first step

Billing.Shared/Languages/Resource.cs

@@ -9,6 +9,7 @@ namespace Billing.Languages
 {
     internal class Resource
     {
+        public static string Ok => Text(nameof(Ok));
         public static string TitleDateFormat => Text(nameof(TitleDateFormat));
         public static string Cash => Text(nameof(Cash));
         public static string CreditCard => Text(nameof(CreditCard));
@@ -16,6 +17,11 @@ namespace Billing.Languages
         public static string ElecAccount => Text(nameof(ElecAccount));
         public static string AddBill => Text(nameof(AddBill));
         public static string EditBill => Text(nameof(EditBill));
+        public static string AddAccount => Text(nameof(AddAccount));
+        public static string EditAccount => Text(nameof(EditAccount));
+        public static string AccountRequired => Text(nameof(AccountRequired));
+        public static string NeedAccount => Text(nameof(NeedAccount));
+        public static string AmountRequired => Text(nameof(AmountRequired));
 
         static readonly Dictionary<string, LanguageResource> dict = new();
 

Billing.Shared/Languages/en.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <root>
+	<Ok>OK</Ok>
 	<Accounts>Accounts</Accounts>
 	<Bills>Bills</Bills>
 	<Settings>Settings</Settings>
@@ -17,8 +18,10 @@
 	<Assets>Assets</Assets>
 	<Liability>Liability</Liability>
 	<AddAccount>Add Account</AddAccount>
+	<EditAccount>Edit Account</EditAccount>
 	<AccountName>Account Name</AccountName>
 	<AccountNamePlaceholder>Please enter account name</AccountNamePlaceholder>
+	<AccountRequired>The account name is required.</AccountRequired>
 	<Icon>Icon</Icon>
 	<Category>Category</Category>
 	<Balance>Balance</Balance>
@@ -34,6 +37,11 @@
 	<IconSelector>Icon Selection</IconSelector>
 	<AddBill>Add Billing</AddBill>
 	<EditBill>Edit Billing</EditBill>
+	<Name>Name</Name>
+	<NamePlaceholder>Please enter the name</NamePlaceholder>
 	<Account>Account</Account>
 	<CreatedTime>Created Time</CreatedTime>
+	<Store>Store</Store>
+	<NeedAccount>Please create an account first.</NeedAccount>
+	<AmountRequired>Please enter the amount.</AmountRequired>
 </root>

Billing.Shared/Languages/zh-CN.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <root>
+	<Ok>确定</Ok>
 	<Accounts>账户</Accounts>
 	<Bills>账单</Bills>
 	<Settings>设置</Settings>
@@ -17,8 +18,10 @@
 	<Assets>资产</Assets>
 	<Liability>负债</Liability>
 	<AddAccount>新建账户</AddAccount>
+	<EditAccount>编辑账户</EditAccount>
 	<AccountName>账户名称</AccountName>
 	<AccountNamePlaceholder>请输入账户名称</AccountNamePlaceholder>
+	<AccountRequired>账户名称不可为空。</AccountRequired>
 	<Icon>图标</Icon>
 	<Category>种类</Category>
 	<Balance>余额</Balance>
@@ -34,6 +37,11 @@
 	<IconSelector>图标选择</IconSelector>
 	<AddBill>增加账单</AddBill>
 	<EditBill>编辑账单</EditBill>
+	<Name>名称</Name>
+	<NamePlaceholder>请输入名称</NamePlaceholder>
 	<Account>账户</Account>
 	<CreatedTime>创建时间</CreatedTime>
+	<Store>店铺</Store>
+	<NeedAccount>请先创建一个资金账户。</NeedAccount>
+	<AmountRequired>请输入金额。</AmountRequired>
 </root>

