Localizing the MonoTouch.Dialog Reflection API

LocalizableBindingContext.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Reflection;
using System.Text;
using MonoTouch.UIKit;
using System.Drawing;
using MonoTouch.Foundation;
using MonoTouch.Dialog;

namespace MonoTouch.Dialog
{
	[AttributeUsage (AttributeTargets.Field | AttributeTargets.Property, Inherited=false)]
	public class LocalizeAttribute : Attribute {}
	
	public class LocalizableBindingContext : IDisposable {
		public RootElement Root;
		Dictionary<Element,MemberAndInstance> mappings;
			
		class MemberAndInstance {
			public MemberAndInstance (MemberInfo mi, object o)
			{
				Member = mi;
				Obj = o;
			}
			public MemberInfo Member;
			public object Obj;
		}
		
		static object GetValue (MemberInfo mi, object o)
		{
			var fi = mi as FieldInfo;
			if (fi != null)
				return fi.GetValue (o);
			var pi = mi as PropertyInfo;
			
			var getMethod = pi.GetGetMethod ();
			return getMethod.Invoke (o, new object [0]);
		}

		static void SetValue (MemberInfo mi, object o, object val)
		{
			var fi = mi as FieldInfo;
			if (fi != null){
				fi.SetValue (o, val);
				return;
			}
			var pi = mi as PropertyInfo;
			var setMethod = pi.GetSetMethod ();
			setMethod.Invoke (o, new object [] { val });
		}
			
		static string MakeCaption (string name)
		{
			var sb = new StringBuilder (name.Length);
			bool nextUp = true;
			
			foreach (char c in name){
				if (nextUp){
					sb.Append (Char.ToUpper (c));
					nextUp = false;
				} else {
					if (c == '_'){
						sb.Append (' ');
						continue;
					}
					if (Char.IsUpper (c))
						sb.Append (' ');
					sb.Append (c);
				}
			}
			return sb.ToString ();
		}

		// Returns the type for fields and properties and null for everything else
		static Type GetTypeForMember (MemberInfo mi)
		{				
			if (mi is FieldInfo)
				return ((FieldInfo) mi).FieldType;
			else if (mi is PropertyInfo)
				return ((PropertyInfo) mi).PropertyType;
			return null;
		}
		
		public LocalizableBindingContext (object callbacks, object o, string title)
		{
			if (o == null)
				throw new ArgumentNullException ("o");
			
			mappings = new Dictionary<Element,MemberAndInstance> ();
			
			Root = new RootElement (title);
			Populate (callbacks, o, Root);
		}
		
		void Populate (object callbacks, object o, RootElement root)
		{
			MemberInfo last_radio_index = null;
			var members = o.GetType ().GetMembers (BindingFlags.DeclaredOnly | BindingFlags.Public |
				BindingFlags.NonPublic | BindingFlags.Instance
			);

			Section section = null;
			
			foreach (var mi in members) {
				Type mType = GetTypeForMember (mi);

				if (mType == null)
					continue;

				string caption = null;
				string key = null; // l18n
				object [] attrs = mi.GetCustomAttributes (false);
				bool skip = false;
				bool localize = false;
				foreach (var attr in attrs) {
					if (attr is LocalizeAttribute) {
						localize = true;
						break;
					}
				}
				foreach (var attr in attrs) {
					if (attr is SkipAttribute || attr is System.Runtime.CompilerServices.CompilerGeneratedAttribute)
						skip = true;
					else if (attr is CaptionAttribute) {
						caption = ((CaptionAttribute)attr).Caption;
						if (localize)
							caption = NSBundle.MainBundle.LocalizedString (caption, caption);
					} else if (attr is SectionAttribute) {
						if (section != null)
							root.Add (section);
						var sa = attr as SectionAttribute;
						var header = sa.Caption;
						var footer = sa.Footer;
						if (localize) {
							header = NSBundle.MainBundle.LocalizedString (header, header);
							footer = NSBundle.MainBundle.LocalizedString (footer, footer);
						}
						section = new Section (header, footer);
					}
				}
				if (skip)
					continue;
				
				if (caption == null) {
					caption = MakeCaption (mi.Name);
					if (localize)
						caption = NSBundle.MainBundle.LocalizedString (caption, caption);
				}
				
				if (section == null)
					section = new Section ();
				
