switch to sqlite

Billing.Shared/App.cs

@@ -27,25 +27,21 @@ namespace Billing
             InitResources();
 
             MainPage = new MainShell();
-            Shell.Current.GoToAsync("//Settings");
+            Shell.Current.GoToAsync("//Splash");
         }
 
-        public static void WriteAccounts() => StoreHelper.WriteAccounts(accounts);
-
-        public static void WriteBills() => StoreHelper.WriteBills(bills);
-
-        public static void WriteCategories() => StoreHelper.WriteCategories(categories);
-
         protected override void OnStart()
         {
             Helper.Debug($"personal folder: {StoreHelper.PersonalFolder}");
             Helper.Debug($"cache folder: {StoreHelper.CacheFolder}");
+        }
 
-            accounts = StoreHelper.GetAccounts();
+        internal static async Task InitilalizeData()
-            categories = StoreHelper.GetCategories();
+        {
-            bills = StoreHelper.GetBills();
+            await Task.WhenAll(
-
+                Task.Run(async () => accounts = await StoreHelper.GetAccountsAsync()),
-            Shell.Current.GoToAsync("//Bills");
+                Task.Run(async () => categories = await StoreHelper.GetCategoriesAsync()),
+                Task.Run(async () => bills = await StoreHelper.GetBillsAsync()));
         }
 
         protected override void OnResume()

Billing.Shared/Billing.Shared.projitems

@@ -11,6 +11,10 @@
   <ItemGroup>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Languages\en.xml" />
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Languages\zh-CN.xml" />
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)SplashPage.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
   </ItemGroup>
   <ItemGroup>
     <Compile Include="$(MSBuildThisFileDirectory)App.cs" />
@@ -21,7 +25,6 @@
     <Compile Include="$(MSBuildThisFileDirectory)MainShell.xaml.cs">
       <DependentUpon>MainShell.xaml</DependentUpon>
     </Compile>
-    <Compile Include="$(MSBuildThisFileDirectory)Models\BaseModel.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Models\Category.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Models\Account.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Themes\BaseTheme.cs" />
@@ -78,6 +81,10 @@
     <Compile Include="$(MSBuildThisFileDirectory)Store\StoreHelper.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Models\Bill.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)UI\SegmentedControl.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Models\IIdItem.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)SplashPage.xaml.cs">
+      <DependentUpon>SplashPage.xaml</DependentUpon>
+    </Compile>
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)MainShell.xaml">

Billing.Shared/Helper.cs

@@ -1,8 +1,11 @@
 using Billing.Models;
+using Billing.UI;
 using Billing.Views;
 using System;
 using System.Globalization;
 using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
 using Xamarin.Essentials;
 using Xamarin.Forms;
 
@@ -82,7 +85,7 @@ namespace Billing
         {
             return new UIBill(b)
             {
-                Icon = App.Categories.FirstOrDefault(c => c.Id == b.CategoryId)?.Icon ?? BaseModel.ICON_DEFAULT,
+                Icon = App.Categories.FirstOrDefault(c => c.Id == b.CategoryId)?.Icon ?? Definition.DefaultIcon,
                 Name = b.Name,
                 DateCreation = b.CreateTime,
                 Amount = b.Amount,
@@ -130,4 +133,24 @@ namespace Billing
 
         public delegate void PropertyValueChanged<TResult, TOwner>(TOwner obj, TResult old, TResult @new);
     }
+
+    internal class AsyncLazy<T>
+    {
+        private readonly Lazy<Task<T>> instance;
+
+        public AsyncLazy(Func<T> factory)
+        {
+            instance = new Lazy<Task<T>>(() => Task.Run(factory));
+        }
+
+        public AsyncLazy(Func<Task<T>> factory)
+        {
+            instance = new Lazy<Task<T>>(() => Task.Run(factory));
+        }
+
+        public TaskAwaiter<T> GetAwaiter()
+        {
+            return instance.Value.GetAwaiter();
+        }
+    }
 }

Billing.Shared/MainShell.xaml

@@ -1,6 +1,7 @@
 <?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:local="clr-namespace:Billing"
        xmlns:v="clr-namespace:Billing.Views"
        xmlns:r="clr-namespace:Billing.Languages"
        x:Class="Billing.MainShell"
@@ -16,4 +17,8 @@
         <ShellContent ContentTemplate="{DataTemplate v:SettingPage}" Route="Settings" Title="{r:Text Settings}" Icon="settings.png"/>
     </TabBar>
 
+    <Tab>
+        <ShellContent ContentTemplate="{DataTemplate local:SplashPage}" Route="Splash"/>
+    </Tab>
+
 </Shell>