Billing.Shared/Models/Bill.cs

@@ -5,31 +5,37 @@ namespace Billing.Models
 {
     public class Bill : BaseModel
     {
+        public int Id { get; set; }
         public decimal Amount { get; set; }
         public string Name { get; set; }
         public int CategoryId { get; set; }
         public int WalletId { get; set; }
         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/Store/StoreHelper.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Threading.Tasks;
 using Billing.Models;
 using Billing.UI;
 using Xamarin.Essentials;
@@ -52,7 +53,21 @@ namespace Billing.Store
 
         private List<Category> GetCategoriesInternal()
         {
-            return GetList<Category>(Path.Combine(PersonalFolder, categoryFile));
+            var list = GetList<Category>(Path.Combine(PersonalFolder, categoryFile));
+            if (list == null || list.Count == 0)
+            {
+                list = new List<Category>
+                {
+                    // TODO: sample categories
+                    new() { Id = 0, Name = "早餐", Icon = "face" },
+                    new() { Id = 1, Name = "轻轨", Icon = "" },
+                    new() { Id = 2, Name = "公交车", Icon = "" },
+                    new() { Id = 3, Name = "出租车", Icon = "" },
+                    new() { Id = 4, Type = CategoryType.Income, Name = "投资", Icon = "#brand#btc" }
+                };
+                Task.Run(() => WriteCategoriesInternal(list));
+            }
+            return list;
         }
 
         private void WriteCategoriesInternal(IEnumerable<Category> categories)
@@ -71,7 +86,7 @@ namespace Billing.Store
             }
             try
             {
-                using var stream = File.OpenWrite(filename);
+                using var stream = File.Open(filename, FileMode.Create);
                 list.ToStream(stream);
             }
             catch (Exception ex)

Billing.Shared/Themes/Light.cs

@@ -28,7 +28,7 @@ namespace Billing.Themes
             Add(TextColor, Color.FromRgb(0x33, 0x33, 0x33));
             Add(SecondaryTextColor, Color.DimGray);
             Add(RedColor, Color.FromRgb(211, 64, 85));
-            Add(RedColor, Color.FromRgb(64, 211, 85));
+            Add(GreenColor, Color.FromRgb(64, 211, 85));
 
             Add(new Style(typeof(TabBar))
             {

Billing.Shared/UI/Definition.cs

@@ -1,7 +1,9 @@
 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;
 
@@ -77,6 +79,11 @@ namespace Billing.UI
             Grid.SetRowSpan(view, rowSpan);
             return view;
         }
+
+        public static async Task ShowMessage(this Page page, string message, string title = null)
+        {
+            await page.DisplayAlert(title ?? page.Title, message, Resource.Ok);
+        }
     }
 
     public static class ModelExtensionHelper

Billing.Shared/UI/GroupStackLayout.cs

@@ -155,7 +155,8 @@ namespace Billing.UI
                     itemHeight = rowHeight;
                 }
                 var rect = new Rectangle(0, lastHeight, width, itemHeight);
-                item.Layout(rect);
+                //item.Layout(rect);
+                LayoutChildIntoBoundingRegion(item, rect);
                 lastHeight += itemHeight + spacing;
             }
         }

Billing.Shared/UI/OptionsCells.cs

@@ -245,7 +245,7 @@ namespace Billing.UI
             HorizontalOptions = LayoutOptions.End,
             VerticalOptions = LayoutOptions.Center
         }
-        .Binding(Switch.IsToggledProperty, nameof(IsToggled), BindingMode.TwoWay);
+        .Binding(Switch.IsToggledProperty, nameof(IsToggled), mode: BindingMode.TwoWay);
     }
 
