initial

Billing.Shared/App.cs

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+using Billing.Languages;
+using Billing.Themes;
+using Xamarin.Essentials;
+using Xamarin.Forms;
+
+namespace Billing;
+
+public class App : Application
+{
+    public static AppTheme CurrentTheme { get; private set; }
+    public static PlatformCulture CurrentCulture { get; private set; }
+
+    public App()
+    {
+        CurrentCulture = new PlatformCulture();
+        InitResources();
+
+        MainPage = new MainShell();
+        Shell.Current.GoToAsync("//Bills");
+    }
+
+    protected override void OnStart()
+    {
+    }
+
+    protected override void OnResume()
+    {
+        SetTheme(AppInfo.RequestedTheme);
+    }
+
+    private void InitResources()
+    {
+        var theme = AppInfo.RequestedTheme;
+        SetTheme(theme, true);
+    }
+
+    private void SetTheme(AppTheme theme, bool force = false)
+    {
+        if (force || theme != CurrentTheme)
+        {
+            CurrentTheme = theme;
+        }
+        else
+        {
+            return;
+        }
+        Helper.Debug($"application theme: {theme}");
+
+        BaseTheme instance;
+        if (theme == AppTheme.Dark)
+        {
+            instance = Dark.Instance;
+        }
+        else
+        {
+            instance = Light.Instance;
+        }
+        // TODO: status bar
+        Resources = instance;
+    }
+}

Billing.Shared/AssemblyInfo.cs

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+using Xamarin.Forms.Xaml;
+
+[assembly: XamlCompilation(XamlCompilationOptions.Compile)]

Billing.Shared/Billing.Shared.projitems

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+<?xml version="1.0" encoding="utf-8"?>
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <MSBuildAllProjects Condition="'$(MSBuildVersion)' == '' Or '$(MSBuildVersion)' &lt; '16.0'">$(MSBuildAllProjects);$(MSBuildThisFileFullPath)</MSBuildAllProjects>
+    <HasSharedItems>true</HasSharedItems>
+    <SharedGUID>6ac75d01-70d6-4a07-8685-bc52afd97a7a</SharedGUID>
+  </PropertyGroup>
+  <PropertyGroup Label="Configuration">
+    <Import_RootNamespace>Billing</Import_RootNamespace>
+  </PropertyGroup>
+  <ItemGroup>
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Languages\en.xml" />
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Languages\zh-CN.xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildThisFileDirectory)App.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)AssemblyInfo.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Helper.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Languages\PlatformCulture.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Languages\Resource.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)MainShell.xaml.cs">
+      <DependentUpon>MainShell.xaml</DependentUpon>
+    </Compile>
+    <Compile Include="$(MSBuildThisFileDirectory)Themes\BaseTheme.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Themes\Dark.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Themes\Light.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)UI\BillingDate.xaml.cs">
+      <DependentUpon>BillingDate.xaml</DependentUpon>
+    </Compile>
+    <Compile Include="$(MSBuildThisFileDirectory)UI\BillingPage.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)UI\Converters.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)UI\CustomControl.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)UI\Definition.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Views\AccountPage.xaml.cs">
+      <DependentUpon>AccountPage.xaml</DependentUpon>
+    </Compile>
+    <Compile Include="$(MSBuildThisFileDirectory)Views\AddBillPage.xaml.cs">
+      <DependentUpon>AddBillPage.xaml</DependentUpon>
+    </Compile>
+    <Compile Include="$(MSBuildThisFileDirectory)Views\BillPage.xaml.cs">
+      <DependentUpon>BillPage.xaml</DependentUpon>
+    </Compile>
+    <Compile Include="$(MSBuildThisFileDirectory)Views\SettingPage.xaml.cs">
+      <DependentUpon>SettingPage.xaml</DependentUpon>
+    </Compile>
+  </ItemGroup>
+  <ItemGroup>
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)MainShell.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)UI\BillingDate.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Views\AccountPage.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Views\AddBillPage.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Views\BillPage.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Views\SettingPage.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
+  </ItemGroup>
+</Project>

Billing.Shared/Billing.Shared.shproj

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+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>6ac75d01-70d6-4a07-8685-bc52afd97a7a</ProjectGuid>
+    <MinimumVisualStudioVersion>14.0</MinimumVisualStudioVersion>
+  </PropertyGroup>
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.Common.Default.props" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.Common.props" />
+  <PropertyGroup />
+  <Import Project="Billing.Shared.projitems" Label="Shared" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.CSharp.targets" />
+</Project>

Billing.Shared/Helper.cs

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+using System;
+
+namespace Billing;
+
+internal static class Helper
+{
+    public static void Debug(string message)
+    {
+        var time = DateTime.Now.ToString("HH:mm:ss.fff");
+        System.Diagnostics.Debug.WriteLine($"[{time}] - {message}");
+    }
+
+    public static void Error(string category, Exception ex)
+    {
+        Error(category, ex?.Message ?? "unknown error");
+    }
+
+    public static void Error(string category, string message)
+    {
+        var time = DateTime.Now.ToString("HH:mm:ss.fff");
+        System.Diagnostics.Debug.Fail($"[{time}] - {category}", message);
+    }
+}