Billing.Shared/Models/Account.cs

@@ -1,9 +1,12 @@
-using System.Xml.Linq;
+using SQLite;
 
 namespace Billing.Models
 {
-    public class Account : BaseModel
+    public class Account : IIdItem
     {
+        private const string ICON_DEFAULT = "ic_default";
+
+        [PrimaryKey, AutoIncrement]
         public int Id { get; set; }
         public string Icon { get; set; } = ICON_DEFAULT;
         public AccountCategory Category { get; set; }
@@ -11,28 +14,6 @@ namespace Billing.Models
         public decimal Initial { get; set; }
         public decimal Balance { get; set; }
         public string Memo { get; set; }
-
-        public override void OnXmlDeserialize(XElement node)
-        {
-            Id = Read(node, nameof(Id), 0);
-            Icon = Read(node, nameof(Icon), ICON_DEFAULT);
-            Category = (AccountCategory)Read(node, nameof(Category), 0);
-            Name = Read(node, nameof(Name), string.Empty);
-            Initial = Read(node, nameof(Initial), 0m);
-            Balance = Read(node, nameof(Balance), 0m);
-            Memo = Read(node, nameof(Memo), null);
-        }
-
-        public override void OnXmlSerialize(XElement node)
-        {
-            Write(node, nameof(Id), Id);
-            Write(node, nameof(Icon), Icon);
-            Write(node, nameof(Category), (int)Category);
-            Write(node, nameof(Name), Name);
-            Write(node, nameof(Initial), Initial);
-            Write(node, nameof(Balance), Balance);
-            Write(node, nameof(Memo), Memo);
-        }
     }
 
     public enum AccountCategory

Billing.Shared/Models/BaseModel.cs

@@ -1,186 +0,0 @@
-using System;
-using System.Globalization;
-using System.IO;
-using System.Linq;
-using System.Text;
-using System.Xml.Linq;
-
-namespace Billing.Models
-{
-    public interface IModel
-    {
-        void OnXmlSerialize(XElement node);
-
-        void OnXmlDeserialize(XElement node);
-    }
-
-    public abstract class BaseModel : IModel, IDisposable
-    {
-        public const string ICON_DEFAULT = "ic_default";
-
-        private bool disposed = false;
-
-        public static T ParseXml<T>(string xml) where T : BaseModel, new()
-        {
-            XDocument doc = XDocument.Parse(xml);
-            T model = new();
-            model.OnXmlDeserialize(doc.Root);
-            return model;
-        }
-
-        protected static string ToString(IFormattable v) => v.ToString(null, CultureInfo.InvariantCulture);
-        protected static double ParseDouble(string s) => double.Parse(s, CultureInfo.InvariantCulture);
-        protected static decimal ParseDecimal(string s) => decimal.Parse(s, CultureInfo.InvariantCulture);
-        protected static int ParseInt(string s) => int.Parse(s, CultureInfo.InvariantCulture);
-        protected static long ParseLong(string s) => long.Parse(s, CultureInfo.InvariantCulture);
-
-        protected static bool IsTrue(string s) =>
-            string.Equals(s, "true", StringComparison.OrdinalIgnoreCase) ||
-            string.Equals(s, "yes", StringComparison.OrdinalIgnoreCase) ||
-            s == "1";
-
-        #region Private Methods
-
-        private static XElement WriteString(XElement parent, string name, string val, Action<XElement> action = null)
-        {
-            XElement ele;
-            if (val == null)
-            {
-                ele = new XElement(name);
-            }
-            else
-            {
-                ele = new XElement(name, val);
-            }
-            action?.Invoke(ele);
-            parent.Add(ele);
-            return ele;
-        }
-
-        private static T ReadSubnode<T>(XElement node, string subname, Func<XElement, T> func)
-        {
-            var ele = node.Elements().FirstOrDefault(e => string.Equals(e.Name.ToString(), subname, StringComparison.OrdinalIgnoreCase));
-            return func(ele);
-        }
-
-        private static T ReadObject<T>(XElement node) where T : IModel, new()
-        {
-            if (IsTrue(node.Attribute("null")?.Value))
-            {
-                return default;
-            }
-            T value = new();
-            value.OnXmlDeserialize(node);
-            return value;
-        }
-
-        private static T[] ReadArray<T>(XElement node) where T : IModel, new()
-        {
-            if (IsTrue(node.Attribute("null")?.Value))
-            {
-                return default;
-            }
-            int count = ParseInt(node.Attribute("count").Value);
-            T[] array = new T[count];
-            foreach (XElement ele in node.Elements("item"))
-            {
-                int index = ParseInt(ele.Attribute("index").Value);
-                array[index] = ReadObject<T>(ele);
-            }
-            return array;
-        }
-
-        #endregion
-
-        #region Read/Write Helper
-
-        protected static XElement Write(XElement parent, string name, string val) => WriteString(parent, name, val);
-        protected static XElement Write(XElement parent, string name, DateTime date) => WriteString(parent, name, ToString(date.Ticks));
-        protected static XElement Write<T>(XElement parent, string name, T value) where T : IFormattable => WriteString(parent, name, ToString(value));
-        protected static XElement WriteObject<T>(XElement parent, string name, T value) where T : IModel => WriteString(parent, name, null,
-            action: ele =>
-            {
-                if (value == null)
-                {
-                    ele.Add(new XAttribute("null", 1));
-                }
-                else
-                {
-                    value.OnXmlSerialize(ele);
-                }
-            });
-        protected static XElement WriteArray<T>(XElement parent, string name, T[] value) where T : IModel => WriteString(parent, name, null,
-            action: ele =>
-            {
-                if (value == null)
-                {
-                    ele.Add(new XAttribute("null", 1));
-                }
-                else
-                {
-                    ele.Add(new XAttribute("count", value.Length));
-                    for (var i = 0; i < value.Length; i++)
-                    {
-                        XElement item = WriteObject(ele, "item", value[i]);
-                        item.Add(new XAttribute("index", i));
-                    }
-                }
-            });
-
-        protected static string Read(XElement node, string subname, string def) => ReadSubnode(node, subname, e => e?.Value ?? def);
-        protected static int Read(XElement node, string subname, int def) => ReadSubnode(node, subname, e => e == null ? def : ParseInt(e.Value));
-        protected static long Read(XElement node, string subname, long def) => ReadSubnode(node, subname, e => e == null ? def : ParseLong(e.Value));
-        protected static double Read(XElement node, string subname, double def) => ReadSubnode(node, subname, e => e == null ? def : ParseDouble(e.Value));
-        protected static decimal Read(XElement node, string subname, decimal def) => ReadSubnode(node, subname, e => e == null ? def : ParseDecimal(e.Value));
-        protected static DateTime Read(XElement node, string subname, DateTime def) => ReadSubnode(node, subname, e => e == null ? def : new DateTime(ParseLong(e.Value)));
-        protected static T ReadObject<T>(XElement node, string subname, T def = default) where T : IModel, new() => ReadSubnode(node, subname, e => e == null ? def : ReadObject<T>(e));
-        protected static T[] ReadArray<T>(XElement node, string subname, T[] def = null) where T : IModel, new() => ReadSubnode(node, subname, e => e == null ? def : ReadArray<T>(e));
-
-        #endregion
-
-        public XDocument ToXml()
-        {
-            XDocument xdoc = new(new XDeclaration("1.0", "utf-8", "yes"), new XElement("root"));
-            ToXml(xdoc.Root);
-            return xdoc;
-        }
-
-        public void ToXml(XElement node)
-        {
-            OnXmlSerialize(node);
-        }
-
-        public void SaveToStream(Stream stream)
-        {
-            ToXml().Save(stream, SaveOptions.DisableFormatting);
-        }
-
-        public abstract void OnXmlSerialize(XElement node);
-        public abstract void OnXmlDeserialize(XElement node);
-
-
-        public override string ToString()
-        {
-            using MemoryStream ms = new();
-            //using StreamWriter writer = new(ms, Encoding.UTF8);
-            //XDocument xdoc = ToXml();
-            //xdoc.Save(writer, SaveOptions.DisableFormatting);
-            //writer.Flush();
-            SaveToStream(ms);
-            ms.Seek(0, SeekOrigin.Begin);
-            using StreamReader reader = new(ms, Encoding.UTF8);
-            return reader.ReadToEnd();
-        }
-
-        protected virtual void Dispose(bool dispose) { }
-
-        public void Dispose()
-        {
-            if (!disposed)
-            {
-                Dispose(true);
-                disposed = true;
-            }
-        }
-    }
-}