     public class OptionEntryCell : OptionCell
@@ -283,7 +283,7 @@ namespace Billing.UI
                     VerticalOptions = LayoutOptions.Center,
                     ReturnType = ReturnType.Next
                 }
-                .Binding(Entry.TextProperty, nameof(Text), BindingMode.TwoWay)
+                .Binding(Entry.TextProperty, nameof(Text), mode: BindingMode.TwoWay)
                 .Binding(InputView.KeyboardProperty, nameof(Keyboard))
                 .Binding(Entry.PlaceholderProperty, nameof(Placeholder))
                 .DynamicResource(Entry.TextColorProperty, BaseTheme.TextColor)
@@ -334,7 +334,7 @@ namespace Billing.UI
             HorizontalOptions = LayoutOptions.Fill,
             VerticalOptions = LayoutOptions.Fill
         }
-        .Binding(Editor.TextProperty, nameof(Text), BindingMode.TwoWay)
+        .Binding(Editor.TextProperty, nameof(Text), mode: BindingMode.TwoWay)
         .Binding(Editor.FontSizeProperty, nameof(FontSize))
         .Binding(InputView.KeyboardProperty, nameof(Keyboard))
         .Binding(Editor.PlaceholderProperty, nameof(Placeholder))

Billing.Shared/Views/AccountPage.xaml

@@ -19,7 +19,7 @@
     </ContentPage.Resources>
 
     <ContentPage.ToolbarItems>
-        <ToolbarItem Order="Primary" IconImageSource="plus.png" Command="{Binding AddAccount}"/>
+        <ToolbarItem Order="Primary" IconImageSource="plus.png" Command="{Binding EditAccount}"/>
     </ContentPage.ToolbarItems>
 
     <ScrollView>
@@ -57,17 +57,21 @@
                 </ui:GroupStackLayout.GroupHeaderTemplate>
                 <ui:GroupStackLayout.ItemTemplate>
                     <DataTemplate x:DataType="m:Account">
-                        <StackLayout Orientation="Horizontal" Padding="20, 0, 10, 0" Spacing="10">
+                        <Grid Padding="20, 0, 10, 0" ColumnSpacing="10" ColumnDefinitions="Auto, *, Auto, Auto">
+                            <Grid.GestureRecognizers>
+                                <TapGestureRecognizer Command="{Binding EditAccount, Source={x:Reference accountPage}}"
+                                                      CommandParameter="{Binding .}"/>
+                            </Grid.GestureRecognizers>
                             <ui:TintImage Source="{Binding Icon, Converter={StaticResource iconConverter}}"
                                           WidthRequest="26" HeightRequest="20" VerticalOptions="Center"/>
-                            <Label Text="{Binding Name}" TextColor="{DynamicResource TextColor}"
+                            <Label Grid.Column="1" Text="{Binding Name}" TextColor="{DynamicResource TextColor}"
                                    HorizontalOptions="FillAndExpand" VerticalOptions="Center"
                                    FontSize="Default" FontAttributes="Bold"/>
-                            <Label Text="{Binding Balance, Converter={StaticResource money2Converter}}"
+                            <Label Grid.Column="2" Text="{Binding Balance, Converter={StaticResource money2Converter}}"
                                    TextColor="{DynamicResource SecondaryTextColor}"
                                    VerticalOptions="Center"/>
-                            <ui:TintImage Source="right.png" HeightRequest="20"/>
+                            <ui:TintImage Grid.Column="3" Source="right.png" HeightRequest="20"/>
-                        </StackLayout>
+                        </Grid>
                     </DataTemplate>
                 </ui:GroupStackLayout.ItemTemplate>
             </ui:GroupStackLayout>

Billing.Shared/Views/AccountPage.xaml.cs

@@ -19,14 +19,14 @@ namespace Billing.Views
         public decimal Liability => (decimal)GetValue(LiabilityProperty);
         public List<AccountGrouping> Accounts => (List<AccountGrouping>)GetValue(AccountsProperty);
 
-        public Command AddAccount { get; }
+        public Command EditAccount { get; }
 
         private readonly List<AccountGrouping> accounts = new();
         private bool initialized;
 
         public AccountPage()
         {
-            AddAccount = new Command(OnAddAccount);
+            EditAccount = new Command(OnEditAccount);
             SetValue(AccountsProperty, accounts);
 
