Foundations of a skinnable app

SkinnableApp.txt

// SkinnableApp/App.xaml

<?xml version="1.0" encoding="UTF-8"?>
<Application xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="SkinnableApp.App">
	<Application.Resources>
		<ResourceDictionary>
		</ResourceDictionary>
	</Application.Resources>
</Application>

// SkinnableApp/App.xaml.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Reflection;
using System.Threading.Tasks;
using Newtonsoft.Json;
using Xamarin.Forms;

namespace SkinnableApp
{
	public partial class App : Application
	{
		public App (string bundleId)
		{
			SetupIOC ();
			SetupStyles ();

			MainPage = new StartPage();
    }

		void SetupIOC ()
		{
			IOC.Container.Register<IStyleService, StyleService> ();
		}

		void SetupStyles ()
		{
			if (Resources == null) {
				Resources = new ResourceDictionary ();
			}

			IStyleService styles = IOC.Container.Resolve<IStyleService> ();
			var service = JsonConvert.DeserializeObject<StyleService> (AppState.StylesJson);
			styles.Setup (service);

			var output = JsonConvert.SerializeObject (styles);
			Debug.WriteLine (output);

			var methods = typeof(IStyleService)
				.GetRuntimeMethods ()
				.Where (m => !m.Name.StartsWith ("get_")) // remove auto-properties
				.Where (m => !m.Name.StartsWith ("set_")) // remove auto-properties
				.Where (m => !m.Name.StartsWith ("Setup")) // remove auto-properties
				.ToList ();
			foreach (var method in methods) {
				Resources.Add (method.Name, method.Invoke (styles, null));
			}
			
			var properties = typeof(IStyleService)
				.GetRuntimeProperties ();
			foreach (var property in properties) {
				Resources.Add (property.Name, property.GetValue (styles, null));
			}
		}
	}
}

// SkinnableApp.iOS/AppDelegate.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using Foundation;
using UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

namespace SkinnableApp.iOS
{
	[Register ("AppDelegate")]
	public partial class AppDelegate : FormsApplicationDelegate
	{
		public override bool FinishedLaunching (UIApplication app, NSDictionary options)
		{
			global::Xamarin.Forms.Forms.Init ();

			var formsApp = AppStarter.Start (app, options, this);
			LoadApplication (formsApp);

			return base.FinishedLaunching (app, options);
		}
	}
}

// SkinnableAppLib.iOS/AppStarter.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Runtime.CompilerServices;
using Foundation;
using UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

namespace SkinnableApp.iOS
{
	public static class AppStarter
	{
		public static Application Start (UIApplication app, 
			NSDictionary options, FormsApplicationDelegate appDelegate)
		{
			LoadConfiguration ();

			var bundleId = NSBundle.MainBundle.BundleIdentifier;

			var formsApp = new App (bundleId);

			return formsApp;
		}

		public static void LoadConfiguration ()
		{
			AppState.ResourcesJson = ReadStringAsset ("Configuration/Resources.json");
			AppState.StylesJson = ReadStringAsset ("Configuration/Styles.json");
			AppState.MenusJson = ReadStringAsset ("Configuration/Menus.json");
		}

		public static string ReadStringAsset (string path)
		{
			string assetText = File.ReadAllText (path);
			return assetText;
		}
	}
}

// SkinnableApp.Droid/MainActivity.cs

using System;
using Android.App;
using Android.Content;
using Android.Content.PM;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;

namespace SkinnableApp.Droid
{
	[Activity (Label = "SkinnableApp.Droid", 
				Icon = "@drawable/icon", 
				MainLauncher = false, 
				ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation,
				ScreenOrientation = ScreenOrientation.Portrait,
				Theme = "@style/MainTheme")]
	public class MainActivity : FormsApplicationActivity
	{
		protected override void OnCreate (Bundle bundle)
		{
			base.OnCreate (bundle);
			global::Xamarin.Forms.Forms.Init (this, bundle);

			var formsApp = AppStarter.Start (this, bundle, Forms.Context);
			LoadApplication (formsApp);
		}
	}
}

// SkinnableAppLib.Droid/AppStarter.cs

using System;
using System.IO;
using System.Linq;
using Android.App;
using Android.Content;
using Android.Content.Res;
using Android.OS;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;

namespace SkinnableApp.Droid
{
	public static class AppStarter
	{
		public static Xamarin.Forms.Application Start (FormsApplicationActivity activity, Bundle bundle, Context context)
		{
			LoadConfiguration (context);

			var bundleId = context.PackageName;

			var formsApp = new App (bundleId);

			return formsApp;
		}

		public static void LoadConfiguration (Context context)
		{
			AppState.ResourcesJson = ReadStringAsset (context, "Resources.json");
			AppState.StylesJson = ReadStringAsset (context, "Styles.json");
			AppState.MenusJson = ReadStringAsset (context, "Menus.json");
		}

		public static string ReadStringAsset (Context context, string path)
		{
			var asset = ((Activity)context).Assets.Open (path);
			string assetText;
			using (var sr = new StreamReader (asset))
			{
				assetText = sr.ReadToEnd ();
			}
			return assetText;
		}
	}
}

// Set Configuration folder as Git Subtree in project folder

// skinnableupdateios.sh

#!/bin/sh

function help () {
	echo "skinnableupdateios - simple script to keep assets in sync with designer resources"
	echo ""
	echo "  skinnableupdateios {projectdir} {resourcedir}        - {resourcedir} is resource directory in {projectdir}"
}

function dosync () {
	cd $1
	rsync -avh "../Configuration/$2/Configuration" "$1/Resources/"
	rsync -avh "../Configuration/$2/Fonts" "$1/Resources/"
	rsync -avh "../Configuration/$2/Resources/iOS/" "$1/Resources/"
}

if [ $1 ] ; then
    dosync $1 $2
else
    help
fi

// skinnableupdatedroid.sh

#!/bin/sh

function help () {
	echo "skinnableupdatedroid - simple script to keep assets in sync with designer resources"
	echo ""
	echo "  skinnableupdatedroid {projectdir} {resourcedir}        - {resourcedir} is resource directory in {projectdir}"
}

function dosync () {
	cd $1
	rsync -avh "../Configuration/$2/Configuration/" "./Assets/"
	rsync -avh "../Configuration/$2/Fonts/" "./Assets/"
	rsync -avh "../Configuration/$2/Resources/Droid/" "./Resources/"
}

if [ $1 ] ; then
    dosync $1 $2
else
    help
fi