Billing.Shared/Models/Bill.cs

@@ -1,10 +1,11 @@
 using System;
-using System.Xml.Linq;
+using SQLite;
 
 namespace Billing.Models
 {
-    public class Bill : BaseModel
+    public class Bill : IIdItem
     {
+        [PrimaryKey, AutoIncrement]
         public int Id { get; set; }
         public decimal Amount { get; set; }
         public string Name { get; set; }
@@ -13,29 +14,5 @@ namespace Billing.Models
         public string Store { get; set; }
         public DateTime CreateTime { get; set; }
         public string Note { get; set; }
-
-        public override void OnXmlDeserialize(XElement node)
-        {
-            Id = Read(node, nameof(Id), 0);
-            Amount = Read(node, nameof(Amount), 0m);
-            Name = Read(node, nameof(Name), string.Empty);
-            CategoryId = Read(node, nameof(CategoryId), -1);
-            WalletId = Read(node, nameof(WalletId), -1);
-            Store = Read(node, nameof(Store), string.Empty);
-            CreateTime = Read(node, nameof(CreateTime), default(DateTime));
-            Note = Read(node, nameof(Note), string.Empty);
-        }
-
-        public override void OnXmlSerialize(XElement node)
-        {
-            Write(node, nameof(Id), Id);
-            Write(node, nameof(Amount), Amount);
-            Write(node, nameof(Name), Name);
-            Write(node, nameof(CategoryId), CategoryId);
-            Write(node, nameof(WalletId), WalletId);
-            Write(node, nameof(Store), Store);
-            Write(node, nameof(CreateTime), CreateTime);
-            Write(node, nameof(Note), Note);
-        }
     }
 }

