Add TextColor Property to Picker, TimePicker, DatePicker (#84)

* Add TextColor property to TimePicker
Add TextColor page to TimePicker gallery
Add TimePicker color toggling to color toggle test page
Split color toggle tests up among tabs

* Implement TimePicker.TextColor in iOS

* Implement TimePicker.TextColor for WinRT tablet

* Add IsEnabled=false tests to DefaultColorToggleTest Button and TimePicker
Consolidate ColorStates array
Fix IsEnabled changing color bug on iOS

* Implement TimePicker.TextColor for WP8

* Add TextColor property to DatePicker
Add DatePicker section to DefaultColorToggleTest
Impement DatePicker.TextColor for WP8

* Implement DatePicker.TextColor for WinRT/UWP/Windows Phone 8.1

* Implement DatePicker.TextColor for iOS

* Add TextColor to DatePicker Gallery Page

* Implement DatePicker.TextColor for Android

* Add Picker Gallery page for TextColor
Implement Picker.TextColor on Android
Consolidate TextColor management for Button, Picker, DatePicker, TimePicker
Implement

* Add untracked TextColorSwitcher
Implement Picker.TextColor in iOS

* Implement Picker.TextColor in WinRT/UWP/Windows Phone 8.1
Remove Pioker Loaded handlers in Dispose

* Implement Picker.TextColor in WP8

* Removed unused field
Update ignored warnings

* Update docs

* Use nameof() for BindableProperties

* Cleanup

* Fix custom renderer crashes for classes using TextColorSwitcher

* Correct property name references

* Fix typo and 'if' formatting

* Add missing else

4 files changed, 43 insertions, 23 deletions

diff --git a/Xamarin.Forms.Platform.Android/Renderers/ButtonRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/ButtonRenderer.cs
index 43f042b1..7247361a 100644
--- a/Xamarin.Forms.Platform.Android/Renderers/ButtonRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/ButtonRenderer.cs
@@ -13,7 +13,7 @@ namespace Xamarin.Forms.Platform.Android
 	public class ButtonRenderer : ViewRenderer<Button, AButton>, AView.IOnAttachStateChangeListener
 	{
 		ButtonDrawable _backgroundDrawable;
-		ColorStateList _buttonDefaulTextColors;
+		TextColorSwitcher _textColorSwitcher;
 		Drawable _defaultDrawable;
 		float _defaultFontSize;
 		Typeface _defaultTypeface;
@@ -78,7 +78,7 @@ namespace Xamarin.Forms.Platform.Android
 					button.SetOnClickListener(ButtonClickListener.Instance.Value);
 					button.Tag = this;
 					SetNativeControl(button);
-
+					_textColorSwitcher = new TextColorSwitcher(button.TextColors);
 					button.AddOnAttachStateChangeListener(this);
 				}
 			}
@@ -255,22 +255,7 @@ namespace Xamarin.Forms.Platform.Android
 
 		void UpdateTextColor()
 		{
-			Color color = Element.TextColor;
-
-			if (color.IsDefault)
-			{
-				if (_buttonDefaulTextColors == null)
-					return;
-
-				NativeButton.SetTextColor(_buttonDefaulTextColors);
-			}
-			else
-			{
-				_buttonDefaulTextColors = _buttonDefaulTextColors ?? Control.TextColors;
-
-				// Set the new enabled state color, preserving the default disabled state color
-				NativeButton.SetTextColor(color.ToAndroidPreserveDisabled(_buttonDefaulTextColors));
-			}
+			_textColorSwitcher?.UpdateTextColor(Control, Element.TextColor);
 		}
 
 		class ButtonClickListener : Object, IOnClickListener
diff --git a/Xamarin.Forms.Platform.Android/Renderers/DatePickerRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/DatePickerRenderer.cs
index 11d9a0d0..5b0e0994 100644
--- a/Xamarin.Forms.Platform.Android/Renderers/DatePickerRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/DatePickerRenderer.cs
@@ -1,6 +1,7 @@
 using System;
 using System.ComponentModel;
 using Android.App;
+using Android.Content.Res;
 using Android.Widget;
 using AView = Android.Views.View;
 using Object = Java.Lang.Object;
@@ -11,6 +12,7 @@ namespace Xamarin.Forms.Platform.Android
 	{
 		DatePickerDialog _dialog;
 		bool _disposed;
+		TextColorSwitcher _textColorSwitcher;
 
 		public DatePickerRenderer()
 		{
@@ -47,24 +49,28 @@ namespace Xamarin.Forms.Platform.Android
 
 				textField.SetOnClickListener(TextFieldClickHandler.Instance);
 				SetNativeControl(textField);
+				_textColorSwitcher = new TextColorSwitcher(textField.TextColors); 
 			}
 
 			SetDate(Element.Date);
 
 			UpdateMinimumDate();
 			UpdateMaximumDate();
+			UpdateTextColor();
 		}
 
 		protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
 		{
 			base.OnElementPropertyChanged(sender, e);
 
-			if (e.PropertyName == "Date" || e.PropertyName == DatePicker.FormatProperty.PropertyName)
+			if (e.PropertyName == DatePicker.DateProperty.PropertyName || e.PropertyName == DatePicker.FormatProperty.PropertyName)
 				SetDate(Element.Date);
-			else if (e.PropertyName == "MinimumDate")
+			else if (e.PropertyName == DatePicker.MinimumDateProperty.PropertyName)
 				UpdateMinimumDate();
-			else if (e.PropertyName == "MaximumDate")
+			else if (e.PropertyName == DatePicker.MaximumDateProperty.PropertyName)
 				UpdateMaximumDate();
+			if (e.PropertyName == DatePicker.TextColorProperty.PropertyName)
+				UpdateTextColor();
 		}
 
 		internal override void OnFocusChangeRequested(object sender, VisualElement.FocusRequestArgs e)
@@ -141,6 +147,11 @@ namespace Xamarin.Forms.Platform.Android
 			}
 		}
 