Billing.Shared/Languages/PlatformCulture.cs

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+namespace Billing.Languages
+{
+    public partial class PlatformCulture
+    {
+        public string PlatformString { get; set; }
+        public string LanguageCode { get; set; }
+        public string LocaleCode { get; set; }
+
+        public string Language => string.IsNullOrEmpty(LocaleCode) ? LanguageCode : LanguageCode + "-" + LocaleCode;
+
+        public partial string GetNamespace();
+        public partial void Init();
+
+        public PlatformCulture()
+        {
+            Init();
+        }
+
+        private void Init(string cultureString) 
+        {
+            if (string.IsNullOrEmpty(cultureString))
+            {
+                cultureString = "zh-CN";
+            }
+
+            PlatformString = cultureString.Replace('_', '-');
+            if (PlatformString.Contains('-'))
+            {
+                var parts = PlatformString.Split('-');
+                LanguageCode = parts[0];
+                LocaleCode = parts[^1];
+            }
+            else
+            {
+                LanguageCode = PlatformString;
+                LocaleCode = string.Empty;
+            }
+        }
+
+        private string ToDotnetFallbackLanguage()
+        {
+            string netLanguage = LanguageCode switch
+            {
+                // fallback to Portuguese (Portugal)
+                "pt" => "pt-PT",
+                // equivalent to German (Switzerland) for this app
+                "gsw" => "de-CH",
+
+                // add more application-specific cases here (if required)
+                // ONLY use cultures that have been tested and known to work
+
+                // use the first part of the identifier (two chars, usually);
+                _ => LanguageCode,
+            };
+            Helper.Debug($".NET Fallback Language/Locale: {LanguageCode} to {netLanguage} (application-specific)");
+            return netLanguage;
+        }
+
+        public override string ToString() => PlatformString;
+    }
+}

Billing.Shared/Languages/Resource.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Xml;
+using Xamarin.Forms;
+using Xamarin.Forms.Xaml;
+
+namespace Billing.Languages
+{
+    internal class Resource
+    {
+        public static string TitleDateFormat => Text(nameof(TitleDateFormat));
+
+        static readonly Dictionary<string, LanguageResource> dict = new();
+
+        public static string Text(string name, params object[] args)
+        {
+            string current = App.CurrentCulture.PlatformString;
+            if (!dict.TryGetValue(current, out LanguageResource lang))
+            {
+                lang = new LanguageResource(App.CurrentCulture);
+                dict.Add(current, lang);
+            }
+            if (args == null || args.Length == 0)
+            {
+                return lang[name];
+            }
+            return string.Format(lang[name], args);
+        }
+
+        private class LanguageResource
+        {
+            private readonly Dictionary<string, string> strings;
+
+            public string this[string key]
+            {
+                get
+                {
+                    if (strings?.TryGetValue(key, out string val) == true)
+                    {
+                        return val;
+                    }
+                    return key;
+                }
+            }
+
+            public LanguageResource(PlatformCulture lang)
+            {
+                try
+                {
+                    var ns = lang.GetNamespace();
+                    var langId = $"{ns}.Languages.{lang.Language}.xml";
+                    var langCodeId = $"{ns}.Languages.{lang.LanguageCode}.xml";
+                    var assembly = typeof(LanguageResource).Assembly;
+                    var name = assembly.GetManifestResourceNames().FirstOrDefault(n =>
+                        string.Equals(n, langId, StringComparison.OrdinalIgnoreCase) ||
+                        string.Equals(n, langCodeId, StringComparison.OrdinalIgnoreCase));
+                    if (name == null)
+                    {
+                        name = $"{ns}.Languages.zh-CN.xml";
+                    }
+                    var xml = new XmlDocument();
+                    using (var stream = assembly.GetManifestResourceStream(name))
+                    {
+                        xml.Load(stream);
+                    }
+                    strings = new Dictionary<string, string>();
+                    foreach (XmlElement ele in xml.DocumentElement)
+                    {
+                        strings[ele.Name] = ele.InnerText;
+                    }
+                }
+                catch (Exception ex)
+                {
+                    Helper.Error("language.ctor", $"failed to load json resource: {lang}, {ex.Message}");
+                }
+            }
+        }
+    }
+
+    [ContentProperty(nameof(Text))]
+    public class TextExtension : IMarkupExtension
+    {
+        public string Text { get; set; }
+
+        public object ProvideValue(IServiceProvider serviceProvider)
+        {
+            if (Text == null)
+            {
+                return string.Empty;
+            }
+            return Resource.Text(Text);
+        }
+    }
+}

Billing.Shared/Languages/en.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<root>
+	<Accounts>Accounts</Accounts>
+	<Bills>Bills</Bills>
+	<Settings>Settings</Settings>
+	<Sunday>Su</Sunday>
+	<Monday>Mo</Monday>
+	<Tuesday>Tu</Tuesday>
+	<Wednesday>We</Wednesday>
+	<Thursday>Th</Thursday>
+	<Friday>Fr</Friday>
+	<Saturday>Sa</Saturday>
+	<NoRecords>Bills not yet generated</NoRecords>
+	<Memo>Click here to record</Memo>
+	<TitleDateFormat>MM/dd/yyyy</TitleDateFormat>
+</root>

Billing.Shared/Languages/zh-CN.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<root>
+	<Accounts>账户</Accounts>
+	<Bills>账单</Bills>
+	<Settings>设置</Settings>
+	<Sunday>周日</Sunday>
+	<Monday>周一</Monday>
+	<Tuesday>周二</Tuesday>
+	<Wednesday>周三</Wednesday>
+	<Thursday>周四</Thursday>
+	<Friday>周五</Friday>
+	<Saturday>周六</Saturday>
+	<NoRecords>还未产生账单</NoRecords>
+	<Memo>点此记录</Memo>
+	<TitleDateFormat>yyyy年MM月dd日</TitleDateFormat>
+</root>