Billing.Shared/Models/Category.cs

@@ -1,50 +1,19 @@
-using Xamarin.Forms;
+using SQLite;
-using System.Xml.Linq;
 
 namespace Billing.Models
 {
-    public class Category : BaseModel
+    public class Category : IIdItem
     {
+        private const string ICON_DEFAULT = "ic_default";
+        private const long TRANSPARENT_COLOR = 0x00ffffffL;
+
+        [PrimaryKey, AutoIncrement]
         public int Id { get; set; }
         public CategoryType Type { get; set; }
         public string Icon { get; set; } = ICON_DEFAULT;
         public string Name { get; set; }
-        public Color TintColor { get; set; } = Color.Transparent;
+        public long TintColor { get; set; } = TRANSPARENT_COLOR;
         public int? ParentId { get; set; }
-
-        public override void OnXmlDeserialize(XElement node)
-        {
-            Id = Read(node, nameof(Id), 0);
-            Type = (CategoryType)Read(node, nameof(Type), 0);
-            Icon = Read(node, nameof(Icon), ICON_DEFAULT);
-            Name = Read(node, nameof(Name), string.Empty);
-            var color = Read(node, nameof(TintColor), string.Empty);
-            if (!string.IsNullOrEmpty(color))
-            {
-                TintColor = Color.FromHex(color);
-            }
-            var parentId = Read(node, nameof(ParentId), -1);
-            if (parentId >= 0)
-            {
-                ParentId = parentId;
-            }
-        }
-
-        public override void OnXmlSerialize(XElement node)
-        {
-            Write(node, nameof(Id), Id);
-            Write(node, nameof(Type), (int)Type);
-            Write(node, nameof(Icon), Icon);
-            Write(node, nameof(Name), Name);
-            if (TintColor != Color.Transparent)
-            {
-                Write(node, nameof(TintColor), TintColor.ToHex());
-            }
-            if (ParentId != null)
-            {
-                Write(node, nameof(ParentId), ParentId.Value);
-            }
-        }
     }
 
     public enum CategoryType

Billing.Shared/Models/IIdItem.cs

@@ -0,0 +1,7 @@
+namespace Billing.Models
+{
+    public interface IIdItem
+    {
+        public int Id { get; }
+    }
+}

Billing.Shared/SplashPage.xaml

@@ -0,0 +1,9 @@
+<?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.SplashPage"
+                Shell.NavBarIsVisible="False"
+                Shell.TabBarIsVisible="False">
+    <!--<Label Text="Loading..." HorizontalOptions="Center" VerticalOptions="Center"/>-->
+</ui:BillingPage>

Billing.Shared/SplashPage.xaml.cs

@@ -0,0 +1,20 @@
+using Billing.UI;
+using Xamarin.Forms;
+
+namespace Billing
+{
+    public partial class SplashPage : BillingPage
+    {
+        public SplashPage()
+        {
+            InitializeComponent();
+        }
+
+        public override async void OnLoaded()
+        {
+            await App.InitilalizeData();
+
+            await Shell.Current.GoToAsync("//Bills");
+        }
+    }
+}

Billing.Shared/Store/StoreHelper.cs

@@ -1,9 +1,10 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Threading.Tasks;
 using Billing.Models;
-using Billing.UI;
+using SQLite;
 using Xamarin.Essentials;
 using Resource = Billing.Languages.Resource;
 
@@ -14,50 +15,20 @@ namespace Billing.Store
         public static readonly string PersonalFolder = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
         public static readonly string CacheFolder = FileSystem.CacheDirectory;
 
-        private const string accountFile = "accounts.xml";
+        #region Sqlite3
-        private const string billFile = "bills.xml";
+        private const string dbfile = "data.db3";
-        private const string categoryFile = "categories.xml";
+        private static SQLiteAsyncConnection database;
+        #endregion
 