             InitializeComponent();
@@ -40,9 +40,17 @@ namespace Billing.Views
                 accounts.Clear();
                 foreach (var account in App.Accounts)
                 {
+                    account.Balance = account.Initial + App.Bills.Where(b => b.WalletId == account.Id).Sum(b => b.Amount);
                     AddToAccountGroup(account);
                 }
             }
+            else
+            {
+                foreach (var account in App.Accounts)
+                {
+                    account.Balance = account.Initial + App.Bills.Where(b => b.WalletId == account.Id).Sum(b => b.Amount);
+                }
+            }
             groupLayout.Refresh(accounts);
         }
 
@@ -72,7 +80,7 @@ namespace Billing.Views
             }
         }
 
-        private async void OnAddAccount()
+        private async void OnEditAccount(object o)
         {
             if (Tap.IsBusy)
             {
@@ -80,7 +88,7 @@ namespace Billing.Views
             }
             using (Tap.Start())
             {
-                var page = new AddAccountPage();
+                var page = new AddAccountPage(o as Account);
                 page.AccountChecked += AccountChecked;
                 await Navigation.PushAsync(page);
             }
@@ -88,8 +96,11 @@ namespace Billing.Views
 
         private void AccountChecked(object sender, AccountEventArgs e)
         {
-            App.Accounts.Add(e.Account);
+            if (e.Account.Id < 0)
-            AddToAccountGroup(e.Account);
+            {
+                App.Accounts.Add(e.Account);
+                AddToAccountGroup(e.Account);
+            }
             groupLayout.Refresh(accounts);
 
             Task.Run(App.WriteAccounts);

Billing.Shared/Views/AddAccountPage.xaml

@@ -7,7 +7,6 @@
                 x:Class="Billing.Views.AddAccountPage"
                 x:Name="addAccountPage"
                 x:DataType="v:AddAccountPage"
-                Title="{r:Text AddAccount}"
                 BindingContext="{x:Reference addAccountPage}">
 
     <ContentPage.Resources>

Billing.Shared/Views/AddAccountPage.xaml.cs

@@ -49,29 +49,27 @@ namespace Billing.Views
 
         public event EventHandler<AccountEventArgs> AccountChecked;
 
-        public AddAccountPage()
+        public AddAccountPage(Account account = null)
-        {
-            CheckAccount = new Command(OnCheckAccount);
-            SelectIcon = new Command(OnSelectIcon);
-            SelectCategory = new Command(OnSelectCategory);
-
-            AccountIcon = BaseModel.ICON_DEFAULT;
-            Category = AccountCategory.Cash;
-            InitializeComponent();
-        }
-
-        public AddAccountPage(Account account)
         {
             CheckAccount = new Command(OnCheckAccount);
             SelectIcon = new Command(OnSelectIcon);
             SelectCategory = new Command(OnSelectCategory);
+            Title = Resource.EditAccount;
 
             this.account = account;
-            AccountName = account.Name;
+            if (account == null)
-            AccountIcon = account.Icon;
+            {
-            Category = account.Category;
+                AccountIcon = BaseModel.ICON_DEFAULT;
-            Initial = account.Initial.ToString();
+                Category = AccountCategory.Cash;
-            Memo = account.Memo;
+            }
+            else
+            {
+                AccountName = account.Name;
+                AccountIcon = account.Icon;
+                Category = account.Category;
+                Initial = account.Initial.ToString();
+                Memo = account.Memo;
+            }
             InitializeComponent();
         }
 
@@ -83,13 +81,26 @@ namespace Billing.Views
             }
             using (Tap.Start())
             {
+                if (string.IsNullOrWhiteSpace(AccountName))
+                {
+                    await this.ShowMessage(Resource.AccountRequired);
+                    return;
+                }
                 await Navigation.PopAsync();
                 _ = decimal.TryParse(Initial, out decimal initial);
+                if (account != null)
+                {
+                    account.Name = AccountName;
+                    account.Icon = AccountIcon;
+                    account.Category = Category;
+                    account.Initial = initial;
+                    account.Memo = Memo;
+                }
                 AccountChecked?.Invoke(this, new AccountEventArgs
                 {
-                    Account = new Account
+                    Account = account ?? new Account
                     {
-                        Id = account?.Id ?? -1,
+                        Id = -1,
                         Name = AccountName,
                         Icon = AccountIcon,
                         Category = Category,