Billing.Shared/MainShell.xaml

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+<?xml version="1.0" encoding="utf-8" ?>
+<Shell xmlns="http://xamarin.com/schemas/2014/forms"
+       xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+       xmlns:v="clr-namespace:Billing.Views"
+       xmlns:r="clr-namespace:Billing.Languages"
+       x:Class="Billing.MainShell"
+       BackgroundColor="{DynamicResource WindowBackgroundColor}"
+       ForegroundColor="{DynamicResource PrimaryColor}"
+       TitleColor="{DynamicResource PrimaryColor}"
+       Shell.NavBarHasShadow="True">
+
+    <TabBar>
+        <ShellContent ContentTemplate="{DataTemplate v:AccountPage}" Route="Accounts" Title="{r:Text Accounts}" Icon="wallet.png"/>
+        <ShellContent ContentTemplate="{DataTemplate v:BillPage}" Route="Bills" Title="{r:Text Bills}" Icon="bill.png"/>
+        <ShellContent ContentTemplate="{DataTemplate v:SettingPage}" Route="Settings" Title="{r:Text Settings}" Icon="settings.png"/>
+    </TabBar>
+
+</Shell>

Billing.Shared/MainShell.xaml.cs

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+using Xamarin.Forms;
+
+namespace Billing;
+
+public partial class MainShell : Shell
+{
+    public MainShell()
+    {
+        InitializeComponent();
+    }
+}

Billing.Shared/Themes/BaseTheme.cs

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+using Billing.UI;
+using Xamarin.Forms;
+
+namespace Billing.Themes;
+
+public abstract class BaseTheme : ResourceDictionary
+{
+    public const string CascadiaFontRegular = nameof(CascadiaFontRegular);
+    public const string CascadiaFontBold = nameof(CascadiaFontBold);
+    public const string RobotoCondensedFontRegular = nameof(RobotoCondensedFontRegular);
+    public const string RobotoCondensedFontBold = nameof(RobotoCondensedFontBold);
+    public const string WindowBackgroundColor = nameof(WindowBackgroundColor);
+    public const string PromptBackgroundColor = nameof(PromptBackgroundColor);
+    public const string PrimaryColor = nameof(PrimaryColor);
+    public const string SecondaryColor = nameof(SecondaryColor);
+    public const string TabBarBackgroundColor = nameof(TabBarBackgroundColor);
+    public const string TabBarTitleColor = nameof(TabBarTitleColor);
+    public const string TabBarUnselectedColor = nameof(TabBarUnselectedColor);
+    public const string OutRangeDayColor = nameof(OutRangeDayColor);
+    public const string TextColor = nameof(TextColor);
+    public const string WeekendColor = nameof(WeekendColor);
+
+    protected abstract Color PrimaryMauiColor { get; }
+    protected abstract Color SecondaryMauiColor { get; }
+
+    protected void InitResources()
+    {
+        var robotoRegularFontFamily = Definition.GetRobotoCondensedRegularFontFamily();
+        Add(CascadiaFontRegular, Definition.GetCascadiaRegularFontFamily());
+        Add(CascadiaFontBold, Definition.GetCascadiaBoldFontFamily());
+        Add(RobotoCondensedFontRegular, Definition.GetRobotoCondensedRegularFontFamily());
+        Add(RobotoCondensedFontBold, Definition.GetRobotoCondensedBoldFontFamily());
+
+        Add(PrimaryColor, PrimaryMauiColor);
+        Add(SecondaryColor, SecondaryMauiColor);
+        Add(TabBarTitleColor, PrimaryMauiColor);
+
+        Add(new Style(typeof(Label))
+        {
+            Setters =
+            {
+                new Setter { Property = Label.FontSizeProperty, Value = Device.GetNamedSize(NamedSize.Small, typeof(Label)) },
+                new Setter { Property = Label.TextColorProperty, Value = PrimaryMauiColor },
+                new Setter { Property = Label.FontFamilyProperty, Value = robotoRegularFontFamily }
+            }
+        });
+        Add(new Style(typeof(Button))
+        {
+            Setters =
+            {
+                new Setter { Property = Button.TextColorProperty, Value = SecondaryMauiColor },
+                new Setter { Property = Button.FontFamilyProperty, Value = robotoRegularFontFamily },
+                new Setter { Property = VisualElement.BackgroundColorProperty, Value = PrimaryMauiColor },
+                new Setter { Property = Button.PaddingProperty, Value = new Thickness(14, 10) }
+            }
+        });
+        Add(new Style(typeof(TintImage))
+        {
+            Setters =
+            {
+                new Setter { Property = TintImage.PrimaryColorProperty, Value = PrimaryMauiColor }
+            }
+        });
+    }
+}

Billing.Shared/Themes/Dark.cs

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+using Xamarin.Forms;
+
+namespace Billing.Themes;
+
+public class Dark : BaseTheme
+{
+    private static Dark _instance;
+
+    public static Dark Instance => _instance ??= new Dark();
+
+    protected override Color PrimaryMauiColor => Color.White;
+    protected override Color SecondaryMauiColor => Color.LightGray;
+
+    public Dark()
+    {
+        InitColors();
+        InitResources();
+    }
+
+    private void InitColors()
+    {
+        Add(WindowBackgroundColor, Color.Black);
+        Add(PromptBackgroundColor, Color.FromRgb(0x1f, 0x1f, 0x1f));
+        Add(TabBarBackgroundColor, Color.Black);
+        Add(TabBarUnselectedColor, Color.FromRgb(0x82, 0x82, 0x82));
+        Add(OutRangeDayColor, Color.DarkGray);
+        Add(TextColor, Color.FromRgb(0xcc, 0xcc, 0xcc));
+        Add(WeekendColor, Color.FromRgb(211, 5, 5));
+
+        Add(new Style(typeof(TabBar))
+        {
+            Setters =
+            {
+                new Setter { Property = Shell.TabBarBackgroundColorProperty, Value = Color.Black },
+                new Setter { Property = Shell.TabBarTitleColorProperty, Value = PrimaryMauiColor },
+                new Setter { Property = Shell.TabBarUnselectedColorProperty, Value = Color.FromRgb(0x82, 0x82, 0x82) }
+            }
+        });
+    }
+}

