ContactPicker.cs

using System;
using MonoTouch.Dialog;
using net.blazeware.groupsms.core.Sessions;
using net.blazeware.groupsms.Controls;
using Model = net.blazeware.groupsms.core.Model;
using System.Linq;
using net.blazeware.groupsms.UI;
using MonoTouch.UIKit;
using net.blazeware.groupsms.core.Model;
using System.Collections.Generic;
using Xamarin.Contacts;
using System.Drawing;
using System.Threading.Tasks;

namespace net.blazeware.groupsms.UI
{
  public class ContactPickerDialogViewController : DialogViewController
	{
		List<Contact> _contacts = new List<Contact>();

		Model.Group _myGroup;
		public Model.Group Group {
			get {
				return _myGroup ?? (_myGroup = new Model.Group () { Members = new List<Member> () });
			}
			set {
				_myGroup = value;
			}
		}

		public ContactPickerDialogViewController () : base (null, true)
		{
			// Events
			AppSession.Instance.AddressBookAccessDenied += HandleAddressBookAccessDenied;

			// Get contacts in async task
			Task<List<Contact>> getContacts = new Task<List<Contact>> (() => {
				return AppSession.Instance.Book.Where (a => a.Phones.Any(p => p.Type == PhoneType.Mobile)).ToList ();
			});
			getContacts.ContinueWith ((a) => {
				_contacts = a.Result;
				BeginInvokeOnMainThread (() => {
					UpdateRoot ();
				});
			}, TaskScheduler.FromCurrentSynchronizationContext());
			getContacts.Start ();
		}
		
		void HandleAddressBookAccessDenied (object sender, EventArgs e)
		{
			BeginInvokeOnMainThread (() => {
				var alert = new UIAlertView ("Permission denied", "User has denied this app access to their contacts. Please enable in your setings.", null, "Close");
				alert.Clicked += HandleAlertClicked;
				alert.Show();
			});
		}

		void HandleAlertClicked (object sender, UIButtonEventArgs e)
		{
			this.DismissViewController (true, null);
		}

		public override void LoadView ()
		{
			// Enable Search
			this.EnableSearch = true;
			this.SearchPlaceholder = "Search for a Contact";
			
			// Set tableview style
			this.Style = UITableViewStyle.Plain;

			base.LoadView ();

			// Add Root
			this.Root = new RootElement("Contacts picker");

			// Set up Navigation Buttons
			this.NavigationItem.SetRightBarButtonItem (new MonoTouch.UIKit.UIBarButtonItem(MonoTouch.UIKit.UIBarButtonSystemItem.Done), false);
			this.NavigationItem.RightBarButtonItem.Clicked += HandleDoneClicked;
		}

		public override void ViewWillDisappear (bool animated)
		{
			base.ViewWillDisappear (animated);
			AppSession.Instance.AddressBookAccessDenied -= HandleAddressBookAccessDenied;
		}

		void HandleDoneClicked (object sender, EventArgs e)
		{
			this.Group.Members.Add (new Member () {
				DisplayName = "James DARBYSHIRE",
				Number = "+61435182990"
			});

			this.NavigationController.PopViewControllerAnimated (true);
		}
		
		class IndexedSource : Source
		{
			ContactPickerDialogViewController parent;
			
			public IndexedSource (ContactPickerDialogViewController parent) : base (parent)
			{
				this.parent = parent;
			}
			
			public override string[] SectionIndexTitles (UITableView tableView)
			{
				return parent.GetSectionTitles ();
			}
		}
		
		public override Source CreateSizingSource (bool unevenRows)
		{
			return new IndexedSource (this);
		}

		void UpdateRoot ()
		{
			var sections = (from sh in "ABCDEFGHIJKLMNOPQRSTUVWXYZ" select new Section ("") {
				from element in ContactElements().Where (a => a.Caption.StartsWith (sh.ToString ()))
				select element
			});
			this.Root.Add (sections);

			this.ReloadData ();
			this.TableView.SetNeedsDisplay ();
		}
		
		string [] GetSectionTitles ()
		{
			try {
				return (from section in this.Root select (section.Header.Substring (0, 1))).ToArray ();
			}
			catch (Exception ex) {
				return null;
			}
		}

		List<Element> ContactElements ()
		{
			var elements = new List<Element> ();
			
			foreach (var contact in _contacts) {
				var element = new ObjectElement<Contact> (contact);
				elements.Add (element);
			}
			return elements;
		}
	}
}