Xamarin Theme

ChangeTheme.cs

				/// <summary>
        /// テーマ変更
        /// </summary>
        /// <param name="theme">theme</param>
        /// <exception cref="NotImplementedException"></exception>
        public void ChangeTheme(ThemeType theme)
        {
            if (MainPage == null) return;

            MainPage.Parent = null;

            ResourceDictionary t = null;
            switch (theme)
            {
                case ThemeType.Dark:
                    t = new DarkTheme();
                    break;
                case ThemeType.Light:
                    t = new LightTheme();
                    break;
                default:
                    throw new NotImplementedException();
            }
            Application.Current.Resources.MergedDictionaries.Add(t);

            MainPage.Parent = this;
        }

DarkTheme.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ResourceDictionary xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    x:Class="TaxPon.View.Themes.DarkTheme">
    <Color x:Key="BackgroundColor">Black</Color>
    <Color x:Key="ForegroundColor">#bdc3c7</Color>
    <Color x:Key="HeaderBackgroundColor">#20202a</Color>
    <Color x:Key="HeaderForegroundColor">#bdc3c7</Color>
    <Color x:Key="HeaderLogoColor">#1abc9c</Color>
    <Color x:Key="ListItemBackgroundColor">#1c1c1c</Color>
    <Color x:Key="ListItemTitleColor">#2980b9</Color>
</ResourceDictionary>

DarkTheme.xaml.cs

	[XamlCompilation(XamlCompilationOptions.Compile)]
	public partial class DarkTheme : ResourceDictionary
  {
		public DarkTheme ()
		{
			InitializeComponent ();
		}
	}

LightTheme.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ResourceDictionary xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    x:Class="TaxPon.View.Themes.LightTheme">
    <Color x:Key="BackgroundColor">#ecf0f1</Color>
    <Color x:Key="ForegroundColor">#33333c</Color>
    <Color x:Key="HeaderBackgroundColor">#2c3e50</Color>
    <Color x:Key="HeaderForegroundColor">#bdc3c7</Color>
    <Color x:Key="HeaderLogoColor">#1abc9c</Color>
    <Color x:Key="ListItemBackgroundColor">#bdc3c7</Color>
    <Color x:Key="ListItemTitleColor">#2980b9</Color>
</ResourceDictionary>

	

LightTheme.xaml.cs

[XamlCompilation(XamlCompilationOptions.Compile)]
	public partial class LightTheme : ResourceDictionary
	{
		public LightTheme ()
		{
			InitializeComponent ();
		}
	}

ThemeType.cs

public enum ThemeType
{
	Dark,
	Light,
}