Billing.Shared/Views/AddBillPage.xaml

@@ -16,27 +16,32 @@
     <ContentPage.Content>
         <TableView Intent="Settings" HasUnevenRows="True">
             <TableSection Title=" ">
-                <ui:OptionEditorCell Height="120" Icon="pencil.png" FontSize="20" Keyboard="Text"
+                <ui:OptionEditorCell Height="120" Icon="yuan.png" FontSize="20" Keyboard="Numeric"
-                                     Title="{r:Text Account}"
+                                     Text="{Binding Amount, Mode=TwoWay}"
-                                     Text="{Binding AccountName, Mode=TwoWay}"
                                      Placeholder="0.00"/>
             </TableSection>
             <TableSection>
                 <TableSection.Title>
                     <OnPlatform x:TypeArguments="x:String" Android=" "/>
                 </TableSection.Title>
+                <ui:OptionEntryCell Height="44" Icon="pencil.png"
+                                    Title="{r:Text Name}"
+                                    Text="{Binding Name, Mode=TwoWay}"
+                                    Placeholder="{r:Text NamePlaceholder}"/>
                 <ui:OptionSelectCell Height="44" Icon="project.png"
                                      Title="{r:Text Category}"
-                                     Detail="{Binding Category, Converter={StaticResource categoryConverter}}"
+                                     Detail="{Binding CategoryName}"
                                      Command="{Binding SelectCategory}"/>
-                <ui:OptionSelectCell Height="44" Icon="project.png"
+                <ui:OptionSelectCell Height="44" Icon="wallet.png"
                                      Title="{r:Text Account}"
-                                     Detail="{Binding Category, Converter={StaticResource categoryConverter}}"
+                                     Detail="{Binding WalletName}"
-                                     Command="{Binding SelectCategory}"/>
+                                     Command="{Binding SelectWallet}"/>
-                <ui:OptionSelectCell Height="44" Icon="project.png"
+                <ui:OptionEntryCell Height="44" Icon="online.png"
+                                    Title="{r:Text Store}"
+                                    Text="{Binding Store, Mode=TwoWay}"/>
+                <ui:OptionSelectCell Height="44" Icon="bars.png"
                                      Title="{r:Text CreatedTime}"
-                                     Detail="{Binding Category, Converter={StaticResource categoryConverter}}"
+                                     Detail="{Binding CreatedTime}"/>
-                                     Command="{Binding SelectCategory}"/>
             </TableSection>
             <TableSection>
                 <TableSection.Title>
@@ -44,7 +49,7 @@
                 </TableSection.Title>
                 <ui:OptionEditorCell Height="120" Icon="note.png" Keyboard="Plain"
                                      Title="{r:Text Memo}"
-                                     Text="{Binding Memo, Mode=TwoWay}"
+                                     Text="{Binding Note, Mode=TwoWay}"
                                      Placeholder="{r:Text MemoPlaceholder}"/>
             </TableSection>
         </TableView>