-        private static StoreHelper instance;
+        private static readonly AsyncLazy<StoreHelper> Instance = new(async () =>
-        private static StoreHelper Instance => instance ??= new StoreHelper();
-
-        public static List<Account> GetAccounts() => Instance.GetAccountsInternal();
-        public static void WriteAccounts(IEnumerable<Account> accounts) => Instance.WriteAccountsInternal(accounts);
-        public static List<Bill> GetBills() => Instance.GetBillsInternal();
-        public static void WriteBills(IEnumerable<Bill> bills) => Instance.WriteBillsInternal(bills);
-        public static List<Category> GetCategories() => Instance.GetCategoriesInternal();
-        public static void WriteCategories(IEnumerable<Category> categories) => Instance.WriteCategoriesInternal(categories);
-
-        private StoreHelper() { }
-
-        private List<Account> GetAccountsInternal()
         {
-            return GetList<Account>(Path.Combine(PersonalFolder, accountFile));
+            var instance = new StoreHelper();
-        }
+            await database.CreateTablesAsync<Category, Account, Bill>();
-
+            var count = await database.ExecuteScalarAsync<int>("SELECT COUNT(Id) FROM [Category]");
-        private void WriteAccountsInternal(IEnumerable<Account> accounts)
+            if (count <= 0)
             {
-            var filename = Path.Combine(PersonalFolder, accountFile);
+                // init categories
-            WriteList(filename, accounts);
+                await database.InsertAllAsync(new List<Category>
-        }
-
-        private List<Bill> GetBillsInternal()
-        {
-            return GetList<Bill>(Path.Combine(PersonalFolder, billFile));
-        }
-
-        private void WriteBillsInternal(IEnumerable<Bill> bills)
-        {
-            var filename = Path.Combine(PersonalFolder, billFile);
-            WriteList(filename, bills);
-        }
-
-        private List<Category> GetCategoriesInternal()
-        {
-            var list = GetList<Category>(Path.Combine(PersonalFolder, categoryFile));
-            if (list == null || list.Count == 0)
-            {
-                list = new List<Category>
                 {
                     // sample categories
                     new() { Id = 1, Name = Resource.Clothing, Icon = "clothes" },
@@ -89,55 +60,147 @@ namespace Billing.Store
                     new() { Id = 113, ParentId = 6, Name = Resource.Party, Icon = "party" },
                     new() { Id = 200, ParentId = 10, Type = CategoryType.Income, Name = Resource.Salary, Icon = "#brand#buffer" },
                     new() { Id = 201, ParentId = 10, Type = CategoryType.Income, Name = Resource.Bonus, Icon = "dollar" },
-                };
+                });
-                Task.Run(() => WriteCategoriesInternal(list));
             }
-            return list;
+            return instance;
+        });
+
+        public static async Task<List<Account>> GetAccountsAsync()
+        {
+            var instance = await Instance;
+            return await instance.GetListAsync<Account>();
+        }
+        public static async Task<int> SaveAccountItemAsync(Account account)
+        {
+            var instance = await Instance;
+            return await instance.SaveItemAsync(account);
+        }
+        public static async Task<int> DeleteAccountItemAsync(Account account)
+        {
+            var instance = await Instance;
+            return await instance.DeleteItemAsync(account);
         }
 
-        private void WriteCategoriesInternal(IEnumerable<Category> categories)
+        public static async Task<List<Bill>> GetBillsAsync()
         {
-            var filename = Path.Combine(PersonalFolder, categoryFile);
+            var instance = await Instance;
-            WriteList(filename, categories);
+            return await instance.GetListAsync<Bill>();
+        }
+        public static async Task<int> SaveBillItemAsync(Bill bill)
+        {
+            var instance = await Instance;
+            return await instance.SaveItemAsync(bill);
+        }
+        public static async Task<int> DeleteBillItemAsync(Bill bill)
+        {
+            var instance = await Instance;
+            return await instance.DeleteItemAsync(bill);
+        }
+
+        public static async Task<List<Category>> GetCategoriesAsync()
+        {
+            var instance = await Instance;
+            return await instance.GetListAsync<Category>();
+        }
+        public static async Task<int> SaveCategoryItemAsync(Category category)
+        {
+            var instance = await Instance;
+            return await instance.SaveItemAsync(category);
+        }
+        public static async Task<int> DeleteCategoryItemAsync(Category category)
+        {
+            var instance = await Instance;
+            return await instance.DeleteItemAsync(category);
+        }
+
+        private StoreHelper()
+        {
+            database = new SQLiteAsyncConnection(Path.Combine(PersonalFolder, dbfile),
+                SQLiteOpenFlags.ReadWrite |
+                SQLiteOpenFlags.Create |
+                SQLiteOpenFlags.SharedCache);
+        }
+
+        public Task<List<T>> GetListAsync<T>(string query, params object[] args) where T : new()
+        {
+            try
+            {
+                return database.QueryAsync<T>(query, args);
+            }
+            catch (Exception ex)
+            {
+                Helper.Error("db.read", $"failed to read db, query: {string.Format(query, args)}, error: {ex.Message}");
+            }
+            return default;
+        }
+
+        public Task<T> GetItemAsync<T>(int id) where T : IIdItem, new()
+        {
+            try
+            {
+                var source = new TaskCompletionSource<T>();
+                Task.Run(async () =>
+                {
+                    var list = await database.QueryAsync<T>($"SELECT * FROM [{typeof(T).Name}] WHERE [Id] = ?", id);
+                    source.SetResult(list.FirstOrDefault());
+                });
+                return source.Task;
+            }
+            catch (Exception ex)
+            {
+                Helper.Error("db.read", $"failed to get item, table: {typeof(T)}, id: {id}, error: {ex.Message}");
+            }
+            return default;
         }
 
         #region Helper
 
-        private void WriteList<T>(string filename, IEnumerable<T> list) where T : IModel, new()
+        private Task<List<T>> GetListAsync<T>() where T : new()
-        {
-            if (list == null)
-            {
-                return;
-            }
-            try
-            {
-                using var stream = File.Open(filename, FileMode.Create);
-                list.ToStream(stream);
-            }
-            catch (Exception ex)
-            {
-                Helper.Error("file.write", $"failed to write file: {filename}, error: {ex.Message}");
-            }
-        }
-
-        private List<T> GetList<T>(string file) where T : IModel, new()
         {
             try
             {
-                if (File.Exists(file))
+                return database.Table<T>().ToListAsync();
-                {
-                    using var stream = File.OpenRead(file);
-                    var list = ModelExtensionHelper.FromStream<T>(stream);
-                    return list;
-                }
             }
             catch (Exception ex)
             {
-                Helper.Error("file.read", $"failed to read file: {file}, error: {ex.Message}");
+                Helper.Error("db.read", $"failed to read db, error: {ex.Message}");
             }
             return default;
         }
 