				Element element = null;
				if (mType == typeof(string)) {
					PasswordAttribute pa = null;
					AlignmentAttribute align = null;
					EntryAttribute ea = null;
					object html = null;
					NSAction invoke = null;
					bool multi = false;
					
					foreach (object attr in attrs) {
						if (attr is PasswordAttribute)
							pa = attr as PasswordAttribute;
						else if (attr is EntryAttribute)
							ea = attr as EntryAttribute;
						else if (attr is MultilineAttribute)
							multi = true;
						else if (attr is HtmlAttribute)
							html = attr;
						else if (attr is AlignmentAttribute)
							align = attr as AlignmentAttribute;
						
						if (attr is OnTapAttribute) {
							string mname = ((OnTapAttribute)attr).Method;
							
							if (callbacks == null) {
								throw new Exception ("Your class contains [OnTap] attributes, but you passed a null object for `context' in the constructor");
							}
							
							var method = callbacks.GetType ().GetMethod (mname);
							if (method == null)
								throw new Exception ("Did not find method " + mname);
							invoke = delegate {
								method.Invoke (method.IsStatic ? null : callbacks, new object [0]);
							};
						}
					}
					
					
					
					string value = (string)GetValue (mi, o);
					if (pa != null) {
						var placeholder = pa.Placeholder;
						if (localize)
							placeholder = NSBundle.MainBundle.LocalizedString (placeholder, placeholder);
						element = new EntryElement (caption, placeholder, value, true);
					} else if (ea != null) {
						var placeholder = ea.Placeholder;
						if (localize)
							placeholder = NSBundle.MainBundle.LocalizedString (placeholder, placeholder);
						element = new EntryElement (caption, placeholder, value) { KeyboardType = ea.KeyboardType, AutocapitalizationType = ea.AutocapitalizationType, AutocorrectionType = ea.AutocorrectionType, ClearButtonMode = ea.ClearButtonMode };
					} else if (multi)
						element = new MultilineElement (caption, value);
					else if (html != null)
						element = new HtmlElement (caption, value);
					else {
						var selement = new StringElement (caption, value);
						element = selement;
						
						if (align != null)
							selement.Alignment = align.Alignment;
					}
					
					if (invoke != null)
						((StringElement)element).Tapped += invoke;
				} else if (mType == typeof(float)) {
					var floatElement = new FloatElement (null, null, (float)GetValue (mi, o));
					floatElement.Caption = caption;
					element = floatElement;
					
					foreach (object attr in attrs) {
						if (attr is RangeAttribute) {
							var ra = attr as RangeAttribute;
							floatElement.MinValue = ra.Low;
							floatElement.MaxValue = ra.High;
							floatElement.ShowCaption = ra.ShowCaption;
						}
					}
				} else if (mType == typeof(bool)) {
					bool checkbox = false;
					foreach (object attr in attrs) {
						if (attr is CheckboxAttribute)
							checkbox = true;
					}
					
					if (checkbox)
						element = new CheckboxElement (caption, (bool)GetValue (mi, o));
					else
						element = new BooleanElement (caption, (bool)GetValue (mi, o));
				} else if (mType == typeof(DateTime)) {
					var dateTime = (DateTime)GetValue (mi, o);
					bool asDate = false, asTime = false;
					
					foreach (object attr in attrs) {
						if (attr is DateAttribute)
							asDate = true;
						else if (attr is TimeAttribute)
							asTime = true;
					}
					
					if (asDate)
						element = new DateElement (caption, dateTime);
					else if (asTime)
						element = new TimeElement (caption, dateTime);
					else
						element = new DateTimeElement (caption, dateTime);
				} else if (mType.IsEnum) {
					var csection = new Section ();
					ulong evalue = Convert.ToUInt64 (GetValue (mi, o), null);
					int idx = 0;
					int selected = 0;
					
					foreach (var fi in mType.GetFields (BindingFlags.Public | BindingFlags.Static)) {
						ulong v = Convert.ToUInt64 (GetValue (fi, null));
						
						if (v == evalue)
							selected = idx;
						