Billing.Shared/Themes/Light.cs

@@ -0,0 +1,40 @@
+using Xamarin.Forms;
+
+namespace Billing.Themes;
+
+public class Light : BaseTheme
+{
+    private static Light _instance;
+
+    public static Light Instance => _instance ??= new Light();
+
+    protected override Color PrimaryMauiColor => Color.FromRgb(0x18, 0x31, 0x53);
+    protected override Color SecondaryMauiColor => Color.White;
+
+    public Light()
+    {
+        InitColors();
+        InitResources();
+    }
+
+    private void InitColors()
+    {
+        Add(WindowBackgroundColor, Color.White);
+        Add(PromptBackgroundColor, Color.FromRgb(0xe0, 0xe0, 0xe0));
+        Add(TabBarBackgroundColor, Color.White);
+        Add(TabBarUnselectedColor, Color.FromRgb(0x82, 0x82, 0x82));
+        Add(OutRangeDayColor, Color.LightGray);
+        Add(TextColor, Color.FromRgb(0x33, 0x33, 0x33));
+        Add(WeekendColor, Color.FromRgb(211, 64, 85));
+
+        Add(new Style(typeof(TabBar))
+        {
+            Setters =
+            {
+                new Setter { Property = Shell.TabBarBackgroundColorProperty, Value = Color.White },
+                new Setter { Property = Shell.TabBarTitleColorProperty, Value = PrimaryMauiColor },
+                new Setter { Property = Shell.TabBarUnselectedColorProperty, Value = Color.FromRgb(0x82, 0x82, 0x82) }
+            }
+        });
+    }
+}

Billing.Shared/UI/BillingDate.xaml

@@ -0,0 +1,76 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentView xmlns="http://xamarin.com/schemas/2014/forms"
+             xmlns:r="clr-namespace:Billing.Languages"
+             xmlns:ui="clr-namespace:Billing.UI"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="Billing.UI.BillingDate"
+             x:DataType="ui:BillingDate"
+             x:Name="billingDate"
+             BindingContext="{x:Reference billingDate}">
+    <ContentView.Resources>
+        <Style x:Key="centerLabel" TargetType="Label">
+            <Setter Property="HorizontalOptions" Value="Center"/>
+            <Setter Property="FontSize" Value="Small"/>
+            <Setter Property="TextColor" Value="{DynamicResource TextColor}"/>
+        </Style>
+        <Style x:Key="dateLabel" TargetType="Label">
+            <Setter Property="HorizontalOptions" Value="Center"/>
+        </Style>
+        <ControlTemplate x:Key="weekDay">
+            <Grid Padding="0, 8, 0, 0" RowDefinitions="Auto, 3" RowSpacing="0">
+                <Grid.GestureRecognizers>
+                    <TapGestureRecognizer Command="{Binding OnDayTapped, Source={x:Reference billingDate}}" CommandParameter="{TemplateBinding BillingDay}"/>
+                </Grid.GestureRecognizers>
+                <Label Style="{StaticResource dateLabel}" Text="{TemplateBinding BillingDay.Text}"
+                       TextColor="{DynamicResource TextColor}"
+                       FontFamily="{TemplateBinding BillingDay.FontFamily}"
+                       Opacity="{TemplateBinding BillingDay.TextOpacity}"/>
+                <StackLayout Grid.Row="1"
+                             IsVisible="{TemplateBinding BillingDay.IsSelected}"
+                             BackgroundColor="{DynamicResource PrimaryColor}"
+                             Opacity="{TemplateBinding BillingDay.Opacity}"/>
+            </Grid>
+        </ControlTemplate>
+        <ControlTemplate x:Key="weekEnd">
+            <Grid Padding="0, 8, 0, 0" RowDefinitions="Auto, 3" RowSpacing="0">
+                <Grid.GestureRecognizers>
+                    <TapGestureRecognizer Command="{Binding OnDayTapped, Source={x:Reference billingDate}}" CommandParameter="{TemplateBinding BillingDay}"/>
+                </Grid.GestureRecognizers>
+                <Label Style="{StaticResource dateLabel}" Text="{TemplateBinding BillingDay.Text}"
+                       TextColor="{DynamicResource WeekendColor}"
+                       FontFamily="{TemplateBinding BillingDay.FontFamily}"
+                       Opacity="{TemplateBinding BillingDay.TextOpacity}"/>
+                <StackLayout Grid.Row="1"
+                             IsVisible="{TemplateBinding BillingDay.IsSelected}"
+                             BackgroundColor="{DynamicResource PrimaryColor}"
+                             Opacity="{TemplateBinding BillingDay.Opacity}"/>
+            </Grid>
+        </ControlTemplate>
+        <Style TargetType="ui:BillingDayView">
+            <Setter Property="ControlTemplate" Value="{StaticResource weekDay}"/>
+        </Style>
+    </ContentView.Resources>
+    <ContentView.Content>
+        <Grid Padding="0, 8, 0, 4" ColumnDefinitions="*,*,*,*,*,*,*" RowDefinitions="Auto, Auto">
+            <Grid.GestureRecognizers>
+                <PanGestureRecognizer PanUpdated="OnPanUpdated"/>
+            </Grid.GestureRecognizers>
+
+            <Label Grid.Column="0" Text="{r:Text Sunday}" Style="{StaticResource centerLabel}"/>
+            <Label Grid.Column="1" Text="{r:Text Monday}" Style="{StaticResource centerLabel}"/>
+            <Label Grid.Column="2" Text="{r:Text Tuesday}" Style="{StaticResource centerLabel}"/>
+            <Label Grid.Column="3" Text="{r:Text Wednesday}" Style="{StaticResource centerLabel}"/>
+            <Label Grid.Column="4" Text="{r:Text Thursday}" Style="{StaticResource centerLabel}"/>
+            <Label Grid.Column="5" Text="{r:Text Friday}" Style="{StaticResource centerLabel}"/>
+            <Label Grid.Column="6" Text="{r:Text Saturday}" Style="{StaticResource centerLabel}"/>
+
+            <ui:BillingDayView Grid.Row="1" Grid.Column="0" BillingDay="{Binding Sunday}" ControlTemplate="{StaticResource weekEnd}"/>
+            <ui:BillingDayView Grid.Row="1" Grid.Column="1" BillingDay="{Binding Monday}"/>
+            <ui:BillingDayView Grid.Row="1" Grid.Column="2" BillingDay="{Binding Tuesday}"/>
+            <ui:BillingDayView Grid.Row="1" Grid.Column="3" BillingDay="{Binding Wednesday}"/>
+            <ui:BillingDayView Grid.Row="1" Grid.Column="4" BillingDay="{Binding Thursday}"/>
+            <ui:BillingDayView Grid.Row="1" Grid.Column="5" BillingDay="{Binding Friday}"/>
+            <ui:BillingDayView Grid.Row="1" Grid.Column="6" BillingDay="{Binding Saturday}" ControlTemplate="{StaticResource weekEnd}"/>
+        </Grid>
+    </ContentView.Content>
+</ContentView>