+        private Task<int> SaveItemAsync<T>(T item) where T : IIdItem
+        {
+            try
+            {
+                if (item.Id < 0)
+                {
+                    return database.InsertAsync(item);
+                }
+                else
+                {
+                    return database.UpdateAsync(item);
+                }
+            }
+            catch (Exception ex)
+            {
+                Helper.Error("db.write", $"failed to insert/update item, table: {typeof(T)}, id: {item.Id}, item: {item}, error: {ex.Message}");
+            }
+            return Task.FromResult(-1);
+        }
+
+        private Task<int> DeleteItemAsync<T>(T item) where T : IIdItem
+        {
+            try
+            {
+                return database.DeleteAsync(item);
+            }
+            catch (Exception ex)
+            {
+                Helper.Error("db.delete", $"failed to delete item, table: {typeof(T)}, id: {item.Id}, item: {item}, error: {ex.Message}");
+            }
+            return Task.FromResult(-1);
+        }
+
         #endregion
     }
 }

Billing.Shared/UI/Converters.cs

@@ -205,7 +205,7 @@ namespace Billing.UI
                     {
                         if (!int.TryParse(key, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out int i))
                         {
-                            return ImageSource.FromFile(BaseModel.ICON_DEFAULT);
+                            return ImageSource.FromFile(Definition.DefaultIcon);
                         }
                         glyph = char.ConvertFromUtf32(i);
                     }

Billing.Shared/UI/Definition.cs

@@ -1,17 +1,15 @@
 using System;
-using System.Collections.Generic;
-using System.IO;
 using System.Threading.Tasks;
-using System.Xml.Linq;
 using Billing.Languages;
-using Billing.Models;
 using Xamarin.Forms;
 
 namespace Billing.UI
 {
     public static partial class Definition
     {
-        public static string PrimaryColorKey = "PrimaryColor";
+        public const string PrimaryColorKey = "PrimaryColor";
+        public const string DefaultIcon = "ic_default";
+
         public static partial (string main, long build) GetVersion();
         public static partial string GetRegularFontFamily();
         public static partial string GetSemiBoldFontFamily();
@@ -98,50 +96,33 @@ namespace Billing.UI
             // add 23:59:59.999...
             return date.AddTicks(863999999999);
         }
+
+        public static bool IsTransparent(this long color)
+        {
+            return (color & 0xff000000L) == 0x00000000L;
         }
 
-    public static class ModelExtensionHelper
+        public static Color ToColor(this long color)
         {
-        public static List<T> FromStream<T>(Stream stream) where T : IModel, new()
+            ulong c = (ulong)color;
-        {
+            int r = (int)(c & 0xff);
-            XDocument doc = XDocument.Load(stream);
+            c >>= 8;
-            var root = doc.Root;
+            int g = (int)(c & 0xff);
-            var list = new List<T>();
+            c >>= 8;
-            foreach (XElement ele in root.Elements("item"))
+            int b = (int)(c & 0xff);
-            {
+            c >>= 8;
-                if (ele.Attribute("null")?.Value == "1")
+            int a = (int)(c & 0xff);
-                {
+            return Color.FromRgba(r, g, b, a);
-                    list.Add(default);
-                }
-                else
-                {
-                    T value = new();
-                    value.OnXmlDeserialize(ele);
-                    list.Add(value);
-                }
-            }
-            return list;
         }
 
-        public static void ToStream<T>(this IEnumerable<T> list, Stream stream) where T : IModel
+        public static long ToLong(this Color color)
         {
-            XElement root = new("root");
+            long l =
-            foreach (var t in list)
+                (uint)(color.A * 255) << 24 |
-            {
+                (uint)(color.B * 255) << 16 |
-                XElement item = new("item");
+                (uint)(color.G * 255) << 8 |
-                if (t == null)
+                (uint)(color.R * 255);
-                {
+            return l;
-                    item.Add(new XAttribute("null", 1));
-                }
-                else
-                {
-                    t.OnXmlSerialize(item);
-                }
-                root.Add(item);
-            }
-
-            XDocument doc = new(new XDeclaration("1.0", "utf-8", "yes"), root);
-            doc.Save(stream, SaveOptions.DisableFormatting);
         }
     }
 

Billing.Shared/Views/AccountPage.xaml.cs

@@ -1,8 +1,8 @@
 using System.Collections.Generic;
 using System.Linq;
-using System.Threading.Tasks;
 using Billing.Languages;
 using Billing.Models;
+using Billing.Store;
 using Billing.UI;
 using Xamarin.Forms;
 
