Xamarin.Android translation of DroidParts ClearableEditText

ClearableEditText.cs

	// DroidParts is under Apache License 2.0
	// https://github.com/droidparts/droidparts/blob/master/droidparts-misc/src/org/droidparts/widget/ClearableEditText.java
	public class ClearableEditText : EditText, View.IOnTouchListener, View.IOnFocusChangeListener, ITextWatcher
	{
		public ClearableEditText(IntPtr javaReference, Android.Runtime.JniHandleOwnership transfer) : base(javaReference, transfer) { Initialize(); }
		public ClearableEditText(Context context) : base(context) { Initialize(); }
		public ClearableEditText(Context context, Android.Util.IAttributeSet attrs) : base(context, attrs) { Initialize(); }
		public ClearableEditText(Context context, Android.Util.IAttributeSet attrs, int defStyleAttr) : base(context, attrs, defStyleAttr) { Initialize(); }
		public ClearableEditText(Context context, Android.Util.IAttributeSet attrs, int defStyleAttr, int defStyleRes) : base(context, attrs, defStyleAttr, defStyleRes) { Initialize(); }

		public interface IListener
		{
			void DidClearText();
		}

		public enum Location
		{
			LEFT = 0,
			RIGHT = 2,
		}

		IListener listener;
		Location? loc = Location.RIGHT;
		Drawable xD;
		IOnTouchListener l;
		IOnFocusChangeListener f;

		public void SetListener(IListener listener)
		{
			this.listener = listener;
		}

		public void SetIconLocation(Location loc)
		{
			this.loc = loc;
			InitIcon();
		}

		void Initialize()
		{
			base.SetOnTouchListener(this);
			base.OnFocusChangeListener = this;
			InitIcon();
			SetClearIconVisible(false);
		}

		public override void SetOnTouchListener(IOnTouchListener l)
		{
			this.l = l;
		}

		public void SetOnFocusChangeListener(IOnFocusChangeListener f)
		{
			this.f = f;
		}

		void InitIcon()
		{
			xD = null;
			if (loc != null)
			{
				xD = GetCompoundDrawables()[(int)loc];
			}
			if (xD == null)
			{
				xD = Resources.GetDrawable(Android.Resource.Drawable.PresenceOffline);
			}
			xD.SetBounds(0, 0, xD.IntrinsicWidth, xD.IntrinsicHeight);
			int min = PaddingTop + xD.IntrinsicHeight + PaddingBottom;
			if (SuggestedMinimumHeight < min)
			{
				SetMinimumHeight(min);
			}
		}

		Drawable GetDisplayedDrawable()
		{
			return (loc != null) ? GetCompoundDrawables()[(int)loc] : null;
		}

		void SetClearIconVisible(bool visible)
		{
			Drawable[] cd = GetCompoundDrawables();
			Drawable displayed = GetDisplayedDrawable();
			var wasVisible = (displayed != null);
			if (visible != wasVisible)
			{
				Drawable x = visible ? xD : null;
				base.SetCompoundDrawables((loc == Location.LEFT) ? x : cd[0], cd[1], (loc == Location.RIGHT) ? x : cd[2], cd[3]);
			}
		}

		public bool OnTouch(View v, MotionEvent e)
		{
			if (GetDisplayedDrawable() != null)
			{
				int x = (int)e.GetX();
				int y = (int)e.GetY();
				int left = (loc == Location.LEFT) ? 0 : Width - PaddingRight - xD.IntrinsicWidth;
				int right = (loc == Location.LEFT) ? PaddingLeft + xD.IntrinsicWidth : Width;
				bool tappedX = x >= left && x <= right && y >= 0 && y <= (Bottom - Top);
				if (tappedX)
				{
					if (e.Action == MotionEventActions.Up)
					{
						Text = "";
						if (listener != null)
						{
							listener.DidClearText();
						}
					}
					return true;
				}
			}
			if (l != null)
				return l.OnTouch(v, e);
			return false;
		}

		public void OnFocusChange(View v, bool hasFocus)
		{
			if (hasFocus)
				SetClearIconVisible(!string.IsNullOrEmpty(Text));
			else
				SetClearIconVisible(false);
			if (f != null)
				f.OnFocusChange(v, hasFocus);
		}

		void ITextWatcher.OnTextChanged(ICharSequence s, int start, int before, int count)
		{
			if (IsFocused)
				SetClearIconVisible(!string.IsNullOrEmpty(Text));
		}

		void ITextWatcher.AfterTextChanged(IEditable s)
		{
		}

		void ITextWatcher.BeforeTextChanged(ICharSequence s, int start, int count, int after)
		{
		}
	}

AXML Example:

    <sushihangover.ClearableEditText
        android:id="@+id/clearableEditText1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="StackOverflow Right Clear"
        />

Left Clear Button Example:

var clearable2 = FindViewById<ClearableEditText>(Resource.Id.clearableEditText2);
clearable2.SetIconLocation(ClearableEditText.Location.LEFT);