializationAssemblies>
+    <AndroidUseLatestPlatformSdk>True</AndroidUseLatestPlatformSdk>
+    <TargetFrameworkVersion>v5.0</TargetFrameworkVersion>
+    <AndroidManifest>Properties\AndroidManifest.xml</AndroidManifest>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <AndroidUseSharedRuntime>True</AndroidUseSharedRuntime>
+    <AndroidLinkMode>None</AndroidLinkMode>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <AndroidUseSharedRuntime>False</AndroidUseSharedRuntime>
+    <AndroidLinkMode>SdkOnly</AndroidLinkMode>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="Mono.Android" />
+    <Reference Include="mscorlib" />
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="MainActivity.cs" />
+    <Compile Include="Resources\Resource.Designer.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="GettingStarted.Xamarin" />
+    <None Include="Resources\AboutResources.txt" />
+    <None Include="Assets\AboutAssets.txt" />
+  </ItemGroup>
+  <ItemGroup>
+    <AndroidResource Include="Resources\layout\Main.axml" />
+  </ItemGroup>
+  <ItemGroup>
+    <AndroidResource Include="Resources\values\Strings.xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <AndroidResource Include="Resources\drawable\Icon.png" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="Properties\AndroidManifest.xml" />
+  </ItemGroup>
+  <Import Project="$(MSBuildExtensionsPath)\Xamarin\Android\Xamarin.Android.CSharp.targets" />
+  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
+     Other similar extension points exist, see Microsoft.Common.targets.
+  <Target Name="BeforeBuild">
+  </Target>
+  <Target Name="AfterBuild">
+  </Target>
+  -->
+</Project>

src/FingerprintTest/GettingStarted.Xamarin

@@ -0,0 +1,4 @@
+<GettingStarted>
+	<LocalContent>GS\Android\CS\AndroidApp\GettingStarted.html</LocalContent>
+	<EmbeddedNavigation>false</EmbeddedNavigation>
+</GettingStarted>

src/FingerprintTest/MainActivity.cs

@@ -0,0 +1,105 @@
+using System;
+using Android;
+using Android.App;
+using Android.Content;
+using Android.Content.PM;
+using Android.Hardware.Fingerprints;
+using Android.Runtime;
+using Android.Views;
+using Android.Widget;
+using Android.OS;
+using Android.Preferences;
+using Android.Support.V7.App;
+using keepass2android;
+
+namespace FingerprintTest
+{
+	[Activity(Label = "FingerprintTest", MainLauncher = true, Icon = "@drawable/icon")]
+	public class MainActivity : AppCompatActivity
+	{
+		int count = 1;
+		const int FINGERPRINT_PERMISSION_REQUEST_CODE = 0;
+
+		protected override void OnCreate(Bundle bundle)
+		{
+			base.OnCreate(bundle);
+
+			// Set our view from the "main" layout resource
+			SetContentView(Resource.Layout.Main);
+
+			// Get our button from the layout resource,
+			// and attach an event to it
+			Button button = FindViewById<Button>(Resource.Id.MyButton);
+			button.Visibility = ViewStates.Gone;
+			
+
+			RequestPermissions(new[] { Manifest.Permission.UseFingerprint }, FINGERPRINT_PERMISSION_REQUEST_CODE);
+		}
+
+		public override void OnRequestPermissionsResult(int requestCode, string[] permissions, Permission[] grantResults)
+		{
+			if (requestCode == FINGERPRINT_PERMISSION_REQUEST_CODE && grantResults[0] == Android.Content.PM.Permission.Granted)
+			{
+				Button button = FindViewById<Button>(Resource.Id.MyButton);
+				button.Visibility = ViewStates.Visible;
+				button.Enabled = true;
+				var fingerprint = new keepass2android.FingerprintModule(this);
+
+				button.Click += (sender, args) =>
+				{
+
+				};
+				if (!fingerprint.KeyguardManager.IsKeyguardSecure)
+				{
+					button.Enabled = false;
+					// Show a message that the user hasn't set up a fingerprint or lock screen.
+					Toast.MakeText(this, "Secure lock screen hasn't set up.\n"
+						+ "Go to 'Settings -> Security -> Fingerprint' to set up a fingerprint", ToastLength.Long).Show();
+					return;
+				}
+
+
+				if (!fingerprint.FingerprintManager.HasEnrolledFingerprints)
+				{
+					button.Enabled = false;
+					// This happens when no fingerprints are registered.
+					Toast.MakeText(this, "Go to 'Settings -> Security -> Fingerprint' " +
+						"and register at least one fingerprint", ToastLength.Long).Show();
+					return;
+				}
+				var fingerprintEnc = new FingerprintEncryptionModule(fingerprint, "abc");
+
+				
+					if (fingerprintEnc.InitCipher())
+					{
+						fingerprintEnc.StartListening(new EncryptionCallback(this, fingerprintEnc));
+						
+						
+					}
+					else
+					{
+						Toast.MakeText(this, "Error initiating cipher", ToastLength.Long).Show();
+					}
+				
+			}
+		}
+	}
+
+	public class EncryptionCallback : FingerprintManager.AuthenticationCallback
+	{
+		private readonly FingerprintEncryptionModule _fingerprintEnc;
+
+		public EncryptionCallback(Context context, FingerprintEncryptionModule fingerprintEnc)
+		{
+			_fingerprintEnc = fingerprintEnc;
+		}
+
+		public override void OnAuthenticationSucceeded(FingerprintManager.AuthenticationResult result)
+		{
+			_fingerprintEnc.Encrypt("abc");
+			var edit = PreferenceManager.GetDefaultSharedPreferences(Application.Context).Edit();
+			edit.PutString("encrypted", );
+		}
+	}
+}
+

