Tables and Cells in iOS

The available v3 table sources are:

Abstract classes

• MvxBaseTableViewSource
  • base functionality only
  • no ItemsSource - generally not used directly
• MvxTableViewSource.cs
  • inherits from the basetable and adds ItemsSource for data-binding
  • inheriting classes need only to implement protected abstract UITableViewCell GetOrCreateCellFor(UITableView tableView, NSIndexPath indexPath, object item);

Concrete classes

• MvxStandardTableViewSource.cs
  • inherits from MvxTableViewSource
  • provides the 'standard iPhone cell types' via UITableViewCellStyle
  • within these you can bind TitleText, DetailText, ImageUrl and (with some teasing) Accessory
• MvxSimpleTableViewSource.cs
  • inherits from MvxTableViewSource
  • provides a single cell type for all items in the collection - via string nibName in the ctor
  • within these cells you can bind what you like - see videos (later)
• MvxActionBasedTableViewSource.cs
  • provides some Func<>style hooks to allow you to implement GetOrCreateCellFor without inheriting a new class from MvxTableViewSource

---

When creating a table I generally choose:

• in demos:
  • a MvxStandardTableViewSource - because I get a list without having to create a custom cell
• in real code:
  • a MvxSimpleTableViewSource when I only need one cell type
  • a custom class inheriting from MvxTableViewSource when I need multiple cell types - e.g. see below

---

A typical TableSource with multiple cell types typically looks like:

public class PolymorphicListItemTypesView : MvxTableViewController
{
    public PolymorphicListItemTypesView()
    {
        Title = "Poly List";
    }

    public override void ViewDidLoad()
    {
        base.ViewDidLoad();

        var source = new TableSource(TableView);
        this.AddBindings(new Dictionary<object, string>
            {
                {source, "ItemsSource Animals"}
            });

        TableView.Source = source;
        TableView.ReloadData();
    }

    public class TableSource : MvxTableViewSource
    {
        private static readonly NSString KittenCellIdentifier = new NSString("KittenCell");
        private static readonly NSString DogCellIdentifier = new NSString("DogCell");

        public TableSource(UITableView tableView)
            : base(tableView)
        {
            tableView.RegisterNibForCellReuse(UINib.FromName("KittenCell", NSBundle.MainBundle),
                                              KittenCellIdentifier);
            tableView.RegisterNibForCellReuse(UINib.FromName("DogCell", NSBundle.MainBundle), DogCellIdentifier);
        }

        public override float GetHeightForRow(UITableView tableView, NSIndexPath indexPath)
        {
            return KittenCell.GetCellHeight();
        }

        protected override UITableViewCell GetOrCreateCellFor(UITableView tableView, NSIndexPath indexPath,
                                                              object item)
        {
            NSString cellIdentifier;
            if (item is Kitten)
            {
                cellIdentifier = KittenCellIdentifier;
            }
            else if (item is Dog)
            {
                cellIdentifier = DogCellIdentifier;
            }
            else
            {
                throw new ArgumentException("Unknown animal of type " + item.GetType().Name);
            }

            return (UITableViewCell) TableView.DequeueReusableCell(cellIdentifier, indexPath);
        }
    }
}

---

For examples of creating custom tables and cells:

• there's a lot of demos of table use in the N+1 series - indexed at http://mvvmcross.wordpress.com

• N=2 and N=3 are very basic

• N=6 and N=6.5 covers a book list (a good place to start)

• N=11 covers collection views

• N=12 to N=17 make a large app with a list/table from a database

• the "Working with Collections" sample has quite a lot of Table and List code - https://github.com/slodge/MvvmCross-Tutorials/tree/master/Working%20With%20Collections

• tables are used during the Evolve presentation - http://xamarin.com/evolve/2013#session-dnoeeoarfj

• there are other samples available - see https://github.com/slodge/MvvmCross-Tutorials/ (or search on GitHub for mvvmcross - others are also posting samples)