Billing.Shared/Views/AddBillPage.xaml.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Globalization;
+using System.Linq;
 using Billing.Languages;
 using Billing.Models;
 using Billing.UI;
@@ -8,28 +10,158 @@ namespace Billing.Views
 {
     public partial class AddBillPage : BillingPage
     {
+        private static readonly BindableProperty AmountProperty = BindableProperty.Create(nameof(Amount), typeof(string), typeof(AddBillPage));
+        private static readonly BindableProperty NameProperty = BindableProperty.Create(nameof(Name), typeof(string), typeof(AddBillPage));
+        private static readonly BindableProperty CategoryNameProperty = BindableProperty.Create(nameof(CategoryName), typeof(string), typeof(AddBillPage));
+        private static readonly BindableProperty WalletNameProperty = BindableProperty.Create(nameof(WalletName), typeof(string), typeof(AddBillPage));
+        private static readonly BindableProperty StoreProperty = BindableProperty.Create(nameof(Store), typeof(string), typeof(AddBillPage));
+        private static readonly BindableProperty CreatedTimeProperty = BindableProperty.Create(nameof(CreatedTime), typeof(DateTime), typeof(AddBillPage));
+        private static readonly BindableProperty NoteProperty = BindableProperty.Create(nameof(Note), typeof(string), typeof(AddBillPage));
+
+        public string Amount
+        {
+            get => (string)GetValue(AmountProperty);
+            set => SetValue(AmountProperty, value);
+        }
+        public string Name
+        {
+            get => (string)GetValue(NameProperty);
+            set => SetValue(NameProperty, value);
+        }
+        public string CategoryName => (string)GetValue(CategoryNameProperty);
+        public string WalletName => (string)GetValue(WalletNameProperty);
+        public string Store
+        {
+            get => (string)GetValue(StoreProperty);
+            set => SetValue(StoreProperty, value);
+        }
+        public DateTime CreatedTime
+        {
+            get => (DateTime)GetValue(CreatedTimeProperty);
+            set => SetValue(CreatedTimeProperty, value);
+        }
+        public string Note
+        {
+            get => (string)GetValue(NoteProperty);
+            set => SetValue(NoteProperty, value);
+        }
+
         public Command CheckBill { get; }
+        public Command SelectCategory { get; }
+        public Command SelectWallet { get; }
+
+        public event EventHandler<Bill> BillChecked;
 
         private readonly Bill bill;
         private readonly DateTime createDate;
 
+        private int walletId;
+        private int categoryId;
+
         public AddBillPage(DateTime date)
         {
             createDate = date;
             CheckBill = new Command(OnCheckBill);
+            SelectCategory = new Command(OnSelectCategory);
+            SelectWallet = new Command(OnSelectWallet);
             InitializeComponent();
             Title = Resource.AddBill;
+
+            Initial();
         }
 
         public AddBillPage(Bill bill)
         {
             this.bill = bill;
             CheckBill = new Command(OnCheckBill);
+            SelectCategory = new Command(OnSelectCategory);
+            SelectWallet = new Command(OnSelectWallet);
             InitializeComponent();
             Title = Resource.EditBill;
+
+            Initial();
         }
 
-        private void OnCheckBill()
+        private void Initial()
+        {
+            if (bill != null)
+            {
+                Amount = bill.Amount.ToString(CultureInfo.InvariantCulture);
+                Name = bill.Name;
+                walletId = bill.WalletId;
+                categoryId = bill.CategoryId;
+                SetValue(WalletNameProperty, App.Accounts.FirstOrDefault(a => a.Id == walletId)?.Name);
+                SetValue(CategoryNameProperty, App.Categories.FirstOrDefault(c => c.Id == categoryId)?.Name);
+                Store = bill.Store;
+                CreatedTime = bill.CreateTime;
+                Note = bill.Note;
+            }
+            else
+            {
+                var first = App.Accounts.First();
+                walletId = first.Id;
+                SetValue(WalletNameProperty, first.Name);
+                var firstCategory = App.Categories.First();
+                categoryId = firstCategory.Id;
+                SetValue(CategoryNameProperty, firstCategory.Name);
+                CreatedTime = createDate.Date.Add(DateTime.Now.TimeOfDay);
+            }
+        }
+
+        private async void OnCheckBill()
+        {
+            if (Tap.IsBusy)
+            {
+                return;
+            }
+            using (Tap.Start())
+            {
+                if (!decimal.TryParse(Amount, out decimal amount))
+                {
+                    return;
+                }
+                if (amount == 0)
+                {
+                    await this.ShowMessage(Resource.AmountRequired);
+                    return;
+                }
+                amount = Math.Abs(amount);
+                var category = App.Categories.FirstOrDefault(c => c.Id == categoryId);
+                if (category.Type == CategoryType.Spending)
+                {
+                    amount *= -1;
+                }
+                await Navigation.PopAsync();
+                if (bill != null)
+                {
+                    bill.Amount = amount;
+                    bill.Name = Name;
+                    bill.CategoryId = categoryId;
+                    bill.WalletId = walletId;
+                    bill.CreateTime = CreatedTime;
+                    bill.Store = Store;
+                    bill.Note = Note;
+                }
+                BillChecked?.Invoke(this, bill ?? new Bill
+                {
+                    Id = -1,
+                    Amount = amount,
+                    Name = Name,
+                    CategoryId = categoryId,
+                    WalletId = walletId,
+                    CreateTime = CreatedTime,
+                    Store = Store,
+                    Note = Note
+                });
+            }
+        }
+
+        private void OnSelectCategory()
+        {
+
+        }
+
+        private void OnSelectWallet()
         {
 