						CaptionAttribute ca = Attribute.GetCustomAttribute (fi, typeof(CaptionAttribute)) as CaptionAttribute;
						var cap = ca != null ? ca.Caption : MakeCaption (fi.Name);
						if (localize)
							NSBundle.MainBundle.LocalizedString (cap, cap);
						csection.Add (new RadioElement (cap));
						idx++;
					}
					
					element = new RootElement (caption, new RadioGroup (null, selected)) { csection };
				} else if (mType == typeof (UIImage)){
					element = new ImageElement ((UIImage) GetValue (mi, o));
				} else if (typeof (System.Collections.IEnumerable).IsAssignableFrom (mType)){
					var csection = new Section ();
					int count = 0;
					
					if (last_radio_index == null)
						throw new Exception ("IEnumerable found, but no previous int found");
					foreach (var e in (IEnumerable) GetValue (mi, o)){
						csection.Add (new RadioElement (e.ToString ()));
						count++;
					}
					int selected = (int) GetValue (last_radio_index, o);
					if (selected >= count || selected < 0)
						selected = 0;
					element = new RootElement (caption, new MemberRadioGroup (null, selected, last_radio_index)) { csection };
					last_radio_index = null;
				} else if (typeof (int) == mType){
					foreach (object attr in attrs){
						if (attr is RadioSelectionAttribute){
							last_radio_index = mi;
							break;
						}
					}
				} else {
					var nested = GetValue (mi, o);
					if (nested != null){
						var newRoot = new RootElement (caption);
						Populate (callbacks, nested, newRoot);
						element = newRoot;
					}
				}
				
				if (element == null)
					continue;
				section.Add (element);
				mappings [element] = new MemberAndInstance (mi, o);
			}
			root.Add (section);
		}
		
		class MemberRadioGroup : RadioGroup {
			public MemberInfo mi;
			
			public MemberRadioGroup (string key, int selected, MemberInfo mi) : base (key, selected)
			{
				this.mi = mi;
			}
		}
		
		public void Dispose ()
		{
			Dispose (true);
		}
		
		protected virtual void Dispose (bool disposing)
		{
			if (disposing){
				foreach (var element in mappings.Keys){
					element.Dispose ();
				}
				mappings = null;
			}
		}
		
		public void Fetch ()
		{
			foreach (var dk in mappings){
				Element element = dk.Key;
				MemberInfo mi = dk.Value.Member;
				object obj = dk.Value.Obj;
				
				if (element is DateTimeElement)
					SetValue (mi, obj, ((DateTimeElement) element).DateValue);
				else if (element is FloatElement)
					SetValue (mi, obj, ((FloatElement) element).Value);
				else if (element is BooleanElement)
					SetValue (mi, obj, ((BooleanElement) element).Value);
				else if (element is CheckboxElement)
					SetValue (mi, obj, ((CheckboxElement) element).Value);
				else if (element is EntryElement){
					var entry = (EntryElement) element;
					entry.FetchValue ();
					SetValue (mi, obj, entry.Value);
				} else if (element is ImageElement)
					SetValue (mi, obj, ((ImageElement) element).Value);
				else if (element is RootElement){\
//HACK: RootElement.group is INTERNAL
//					var re = element as RootElement;
//					if (re.group as MemberRadioGroup != null){
//						var group = re.group as MemberRadioGroup;
//						SetValue (group.mi, obj, re.RadioSelected);
//					} else if (re.group as RadioGroup != null){
//						var mType = GetTypeForMember (mi);
//						var fi = mType.GetFields (BindingFlags.Public | BindingFlags.Static) [re.RadioSelected];
//						
//						SetValue (mi, obj, fi.GetValue (null));
//					}
				}
			}
		}
	}
}