Billing.Shared/UI/BillingDate.xaml.cs

@@ -0,0 +1,290 @@
+using Billing.Themes;
+using System;
+using Xamarin.Forms;
+
+namespace Billing.UI;
+
+public partial class BillingDate : ContentView
+{
+    #region UI Properties
+
+    private static readonly BindableProperty SundayProperty = BindableProperty.Create(nameof(Sunday), typeof(BillingDay), typeof(BillingDate));
+    private static readonly BindableProperty MondayProperty = BindableProperty.Create(nameof(Monday), typeof(BillingDay), typeof(BillingDate));
+    private static readonly BindableProperty TuesdayProperty = BindableProperty.Create(nameof(Tuesday), typeof(BillingDay), typeof(BillingDate));
+    private static readonly BindableProperty WednesdayProperty = BindableProperty.Create(nameof(Wednesday), typeof(BillingDay), typeof(BillingDate));
+    private static readonly BindableProperty ThursdayProperty = BindableProperty.Create(nameof(Thursday), typeof(BillingDay), typeof(BillingDate));
+    private static readonly BindableProperty FridayProperty = BindableProperty.Create(nameof(Friday), typeof(BillingDay), typeof(BillingDate));
+    private static readonly BindableProperty SaturdayProperty = BindableProperty.Create(nameof(Saturday), typeof(BillingDay), typeof(BillingDate));
+
+    public BillingDay Sunday => (BillingDay)GetValue(SundayProperty);
+    public BillingDay Monday => (BillingDay)GetValue(MondayProperty);
+    public BillingDay Tuesday => (BillingDay)GetValue(TuesdayProperty);
+    public BillingDay Wednesday => (BillingDay)GetValue(WednesdayProperty);
+    public BillingDay Thursday => (BillingDay)GetValue(ThursdayProperty);
+    public BillingDay Friday => (BillingDay)GetValue(FridayProperty);
+    public BillingDay Saturday => (BillingDay)GetValue(SaturdayProperty);
+
+    #endregion
+
+    private static BindableProperty GetWeekProperty(int week)
+    {
+        return (DayOfWeek)week switch
+        {
+            DayOfWeek.Monday => MondayProperty,
+            DayOfWeek.Tuesday => TuesdayProperty,
+            DayOfWeek.Wednesday => WednesdayProperty,
+            DayOfWeek.Thursday => ThursdayProperty,
+            DayOfWeek.Friday => FridayProperty,
+            DayOfWeek.Saturday => SaturdayProperty,
+            _ => SundayProperty
+        };
+    }
+
+    public static readonly BindableProperty LocatedDateProperty = BindableProperty.Create(nameof(LocatedDate), typeof(DateTime), typeof(BillingDate), propertyChanged: OnLocatedDatePropertyChanged);
+    public static readonly BindableProperty SelectedDateProperty = BindableProperty.Create(nameof(SelectedDate), typeof(DateTime), typeof(BillingDate), propertyChanged: OnSelectedDatePropertyChanged);
+
+    private static void OnLocatedDatePropertyChanged(BindableObject obj, object old, object @new)
+    {
+        if (obj is BillingDate billingDate && @new is DateTime date)
+        {
+            var week = (int)date.DayOfWeek;
+            var tmpDate = date.AddDays(-week);
+            for (var i = 0; i < 7; i++)
+            {
+                var prop = GetWeekProperty(i);
+                var day = new BillingDay(tmpDate);
+                billingDate.SetValue(prop, day);
+                tmpDate = tmpDate.AddDays(1);
+            }
+        }
+    }
+
+    private static void OnSelectedDatePropertyChanged(BindableObject obj, object old, object @new)
+    {
+        if (obj is BillingDate billingDate && @new is DateTime selected)
+        {
+            for (var i = 0; i < 7; i++)
+            {
+                var prop = GetWeekProperty(i);
+                var day = (BillingDay)billingDate.GetValue(prop);
+                day.Refresh(selected);
+            }
+        }
+    }
+
+    public DateTime LocatedDate
+    {
+        get => (DateTime)GetValue(LocatedDateProperty);
+        set => SetValue(LocatedDateProperty, value);
+    }
+    public DateTime SelectedDate
+    {
+        get => (DateTime)GetValue(SelectedDateProperty);
+        set => SetValue(SelectedDateProperty, value);
+    }
+
+    public Command OnDayTapped { get; }
+
+    public event EventHandler<DateEventArgs> DateSelected;
+
+    private DateTime lastDate;
+    private double? x1;
+    private double x2;
+
+    public BillingDate()
+    {
+        OnDayTapped = new Command(OnDayChanged);
+
+        InitializeComponent();
+    }
+
+    public void SetDateTime(DateTime selectedDate, DateTime? locatedDate = null)
+    {
+        if (locatedDate != null)
+        {
+            LocatedDate = locatedDate.Value;
+        }
+        else
+        {
+            LocatedDate = selectedDate;
+        }
+        SelectedDate = selectedDate;
+        DateSelected?.Invoke(this, new DateEventArgs(selectedDate));
+    }
+
+    private void OnDayChanged(object o)
+    {
+        var selected = SelectedDate;
+        if (o is BillingDay day && (selected.Year != day.Date.Year || selected.DayOfYear != day.Date.DayOfYear))
+        {
+            for (var i = 0; i < 7; i++)
+            {
+                var d = (BillingDay)GetValue(GetWeekProperty(i));
+                if (d.IsSelected)
+                {
+                    this.AbortAnimation("unselected");
+                    this.Animate("unselected", v =>
+                    {
+                        d.Opacity = v;
+                    },
+                    start: 1, end: 0,
+                    easing: Easing.CubicOut,
+                    finished: (v, b) =>