src/FingerprintTest/Properties/AndroidManifest.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="FingerprintTest.FingerprintTest" android:versionCode="1" android:versionName="1.0">
+	<uses-sdk android:targetSdkVersion="15" />
+	<application android:label="FingerprintTest" android:icon="@drawable/Icon"></application>
+</manifest>

src/FingerprintTest/Properties/AssemblyInfo.cs

@@ -0,0 +1,30 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using Android.App;
+
+// General Information about an assembly is controlled through the following 
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyTitle("FingerprintTest")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("FingerprintTest")]
+[assembly: AssemblyCopyright("Copyright ©  2015")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+[assembly: ComVisible(false)]
+
+// Version information for an assembly consists of the following four values:
+//
+//      Major Version
+//      Minor Version 
+//      Build Number
+//      Revision
+//
+// You can specify all the values or you can default the Build and Revision Numbers 
+// by using the '*' as shown below:
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]

src/FingerprintTest/Resources/AboutResources.txt

@@ -0,0 +1,50 @@
+Images, layout descriptions, binary blobs and string dictionaries can be included 
+in your application as resource files.  Various Android APIs are designed to 
+operate on the resource IDs instead of dealing with images, strings or binary blobs 
+directly.
+
+For example, a sample Android app that contains a user interface layout (main.xml),
+an internationalization string table (strings.xml) and some icons (drawable-XXX/icon.png) 
+would keep its resources in the "Resources" directory of the application:
+
+Resources/
+    drawable-hdpi/
+        icon.png
+
+    drawable-ldpi/
+        icon.png
+
+    drawable-mdpi/
+        icon.png
+
+    layout/
+        main.xml
+
+    values/
+        strings.xml
+
+In order to get the build system to recognize Android resources, set the build action to
+"AndroidResource".  The native Android APIs do not operate directly with filenames, but 
+instead operate on resource IDs.  When you compile an Android application that uses resources, 
+the build system will package the resources for distribution and generate a class called
+"Resource" that contains the tokens for each one of the resources included. For example, 
+for the above Resources layout, this is what the Resource class would expose:
+
+public class Resource {
+    public class drawable {
+        public const int icon = 0x123;
+    }
+
+    public class layout {
+        public const int main = 0x456;
+    }
+
+    public class strings {
+        public const int first_string = 0xabc;
+        public const int second_string = 0xbcd;
+    }
+}
+
+You would then use R.drawable.icon to reference the drawable/icon.png file, or Resource.layout.main 
+to reference the layout/main.xml file, or Resource.strings.first_string to reference the first 
+string in the dictionary file values/strings.xml.

src/FingerprintTest/Resources/layout/Main.axml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:orientation="vertical"
+    android:layout_width="fill_parent"
+    android:layout_height="fill_parent"
+    >
+<Button  
+    android:id="@+id/MyButton"
+    android:layout_width="fill_parent" 
+    android:layout_height="wrap_content" 
+    android:text="@string/Hello"
+    />
+</LinearLayout>

src/FingerprintTest/Resources/values/Strings.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="Hello">Hello World, Click Me!</string>
+    <string name="ApplicationName">FingerprintTest</string>
+</resources>

src/FingerprintTest/packages.config

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="Xamarin.Android.Support.v4" version="23.1.1.0" targetFramework="MonoAndroid60" />
+  <package id="Xamarin.Android.Support.v7.AppCompat" version="23.1.1.0" targetFramework="MonoAndroid60" />
+</packages>