@@ -120,25 +120,27 @@ namespace Billing.Views
                         if (group == null)
                         {
                             Helper.Error("account.delete", "unexpected deleting account, cannot find the current category");
-                            return;
                         }
+                        else
+                        {
                             group.Remove(account);
                             if (group.Count == 0)
                             {
                                 accounts.Remove(group);
                             }
+                        }
                         RefreshBalance();
                         groupLayout.Refresh(accounts);
 
                         RankPage.Instance?.SetNeedRefresh();
 
-                        _ = Task.Run(App.WriteAccounts);
+                        await StoreHelper.DeleteAccountItemAsync(account);
                     }
                 }
             }
         }
 
-        private void AccountChecked(object sender, AccountEventArgs e)
+        private async void AccountChecked(object sender, AccountEventArgs e)
         {
             var add = e.Account.Id < 0;
             if (add)
@@ -151,7 +153,7 @@ namespace Billing.Views
 
             RankPage.Instance?.SetNeedRefresh();
 
-            Task.Run(App.WriteAccounts);
+            await StoreHelper.SaveAccountItemAsync(e.Account);
         }
     }
 

Billing.Shared/Views/AddAccountPage.xaml.cs

@@ -59,7 +59,7 @@ namespace Billing.Views
             this.account = account;
             if (account == null)
             {
-                AccountIcon = BaseModel.ICON_DEFAULT;
+                AccountIcon = Definition.DefaultIcon;
                 Category = AccountCategory.Cash;
             }
             else

Billing.Shared/Views/AddCategoryPage.xaml.cs

@@ -56,14 +56,13 @@ namespace Billing.Views
             {
                 CategoryName = category.Name;
                 CategoryIcon = category.Icon;
-                if (category.TintColor == Color.Transparent ||
+                if (category.TintColor.IsTransparent())
-                    category.TintColor == default)
                 {
                     TintColor = BaseTheme.CurrentPrimaryColor;
                 }
                 else
                 {
-                    TintColor = category.TintColor;
+                    TintColor = category.TintColor.ToColor();
                 }
             }
             else
@@ -103,6 +102,7 @@ namespace Billing.Views
             {
                 var currentColor = BaseTheme.CurrentPrimaryColor;
                 var tintColor = TintColor;
+                var color = (tintColor == currentColor ? Color.Transparent : tintColor).ToLong();
                 var category = App.Categories.FirstOrDefault(c => c.Id == categoryId);
                 if (category == null)
                 {
@@ -111,7 +111,7 @@ namespace Billing.Views
                         Id = -1,
                         Name = CategoryName,
                         Icon = CategoryIcon,
-                        TintColor = tintColor == currentColor ? Color.Transparent : tintColor,
+                        TintColor = color,
                         ParentId = parent?.Id,
                         Type = parent?.Type ?? CategoryType.Spending
                     });
@@ -120,7 +120,7 @@ namespace Billing.Views
                 {
                     category.Name = CategoryName;
                     category.Icon = CategoryIcon;
-                    category.TintColor = tintColor == currentColor ? Color.Transparent : tintColor;
+                    category.TintColor = color;
                     CategoryChecked?.Invoke(this, category);
                 }
                 await Navigation.PopAsync();

Billing.Shared/Views/BillPage.xaml.cs

@@ -1,4 +1,5 @@
 using Billing.Models;
+using Billing.Store;
 using Billing.UI;
 using System;
 using System.Collections.Generic;
@@ -84,7 +85,7 @@ namespace Billing.Views
 
         private void UpdateBill(UIBill bill)
         {
-            bill.Icon = App.Categories.FirstOrDefault(c => c.Id == bill.Bill.CategoryId)?.Icon ?? BaseModel.ICON_DEFAULT;
+            bill.Icon = App.Categories.FirstOrDefault(c => c.Id == bill.Bill.CategoryId)?.Icon ?? Definition.DefaultIcon;
             bill.Name = bill.Bill.Name;
             bill.DateCreation = bill.Bill.CreateTime;
             bill.Amount = bill.Bill.Amount;
@@ -158,13 +159,13 @@ namespace Billing.Views
 
                         RankPage.Instance?.SetNeedRefresh();
 
-                        _ = Task.Run(App.WriteBills);
+                        await StoreHelper.DeleteBillItemAsync(bill.Bill);
                     }
                 }
             }
         }
 
-        private void OnBillChecked(object sender, Bill e)
+        private async void OnBillChecked(object sender, Bill e)
         {
             if (e.Id < 0)
             {
@@ -195,7 +196,7 @@ namespace Billing.Views
 
             RankPage.Instance?.SetNeedRefresh();
 
-            Task.Run(App.WriteBills);
+            await StoreHelper.SaveBillItemAsync(e);
         }
     }
 