+                    {
+                        d.Opacity = 0;
+                        d.IsSelected = false;
+                    });
+                }
+            }
+            SelectedDate = day.Date;
+            this.AbortAnimation("selected");
+            this.Animate("selected", v =>
+            {
+                day.Opacity = v;
+            },
+            start: 0, end: 1,
+            easing: Easing.CubicOut,
+            finished: (v, b) =>
+            {
+                day.Opacity = 1;
+            });
+            DateSelected?.Invoke(this, new DateEventArgs(day.Date));
+        }
+    }
+
+    private void OnPanUpdated(object sender, PanUpdatedEventArgs e)
+    {
+        if (e.StatusType == GestureStatus.Started)
+        {
+            lastDate = DateTime.Now;
+            x1 = null;
+        }
+        else if (e.StatusType == GestureStatus.Running)
+        {
+            if (x1 == null)
+            {
+                x1 = e.TotalX;
+            }
+            x2 = e.TotalX;
+        }
+        else if (e.StatusType == GestureStatus.Completed)
+        {
+            if (x1 == null)
+            {
+                return;
+            }
+            var totalX = x2 - x1.Value;
+            x1 = null;
+            var ms = (DateTime.Now - lastDate).TotalMilliseconds;
+            var speed = totalX / ms;
+            Helper.Debug($"completed, speed: {speed}");
+            if (speed < -0.7)
+            {
+                LocatedDate = LocatedDate.AddDays(7);
+            }
+            else if (speed > 0.7)
+            {
+                LocatedDate = LocatedDate.AddDays(-7);
+            }
+            OnSelectedDatePropertyChanged(this, null, SelectedDate);
+        }
+    }
+}
+
+public class DateEventArgs : EventArgs
+{
+    public DateTime Date { get; }
+
+    public DateEventArgs(DateTime date)
+    {
+        Date = date;
+    }
+}
+
+public class BillingDayView : ContentView
+{
+    public static readonly BindableProperty BillingDayProperty = BindableProperty.Create(nameof(BillingDay), typeof(BillingDay), typeof(BillingDayView));
+    public static readonly BindableProperty CommandProperty = BindableProperty.Create(nameof(Command), typeof(Command), typeof(BillingDayView));
+
+    public BillingDay BillingDay
+    {
+        get => (BillingDay)GetValue(BillingDayProperty);
+        set => SetValue(BillingDayProperty, value);
+    }
+    public Command Command
+    {
+        get => (Command)GetValue(CommandProperty);
+        set => SetValue(CommandProperty, value);
+    }
+}
+
+public class BillingDay : BindableObject
+{
+    private static readonly BindableProperty DateProperty = BindableProperty.Create(nameof(Date), typeof(DateTime), typeof(BillingDay), propertyChanged: OnDatePropertyChanged);
+    private static readonly BindableProperty TextProperty = BindableProperty.Create(nameof(Text), typeof(string), typeof(BillingDay));
+    private static readonly BindableProperty FontFamilyProperty = BindableProperty.Create(nameof(FontFamily), typeof(string), typeof(BillingDay), defaultValue: Definition.GetCascadiaRegularFontFamily());
+    private static readonly BindableProperty IsSelectedProperty = BindableProperty.Create(nameof(IsSelected), typeof(bool), typeof(BillingDay));
+    private static readonly BindableProperty OpacityProperty = BindableProperty.Create(nameof(Opacity), typeof(double), typeof(BillingDay), defaultValue: 1.0);
+    private static readonly BindableProperty TextOpacityProperty = BindableProperty.Create(nameof(TextOpacity), typeof(double), typeof(BillingDay), defaultValue: 1.0);
+
+    private static void OnDatePropertyChanged(BindableObject obj, object old, object @new)
+    {
+        if (obj is BillingDay day && @new is DateTime date)
+        {
+            if (date.Day == 1)
+            {
+                day.SetValue(TextProperty, date.ToString("MMM"));
+            }
+            else
+            {
+                day.SetValue(TextProperty, date.Day.ToString());
+            }
+        }
+    }
+
+    public DateTime Date
+    {
+        get => (DateTime)GetValue(DateProperty);
+        set => SetValue(DateProperty, value);
+    }
+    public string Text => (string)GetValue(TextProperty);
+    public string FontFamily => (string)GetValue(FontFamilyProperty);
+    public bool IsSelected
+    {
+        get => (bool)GetValue(IsSelectedProperty);
+        set => SetValue(IsSelectedProperty, value);
+    }
+    public double Opacity
+    {
+        get => (double)GetValue(OpacityProperty);
+        set => SetValue(OpacityProperty, value);
+    }
+    public double TextOpacity => (double)GetValue(TextOpacityProperty);
+
+    public BillingDay(DateTime date)
+    {
+        Date = date;
+    }
+
+    public void Refresh(DateTime selected)
+    {
+        var date = Date;
+        if (date.Year == selected.Year && date.DayOfYear == selected.DayOfYear)
+        {
+            SetValue(IsSelectedProperty, true);
+            SetValue(FontFamilyProperty, Definition.GetCascadiaBoldFontFamily());
+        }
+        else
+        {
+            SetValue(FontFamilyProperty, Definition.GetCascadiaRegularFontFamily());
+        }
+        if (date.Year == selected.Year && date.Month == selected.Month)
+        {
+            SetValue(TextOpacityProperty, 1.0);
+        }
+        else
+        {
+            SetValue(TextOpacityProperty, .4);
+        }
+    }
+}