+		void UpdateTextColor()
+		{
+			_textColorSwitcher?.UpdateTextColor(Control, Element.TextColor);
+		}
+
 		class TextFieldClickHandler : Object, IOnClickListener
 		{
 			public static readonly TextFieldClickHandler Instance = new TextFieldClickHandler();
diff --git a/Xamarin.Forms.Platform.Android/Renderers/PickerRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/PickerRenderer.cs
index b9114d22..e9cc3942 100644
--- a/Xamarin.Forms.Platform.Android/Renderers/PickerRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/PickerRenderer.cs
@@ -2,19 +2,21 @@ using System;
 using System.ComponentModel;
 using System.Linq;
 using Android.App;
+using Android.Content.Res;
 using Android.Views;
 using Android.Widget;
 using ADatePicker = Android.Widget.DatePicker;
 using ATimePicker = Android.Widget.TimePicker;
 using Object = Java.Lang.Object;
+using Orientation = Android.Widget.Orientation;
 
 namespace Xamarin.Forms.Platform.Android
 {
 	public class PickerRenderer : ViewRenderer<Picker, EditText>
 	{
 		AlertDialog _dialog;
-
 		bool _isDisposed;
+		TextColorSwitcher _textColorSwitcher;
 
 		public PickerRenderer()
 		{
@@ -44,9 +46,11 @@ namespace Xamarin.Forms.Platform.Android
 				{
 					var textField = new EditText(Context) { Focusable = false, Clickable = true, Tag = this };
 					textField.SetOnClickListener(PickerListener.Instance);
+					_textColorSwitcher = new TextColorSwitcher(textField.TextColors);
 					SetNativeControl(textField);
 				}
 				UpdatePicker();
+				UpdateTextColor();
 			}
 
 			base.OnElementChanged(e);
@@ -60,6 +64,8 @@ namespace Xamarin.Forms.Platform.Android
 				UpdatePicker();
 			if (e.PropertyName == Picker.SelectedIndexProperty.PropertyName)
 				UpdatePicker();
+			if (e.PropertyName == Picker.TextColorProperty.PropertyName)
+				UpdateTextColor();
 		}
 
 		internal override void OnFocusChangeRequested(object sender, VisualElement.FocusRequestArgs e)
@@ -148,6 +154,11 @@ namespace Xamarin.Forms.Platform.Android
 				((IVisualElementController)Element).NativeSizeChanged();
 		}
 
+		void UpdateTextColor()
+		{
+			_textColorSwitcher?.UpdateTextColor(Control, Element.TextColor);
+		}
+
 		class PickerListener : Object, IOnClickListener
 		{
 			public static readonly PickerListener Instance = new PickerListener();
diff --git a/Xamarin.Forms.Platform.Android/Renderers/TimePickerRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/TimePickerRenderer.cs
index cfa676d0..010eda72 100644
--- a/Xamarin.Forms.Platform.Android/Renderers/TimePickerRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/TimePickerRenderer.cs
@@ -1,6 +1,7 @@
 using System;
 using System.ComponentModel;
 using Android.App;
+using Android.Content.Res;
 using Android.Widget;
 using ADatePicker = Android.Widget.DatePicker;
 using ATimePicker = Android.Widget.TimePicker;
@@ -11,6 +12,7 @@ namespace Xamarin.Forms.Platform.Android
 	public class TimePickerRenderer : ViewRenderer<TimePicker, EditText>, TimePickerDialog.IOnTimeSetListener
 	{
 		AlertDialog _dialog;
+		TextColorSwitcher _textColorSwitcher;
 
 		public TimePickerRenderer()
 		{
@@ -36,17 +38,23 @@ namespace Xamarin.Forms.Platform.Android
 
 				textField.SetOnClickListener(TimePickerListener.Instance);
 				SetNativeControl(textField);
+				_textColorSwitcher = new TextColorSwitcher(textField.TextColors); 
 			}
 
 			SetTime(e.NewElement.Time);
+			UpdateTextColor();
 		}
 
 		protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
 		{
 			base.OnElementPropertyChanged(sender, e);
 
-			if (e.PropertyName == TimePicker.TimeProperty.PropertyName || e.PropertyName == TimePicker.FormatProperty.PropertyName)
+			if (e.PropertyName == TimePicker.TimeProperty.PropertyName ||
+			    e.PropertyName == TimePicker.FormatProperty.PropertyName)
 				SetTime(Element.Time);
+
+			if (e.PropertyName == TimePicker.TextColorProperty.PropertyName)
+				UpdateTextColor();
 		}
 
 		internal override void OnFocusChangeRequested(object sender, VisualElement.FocusRequestArgs e)
@@ -78,6 +86,11 @@ namespace Xamarin.Forms.Platform.Android
 			Control.Text = DateTime.Today.Add(time).ToString(Element.Format);
 		}
 
+		void UpdateTextColor()
+		{
+			_textColorSwitcher?.UpdateTextColor(Control, Element.TextColor);
+		}
+
 		class TimePickerListener : Object, IOnClickListener
 		{
 			public static readonly TimePickerListener Instance = new TimePickerListener();