Billing.Shared/Views/CategoryPage.xaml.cs

@@ -1,11 +1,11 @@
 using Billing.Languages;
 using Billing.Models;
+using Billing.Store;
 using Billing.Themes;
 using Billing.UI;
 using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
-using System.Threading.Tasks;
 using Xamarin.Forms;
 
 namespace Billing.Views
@@ -68,9 +68,9 @@ namespace Billing.Views
                 Icon = category.Icon,
                 Name = category.Name,
                 IsTopCategory = IsTopCategory,
-                TintColor = category.TintColor == Color.Transparent || category.TintColor == default ?
+                TintColor = category.TintColor.IsTransparent() ?
                     BaseTheme.CurrentPrimaryColor :
-                    category.TintColor
+                    category.TintColor.ToColor()
             };
         }
 
@@ -112,7 +112,7 @@ namespace Billing.Views
                             Categories.Remove(c);
                             groupLayout.Refresh(Categories);
                             App.Categories.Remove(c.Category);
-                            _ = Task.Run(App.WriteCategories);
+                            await StoreHelper.DeleteCategoryItemAsync(c.Category);
                         }
                     }
                 }
@@ -144,7 +144,7 @@ namespace Billing.Views
             }
         }
 
-        private void OnCategoryChecked(object sender, Category category)
+        private async void OnCategoryChecked(object sender, Category category)
         {
             if (category.Id < 0)
             {
@@ -183,16 +183,16 @@ namespace Billing.Views
             }
             groupLayout.Refresh(Categories);
 
-            Task.Run(App.WriteCategories);
+            await StoreHelper.SaveCategoryItemAsync(category);
         }
 
         private void UpdateCategory(UICategory c)
         {
             c.Name = c.Category.Name;
             c.Icon = c.Category.Icon;
-            c.TintColor = c.Category.TintColor == Color.Transparent || c.Category.TintColor == default ?
+            c.TintColor = c.Category.TintColor.IsTransparent() ?
                 BaseTheme.CurrentPrimaryColor :
-                c.Category.TintColor;
+                c.Category.TintColor.ToColor();
         }
     }
 

Billing.Shared/Views/CategorySelectPage.xaml.cs

@@ -72,7 +72,7 @@ namespace Billing.Views
                 IsChecked = c.Id == categoryId,
                 Icon = c.Icon,
                 Name = c.Name,
-                TintColor = c.TintColor == Color.Transparent || c.TintColor == default ? defaultColor : c.TintColor
+                TintColor = c.TintColor.IsTransparent() ? defaultColor : c.TintColor.ToColor()
             };
         }
 

Billing.Shared/Views/IconSelectPage.xaml.cs

@@ -1,5 +1,4 @@
-using Billing.Models;
+using Billing.UI;
-using Billing.UI;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -37,7 +36,7 @@ namespace Billing.Views
         {
             var source = new List<BillingIcon>
             {
-                new() { Icon = BaseModel.ICON_DEFAULT },
+                new() { Icon = Definition.DefaultIcon },
                 new() { Icon = "wallet" },
                 new() { Icon = "dollar" },
                 new() { Icon = "creditcard" },

Billing.Shared/Views/RankPage.xaml.cs

@@ -1,4 +1,5 @@
 using Billing.Models;
+using Billing.Store;
 using Billing.Themes;
 using Billing.UI;
 using Microcharts;
@@ -473,7 +474,7 @@ namespace Billing.Views
 
         private async void OnBillChecked(object sender, Bill e)
         {
-            await Task.Run(App.WriteBills);
+            await StoreHelper.SaveBillItemAsync(e);
             LoadData();
         }
 

Billing/Billing.Android/Billing.Android.csproj

@@ -65,12 +65,11 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="Microcharts.Forms">
+    <PackageReference Include="Microcharts.Forms" Version="0.9.5.9" />
-      <Version>0.9.5.9</Version>
-    </PackageReference>
     <PackageReference Include="SkiaSharp.Views.Forms" Version="2.80.3" />
     <PackageReference Include="Xamarin.Forms" Version="5.0.0.2337" />
     <PackageReference Include="Xamarin.Essentials" Version="1.7.1" />
+    <PackageReference Include="sqlite-net-pcl" Version="1.8.116" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Definition.cs" />

Billing/Billing.iOS/Billing.iOS.csproj

@@ -169,12 +169,11 @@
     <Reference Include="System.Numerics.Vectors" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="Microcharts.Forms">
+    <PackageReference Include="Microcharts.Forms" Version="0.9.5.9" />
-      <Version>0.9.5.9</Version>
-    </PackageReference>
     <PackageReference Include="SkiaSharp.Views.Forms" Version="2.80.3" />
     <PackageReference Include="Xamarin.Forms" Version="5.0.0.2337" />
     <PackageReference Include="Xamarin.Essentials" Version="1.7.1" />
+    <PackageReference Include="sqlite-net-pcl" Version="1.8.116" />
   </ItemGroup>
   <ItemGroup>
     <BundleResource Include="Resources\dollar.png" />

Billing/Billing.iOS/Info.plist

@@ -41,8 +41,6 @@
 		<string>OpenSans-Regular.ttf</string>
 		<string>OpenSans-SemiBold.ttf</string>
 	</array>
-	<key>UIFileSharingEnabled</key>
-	<true/>
 	<key>CFBundleVersion</key>
 	<string>9</string>
 	<key>CFBundleShortVersionString</key>