Billing.Shared/UI/BillingPage.cs

@@ -0,0 +1,12 @@
+using Billing.Themes;
+using Xamarin.Forms;
+
+namespace Billing.UI;
+
+public abstract class BillingPage : ContentPage
+{
+    public BillingPage()
+    {
+        SetDynamicResource(BackgroundColorProperty, BaseTheme.WindowBackgroundColor);
+    }
+}

Billing.Shared/UI/Converters.cs

@@ -0,0 +1,23 @@
+using Billing.Languages;
+using System;
+using System.Globalization;
+using Xamarin.Forms;
+
+namespace Billing.UI;
+
+public class TitleDateConverter : IValueConverter
+{
+    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+    {
+        if (value is DateTime date)
+        {
+            return date.ToString(Resource.TitleDateFormat);
+        }
+        return value;
+    }
+
+    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+    {
+        return value;
+    }
+}

Billing.Shared/UI/CustomControl.cs

@@ -0,0 +1,31 @@
+using System;
+using Xamarin.Forms;
+
+namespace Billing.UI;
+
+public class TintImage : Image
+{
+    public static readonly BindableProperty PrimaryColorProperty = BindableProperty.Create(nameof(PrimaryColor), typeof(Color?), typeof(TintImage));
+
+    public Color? PrimaryColor
+    {
+        get => (Color?)GetValue(PrimaryColorProperty);
+        set => SetValue(PrimaryColorProperty, value);
+    }
+}
+
+public class LongPressButton : Button
+{
+    public event EventHandler LongPressed;
+
+    public LongPressButton()
+    {
+        Padding = 0;
+        BackgroundColor = Color.Transparent;
+    }
+
+    public void TriggerLongPress()
+    {
+        LongPressed?.Invoke(this, EventArgs.Empty);
+    }
+}

Billing.Shared/UI/Definition.cs

@@ -0,0 +1,9 @@
+namespace Billing.UI;
+
+public static partial class Definition
+{
+    public static partial string GetCascadiaRegularFontFamily();
+    public static partial string GetCascadiaBoldFontFamily();
+    public static partial string GetRobotoCondensedRegularFontFamily();
+    public static partial string GetRobotoCondensedBoldFontFamily();
+}

Billing.Shared/Views/AccountPage.xaml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ui:BillingPage xmlns="http://xamarin.com/schemas/2014/forms"
+                xmlns:r="clr-namespace:Billing.Languages"
+                xmlns:ui="clr-namespace:Billing.UI"
+                xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+                x:Class="Billing.Views.AccountPage"
+                Title="{r:Text Accounts}">
+    <StackLayout>
+        <Label Text="Welcome to Account Page!"
+               VerticalOptions="CenterAndExpand" 
+               HorizontalOptions="CenterAndExpand" />
+    </StackLayout>
+</ui:BillingPage>

Billing.Shared/Views/AccountPage.xaml.cs

@@ -0,0 +1,11 @@
+using Billing.UI;
+
+namespace Billing.Views;
+
+public partial class AccountPage : BillingPage
+{
+    public AccountPage()
+    {
+        InitializeComponent();
+    }
+}

Billing.Shared/Views/AddBillPage.xaml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ui:BillingPage xmlns="http://xamarin.com/schemas/2014/forms"
+                xmlns:ui="clr-namespace:Billing.UI"
+                xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+                x:Class="Billing.Views.AddBillPage"
+                x:DataType="v:AddBillPage"
+                Title="Add Billing">
+
+    <StackLayout>
+        <Label Text="Add a billing here..."
+                VerticalOptions="CenterAndExpand" 
+                HorizontalOptions="CenterAndExpand" />
+    </StackLayout>
+</ui:BillingPage>

Billing.Shared/Views/AddBillPage.xaml.cs

@@ -0,0 +1,11 @@
+using Billing.UI;
+
+namespace Billing.Views;
+
+public partial class AddBillPage : BillingPage
+{
+    public AddBillPage()
+    {
+        InitializeComponent();
+    }
+}

