TodoList.xaml.cs

public partial class TodoList : ContentPage
{
	IEasyMobileServiceClient _client;

	public TodoList(IEasyMobileServiceClient client)
	{
		InitializeComponent();
		_client = client;
	}

	protected override async void OnAppearing()
	{
		base.OnAppearing();

		// Set syncItems to true in order to synchronize the data on startup when running in offline mode
		await RefreshItems(true, syncItems: true);
	}

	// Data methods
	async Task AddItem(TodoItem item)
	{
		await _client.Table<TodoItem>().AddAsync(item);
		todoList.ItemsSource = await _client.Table<TodoItem>().GetItemsAsync();
	}

	async Task CompleteItem(TodoItem item)
	{
		item.Done = true;
		await _client.Table<TodoItem>().UpdateAsync(item);
		todoList.ItemsSource = await _client.Table<TodoItem>().GetItemsAsync();
	}

	public async void OnAdd(object sender, EventArgs e)
	{
		var todo = new TodoItem { Name = newItemName.Text };
		await AddItem(todo);

		newItemName.Text = string.Empty;
		newItemName.Unfocus();
	}

	// Event handlers
	public async void OnSelected(object sender, SelectedItemChangedEventArgs e)
	{
		var todo = e.SelectedItem as TodoItem;
		if(Device.OS != TargetPlatform.iOS && todo != null)
		{
			// Not iOS - the swipe-to-delete is discoverable there
			if(Device.OS == TargetPlatform.Android)
			{
				await DisplayAlert(todo.Name, "Press-and-hold to complete task " + todo.Name, "Got it!");
			}
			else
			{
				// Windows, not all platforms support the Context Actions yet
				if(await DisplayAlert("Mark completed?", "Do you wish to complete " + todo.Name + "?", "Complete", "Cancel"))
				{
					await CompleteItem(todo);
				}
			}
		}

		// prevents background getting highlighted
		todoList.SelectedItem = null;
	}

	// http://developer.xamarin.com/guides/cross-platform/xamarin-forms/working-with/listview/#context
	public async void OnComplete(object sender, EventArgs e)
	{
		var mi = ((MenuItem)sender);
		var todo = mi.CommandParameter as TodoItem;
		await CompleteItem(todo);
	}

	// http://developer.xamarin.com/guides/cross-platform/xamarin-forms/working-with/listview/#pulltorefresh
	public async void OnRefresh(object sender, EventArgs e)
	{
		var list = (ListView)sender;
		Exception error = null;
		try
		{
			await RefreshItems(false, true);
		}
		catch(Exception ex)
		{
			error = ex;
		}
		finally
		{
			list.EndRefresh();
		}

		if(error != null)
		{
			await DisplayAlert("Refresh Error", "Couldn't refresh data (" + error.Message + ")", "OK");
		}
	}

	public async void OnSyncItems(object sender, EventArgs e)
	{
		await RefreshItems(true, true);
	}

	private async Task RefreshItems(bool showActivityIndicator, bool syncItems)
	{
		using(var scope = new ActivityIndicatorScope(syncIndicator, showActivityIndicator))
		{
			todoList.ItemsSource = await _client.Table<TodoItem>().GetItemsAsync();
		}
	}

	private class ActivityIndicatorScope : IDisposable
	{
		private bool showIndicator;
		private ActivityIndicator indicator;
		private Task indicatorDelay;

		public ActivityIndicatorScope(ActivityIndicator indicator, bool showIndicator)
		{
			this.indicator = indicator;
			this.showIndicator = showIndicator;

			if(showIndicator)
			{
				indicatorDelay = Task.Delay(2000);
				SetIndicatorActivity(true);
			}
			else
			{
				indicatorDelay = Task.FromResult(0);
			}
		}

		private void SetIndicatorActivity(bool isActive)
		{
			this.indicator.IsVisible = isActive;
			this.indicator.IsRunning = isActive;
		}

		public void Dispose()
		{
			if(showIndicator)
			{
				indicatorDelay.ContinueWith(t => SetIndicatorActivity(false), TaskScheduler.FromCurrentSynchronizationContext());
			}
		}
	}
}

usings.cs

using System;
using System.Threading.Tasks;
using Xamarin.Forms;
using AppServiceHelpers.Abstractions;