MultilineEntryElement for Monotouch.Dialog

gistfile1.cs

using System;
using CrossUI.Touch.Dialog.Elements;
using System.Drawing;
using MonoTouch.UIKit;
using MonoTouch.Foundation;
using CrossUI.Touch.Dialog;

/// <summary>
/// Multiline entry element.
/// </summary>
public class MultilineEntryElement : EntryElement, IElementSizing
{
  private bool _becomeResponder;
	private readonly string _placeholder;

	/// <summary>
	/// Constructs an MultilineEntryElement with the given placeholder.
	/// </summary>
	/// <param name="placeholder">
	/// Placeholder to display when no value is set.
	/// </param>
	public MultilineEntryElement(string placeholder)
		:base()
	{
		this._placeholder = placeholder;
	}

	public event EventHandler Changed;
	/// <summary>
	/// LostFocus essentially
	/// </summary>
	public event EventHandler Ended;
	
	public override string Summary()
	{
		return Value;
	}
	
	private static readonly NSString cellkey = new NSString("MultilineEntryElement");
	
	protected override NSString CellKey
	{
		get { return cellkey; }
	}
	
	protected override UITableViewCell GetCellImpl(UITableView tv)
	{
		var cell = tv.DequeueReusableCell(CellKey) as MultilineEntryCell;
		if (cell == null)
		{
			cell = new MultilineEntryCell(CellKey);
			cell.SelectionStyle = UITableViewCellSelectionStyle.None;

			cell.Entry.Changed += delegate { FetchAndUpdateValue(); };

			cell.Entry.Ended += delegate {
				FetchAndUpdateValue();

				var f = Ended;
				if (f != null)
					f(this, null);
			};
		}

		cell.Update("_placeholder", Value);

		if (_becomeResponder)
		{
			cell.BecomeFirstResponder();
			_becomeResponder = false;
		}

		return cell;
	}

	protected override void UpdateDetailDisplay(UITableViewCell cell)
	{
		if (cell != null)
			((MultilineEntryCell)cell).Update(_placeholder, Value);
	}
	
	/// <summary>
	///  Copies the value from the UITextField in the EntryElement to the
	//   Value property and raises the Changed event if necessary.
	/// </summary>
	public void FetchAndUpdateValue()
	{
		var cell = (MultilineEntryCell)this.GetActiveCell();

		if (cell == null)
			return;
		
		var newValue = cell.Entry.Text;
		if (newValue == Value)
			return;
		
		OnUserValueChanged(newValue);

		if (Changed != null)
			Changed(this, EventArgs.Empty);
	}
	
	public override void Selected(DialogViewController dvc, UITableView tableView, NSIndexPath indexPath)
	{
		BecomeFirstResponder(true);
		tableView.DeselectRow(indexPath, true);
	}
	
	public override bool Matches(string text)
	{
		return (Value != null ? Value.IndexOf(text, StringComparison.CurrentCultureIgnoreCase) != -1 : false) ||
			base.Matches(text);
	}
	
	/// <summary>
	/// Makes this cell the first responder (get the focus)
	/// </summary>
	/// <param name="animated">
	/// Whether scrolling to the location of this cell should be animated
	/// </param>
	public override void BecomeFirstResponder(bool animated)
	{
		_becomeResponder = true;

		var tv = GetContainerTableView();
		if (tv == null)
			return;
		tv.ScrollToRow(IndexPath, UITableViewScrollPosition.Middle, animated);

		//After scrolling, become first responder. If you try do this before the scroll doesn't work.
		tv.ScrollAnimationEnded += BecomeFirstResponderDelayed;
	}

	private void BecomeFirstResponderDelayed(object sender, EventArgs args)
	{
		var cell = (MultilineEntryCell)this.GetActiveCell();
		if (cell != null)
		{
			cell.BecomeFirstResponder();
			_becomeResponder = false;
		}

		GetContainerTableView().ScrollAnimationEnded -= BecomeFirstResponderDelayed;
	}
	
	public void ResignFirstResponder(bool animated)
	{
		_becomeResponder = false;

		var tv = GetContainerTableView();
		if (tv == null)
			return;
		tv.ScrollToRow(IndexPath, UITableViewScrollPosition.Middle, animated);

		var cell = (MultilineEntryCell)this.GetActiveCell();
		if (cell != null)
			cell.ResignFirstResponder();
	}

	public bool IsFirstResponder
	{
		get
		{
			var cell = (MultilineEntryCell)this.GetActiveCell();
			return cell != null ? cell.IsFirstResponder : false;
		}
	}
	
	public virtual float GetHeight(UITableView tableView, NSIndexPath indexPath)
	{
		return 114f;
	}

	/// <summary>
	/// Cell used to store the Multiline Entry and Placeholder.
	/// </summary>
	private class MultilineEntryCell : UITableViewCell
	{
		public const float Height = 114f;
		
		public static UIFont Font = UIFont.SystemFontOfSize (15);
		
		private UIView _view;
		private UILabel _placeholderLabel;
		private string _placeholder = null;
		
		public MultilineEntryCell(NSString key)
			: base (UITableViewCellStyle.Default, key)
		{
			_view = new UIView(new RectangleF (0, 0, 1, 1));
			
			_placeholderLabel = new UILabel(new RectangleF(8f, 1f, 290f, 37f))
			{
				TextColor = UIColor.LightGray,
				Font = Font,
				BackgroundColor = UIColor.Clear
			};
			_view.AddSubview(_placeholderLabel);
			
			Entry = new UITextView(new RectangleF(0f, 2f, 290f, 108f))
			{
				AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleLeftMargin,
				Font = Font,
				BackgroundColor = UIColor.Clear,
				TextColor = UIColor.FromRGB(25, 75, 127)
			};

			Entry.Changed += delegate {
				if(Entry.Text.Length == 0)
					_placeholderLabel.Text = _placeholder;
				else
					_placeholderLabel.Text = "";
			};
			
			_view.AddSubview(Entry);
			
			ContentView.AddSubview(_view);
		}

		public UITextView Entry { get; private set; }
		
		public override void LayoutSubviews()
		{
			base.LayoutSubviews();
			
			Entry.Frame = new RectangleF(0f, 2f, 290f, 108f);
			_view.Frame = new RectangleF(new PointF(3f, 0), ContentView.Frame.Size);
			_view.SetNeedsLayout();
		}
		
		public void Update(string placeholder, string value)
		{
			_placeholder = placeholder;
			_placeholderLabel.Text = string.IsNullOrEmpty(value) ? placeholder : "";
			Entry.Text = value;
			SetNeedsDisplay();
		}

		public override bool BecomeFirstResponder()
		{
			return Entry.BecomeFirstResponder();
		}
		
		public override bool ResignFirstResponder()
		{
			return Entry.ResignFirstResponder();
		}
		
		public bool IsFirstResponder
		{
			get
			{
				return Entry.IsFirstResponder;
			}
		}
	}
}