Billing.Shared/Views/BillPage.xaml

@@ -0,0 +1,56 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ui:BillingPage xmlns="http://xamarin.com/schemas/2014/forms"
+                xmlns:r="clr-namespace:Billing.Languages"
+                xmlns:ui="clr-namespace:Billing.UI"
+                xmlns:v="clr-namespace:Billing.Views"
+                xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+                x:Class="Billing.Views.BillPage"
+                x:DataType="v:BillPage"
+                x:Name="billPage"
+                BindingContext="{x:Reference billPage}"
+                Title="{r:Text Bills}">
+
+    <ContentPage.Resources>
+        <ui:TitleDateConverter x:Key="titleDateConverter"/>
+    </ContentPage.Resources>
+
+    <Shell.TitleView>
+        <Grid ColumnSpacing="16" ColumnDefinitions="20,*,20">
+            <ui:TintImage Source="calendar.png" WidthRequest="20" HeightRequest="20" VerticalOptions="Center"/>
+            <ui:LongPressButton Grid.Column="1" Text="{Binding SelectedDate, Converter={StaticResource titleDateConverter}}"
+                                TextColor="{DynamicResource PrimaryColor}"
+                                HorizontalOptions="{OnPlatform iOS=Center, Android=Start}"
+                                FontFamily="{DynamicResource RobotoCondensedFontBold}"
+                                FontAttributes="Bold" FontSize="20" VerticalOptions="Center"
+                                LongPressed="OnTitleDateLongPressed"/>
+        </Grid>
+    </Shell.TitleView>
+
+    <Grid RowDefinitions="Auto,*">
+        <ui:BillingDate x:Name="billingDate" SelectedDate="{Binding SelectedDate}" DateSelected="OnDateSelected"/>
+        <ScrollView Grid.Row="1">
+            <Grid Padding="8" ColumnSpacing="8" ColumnDefinitions="Auto, *, Auto"
+                  BackgroundColor="{DynamicResource PromptBackgroundColor}"
+                  VerticalOptions="Start">
+                <ui:TintImage Source="bars.png" WidthRequest="23" HeightRequest="23"/>
+                <Label Grid.Column="1" Text="{r:Text NoRecords}" TextColor="{DynamicResource TextColor}"
+                       VerticalOptions="Center"/>
+                <StackLayout Grid.Column="2" Orientation="Horizontal" Spacing="6">
+                    <StackLayout.GestureRecognizers>
+                        <TapGestureRecognizer Command="{Binding AddBilling}"/>
+                    </StackLayout.GestureRecognizers>
+                    <Label Text="{r:Text Memo}" TextColor="{DynamicResource PrimaryColor}"
+                           VerticalOptions="Center"/>
+                    <!--<Label Style="{DynamicResource IconLightStyle}"
+                           Text="{x:Static local:Definition.IconRight}"
+                           TextColor="{DynamicResource TabBarUnselectedColor}"/>-->
+                    <ui:TintImage Source="right.png" WidthRequest="24" HeightRequest="24"/>
+                </StackLayout>
+            </Grid>
+        </ScrollView>
+        <!--<ui:CircleButton Grid.Row="1" VerticalOptions="End" HorizontalOptions="End"
+                         Margin="20" Padding="0"
+                         BackgroundColor="{DynamicResource PrimaryColor}"
+                         ImageSource="plus.png" HeightRequest="24" WidthRequest="24"/>-->
+    </Grid>
+</ui:BillingPage>

Billing.Shared/Views/BillPage.xaml.cs

@@ -0,0 +1,44 @@
+using Billing.UI;
+using System;
+using Xamarin.Forms;
+
+namespace Billing.Views;
+
+public partial class BillPage : BillingPage
+{
+    private static readonly BindableProperty SelectedDateProperty = BindableProperty.Create(nameof(SelectedDate), typeof(DateTime), typeof(BillPage));
+
+    public DateTime SelectedDate
+    {
+        get => (DateTime)GetValue(SelectedDateProperty);
+        set => SetValue(SelectedDateProperty, value);
+    }
+
+    public Command AddBilling { get; }
+
+    public BillPage()
+    {
+        AddBilling = new Command(OnAddBilling);
+
+        InitializeComponent();
+
+        billingDate.SetDateTime(DateTime.Now);
+    }
+
+    private void OnDateSelected(object sender, DateEventArgs e)
+    {
+        SelectedDate = e.Date;
+
+        // TODO: while selecting date
+    }
+
+    private void OnTitleDateLongPressed(object sender, EventArgs e)
+    {
+        billingDate.SetDateTime(DateTime.Now);
+    }
+
+    private async void OnAddBilling()
+    {
+        await Navigation.PushAsync(new AddBillPage());
+    }
+}

Billing.Shared/Views/SettingPage.xaml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ui:BillingPage xmlns="http://xamarin.com/schemas/2014/forms"
+                xmlns:r="clr-namespace:Billing.Languages"
+                xmlns:ui="clr-namespace:Billing.UI"
+                xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+                x:Class="Billing.Views.SettingPage"
+                Title="{r:Text Settings}">
+    <StackLayout>
+        <Label Text="Welcome to Settings Page!"
+               VerticalOptions="CenterAndExpand" 
+               HorizontalOptions="CenterAndExpand" />
+    </StackLayout>
+</ui:BillingPage>

Billing.Shared/Views/SettingPage.xaml.cs

@@ -0,0 +1,11 @@
+using Billing.UI;
+
+namespace Billing.Views;
+
+public partial class SettingPage : BillingPage
+{
+    public SettingPage()
+    {
+        InitializeComponent();
+    }
+}