         }

Billing.Shared/Views/BillPage.xaml

@@ -30,6 +30,10 @@
         </Grid>
     </Shell.TitleView>
 
+    <ContentPage.ToolbarItems>
+        <ToolbarItem Order="Primary" IconImageSource="plus.png" Command="{Binding EditBilling}"/>
+    </ContentPage.ToolbarItems>
+
     <Grid RowDefinitions="Auto, Auto, *">
         <ui:BillingDate x:Name="billingDate" SelectedDate="{Binding SelectedDate}" DateSelected="OnDateSelected"/>
         <Grid Grid.Row="1" Padding="8" ColumnSpacing="8" ColumnDefinitions="Auto, *, Auto"
@@ -39,7 +43,7 @@
                    VerticalOptions="Center"/>
             <StackLayout Grid.Column="2" Orientation="Horizontal" Spacing="6">
                 <StackLayout.GestureRecognizers>
-                    <TapGestureRecognizer Command="{Binding AddBilling}"/>
+                    <TapGestureRecognizer Command="{Binding EditBilling}"/>
                 </StackLayout.GestureRecognizers>
                 <Label Text="{r:Text TapToMemo}" TextColor="{DynamicResource PrimaryColor}"
                        VerticalOptions="Center"/>
@@ -48,11 +52,16 @@
         </Grid>
         <!-- bill list -->
         <ScrollView Grid.Row="2">
-            <ui:GroupStackLayout x:Name="billsLayout" ItemsSource="{Binding Bills}" Margin="0, 10, 0, 0">
+            <ui:GroupStackLayout x:Name="billsLayout" ItemsSource="{Binding Bills}"
+                                 Margin="0, 10, 0, 0" RowHeight="50">
                 <ui:GroupStackLayout.ItemTemplate>
                     <DataTemplate x:DataType="v:UIBill">
                         <Grid Padding="20, 0, 10, 0" ColumnSpacing="10"
                               ColumnDefinitions="Auto, *, Auto" RowDefinitions="Auto, Auto">
+                            <Grid.GestureRecognizers>
+                                <TapGestureRecognizer Command="{Binding EditBilling, Source={x:Reference billPage}}"
+                                                      CommandParameter="{Binding .}"/>
+                            </Grid.GestureRecognizers>
                             <ui:TintImage Source="{Binding Icon, Converter={StaticResource iconConverter}}"
                                           WidthRequest="26" HeightRequest="20" VerticalOptions="Center"/>
                             <Label Grid.Column="1" Text="{Binding Name}" TextColor="{DynamicResource TextColor}"
@@ -62,7 +71,7 @@
                                    TextColor="{Binding Amount, Converter={StaticResource colorConverter}}"
                                    VerticalOptions="Center"/>
                             <Label Grid.Row="1" Grid.Column="1" Text="{Binding ., Converter={StaticResource billConverter}}"
-                                   FontSize="Small"
+                                   FontSize="10"
                                    TextColor="{DynamicResource SecondaryTextColor}"/>
                         </Grid>
                     </DataTemplate>

Billing.Shared/Views/BillPage.xaml.cs

@@ -1,8 +1,10 @@
+using Billing.Languages;
 using Billing.Models;
 using Billing.UI;
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using Xamarin.Forms;
 
 namespace Billing.Views
@@ -23,11 +25,11 @@ namespace Billing.Views
             set => SetValue(BillsProperty, value);
         }
 
-        public Command AddBilling { get; }
+        public Command EditBilling { get; }
 
         public BillPage()
         {
-            AddBilling = new Command(OnAddBilling);
+            EditBilling = new Command(OnEditBilling);
 
             InitializeComponent();
 
@@ -42,14 +44,28 @@ namespace Billing.Views
                 b.CreateTime.Year == e.Date.Year &&
                 b.CreateTime.Month == e.Date.Month &&
                 b.CreateTime.Day == e.Date.Day);
-            Bills = new List<UIBill>(bills.Select(b => new UIBill(b)
+            Bills = new List<UIBill>(bills.Select(b => WrapBill(b)));
+        }
+
+        private UIBill WrapBill(Bill b)
+        {
+            return new UIBill(b)
             {
                 Icon = App.Categories.FirstOrDefault(c => c.Id == b.CategoryId)?.Icon ?? BaseModel.ICON_DEFAULT,
                 Name = b.Name,
                 DateCreation = b.CreateTime,
                 Amount = b.Amount,
                 Wallet = App.Accounts.FirstOrDefault(a => a.Id == b.WalletId)?.Name
-            }));
+            };
+        }
+
+        private void UpdateBill(UIBill bill)
+        {
+            bill.Icon = App.Categories.FirstOrDefault(c => c.Id == bill.Bill.CategoryId)?.Icon ?? BaseModel.ICON_DEFAULT;
+            bill.Name = bill.Bill.Name;
+            bill.DateCreation = bill.Bill.CreateTime;
+            bill.Amount = bill.Bill.Amount;
+            bill.Wallet = App.Accounts.FirstOrDefault(a => a.Id == bill.Bill.WalletId)?.Name;
         }
 
         private void OnTitleDateLongPressed(object sender, EventArgs e)
@@ -57,7 +73,7 @@ namespace Billing.Views
             billingDate.SetDateTime(DateTime.Now);
         }
 
-        private async void OnAddBilling()
+        private async void OnEditBilling(object o)
         {
             if (Tap.IsBusy)
             {
@@ -65,10 +81,55 @@ namespace Billing.Views
             }
             using (Tap.Start())
             {
-                var page = new AddBillPage(SelectedDate);
+                AddBillPage page;
+                if (o is UIBill bill)
+                {
+                    page = new AddBillPage(bill.Bill);
+                }
+                else
+                {
+                    if (App.Accounts.Count == 0)
+                    {
+                        await this.ShowMessage(Resource.NeedAccount);
+                        await Shell.Current.GoToAsync("//Accounts");
+                        return;
+                    }
+                    page = new AddBillPage(SelectedDate);
+                }
+                page.BillChecked += OnBillChecked;
                 await Navigation.PushAsync(page);
             }
         }
+
+        private void OnBillChecked(object sender, Bill e)
+        {
+            if (e.Id < 0)
+            {
+                int maxId;
+                if (App.Bills.Count > 0)
+                {
+                    maxId = App.Bills.Max(b => b.Id);
+                }
+                else
+                {
+                    maxId = -1;
+                }
+                e.Id = maxId + 1;
+                App.Bills.Add(e);
+                Bills.Add(WrapBill(e));
+                billsLayout.Refresh(Bills);
+            }
+            else
+            {
+                var bill = Bills.FirstOrDefault(b => b.Bill == e);
+                if (bill != null)
+                {
+                    UpdateBill(bill);
+                }
+            }
+
+            Task.Run(App.WriteBills);
+        }
     }
 
     public class UIBill : BindableObject