项目代码可以从Github下载：https://github.com/zhenl/ZL.Shudu 。代码随项目进度更新。
现在我们增加添加新游戏的功能，创建一个页面，编辑初始局面，并保存到数据库。
我们首先了解一下Xamarin中页面如何跳转。首先，需要为跳转的页面增加路由，这需要在AppShell中增加下面的代码：
public AppShell()
{
InitializeComponent();
Routing.RegisterRoute(nameof(GameEdit), typeof(GameEdit));
Routing.RegisterRoute(nameof(GameList), typeof(GameList));
}
GameEdit和GameList是两个页面，GameList中显示数据库中现有的游戏列表，GameEdit用来编辑或新建游戏。通过GameList中的新建游戏按钮或者选择列表中现有的项目，可以跳转到GameEdit。在GameEdit中可以返回到GameList。导航的代码如下：
GameList中新建游戏的代码如下：
async void btn_NewGame_Clicked(object sender, EventArgs e)
{
await Shell.Current.GoToAsync($"{nameof(GameEdit)}?{nameof(GameEdit.ItemId)}=0");
}GameList中选中现有项目，跳转到GameEdit的代码如下：
async void Handle_ItemTapped(object sender, ItemTappedEventArgs e)
{
if (e.Item == null)
return;
await Shell.Current.GoToAsync($"{nameof(GameEdit)}?{nameof(GameEdit.ItemId)}={e.Item}");
}
在GameEdit中，还需要定义接收传入的参数，这里传入的参数是ItemId，在GameEdit的声明中使用QueryProperty标记声明传入参数:
[QueryProperty(nameof(ItemId), nameof(ItemId))]
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class GameEdit : ContentPage在接收ItemId时，从数据库中读取相应的记录并初始化页面:
public string ItemId
{
get
{
return currentId.ToString();
}
set
{
currentId = int.Parse( value);
if (currentId > 0)
{
var game = App.Database.GetGameAsync(currentId).Result;
if(game != null) EditGame(game);
}
}
}下面是GameList和GameEdit的完整代码。
GameList页面代码：
GameList后台代码：
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
namespace ZL.Shudu.Views
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class GameList : ContentPage
{
public ObservableCollection Items { get; set; }
public GameList()
{
InitializeComponent();
}
protected override async void OnAppearing()
{
await RefreshList();
}
public async Task RefreshList()
{
Items = await GetItems();
MyListView.ItemsSource = Items;
MyListView.IsVisible = true;
}
public async Task> GetItems()
{
var items = new ObservableCollection();
var lst = await App.Database.GetGamesAsync();
foreach (var obj in lst)
{
items.Add(obj.ID.ToString());
}
return items;
}
async void Handle_ItemTapped(object sender, ItemTappedEventArgs e)
{
if (e.Item == null)
return;
await Shell.Current.GoToAsync($"{nameof(GameEdit)}?{nameof(GameEdit.ItemId)}={e.Item}");
}
async void btn_NewGame_Clicked(object sender, EventArgs e)
{
await Shell.Current.GoToAsync($"{nameof(GameEdit)}?{nameof(GameEdit.ItemId)}=0");
}
}
} GameEdit页面代码：
GameEdit后台代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
using ZL.Shudu.Services;
namespace ZL.Shudu.Views
{
[QueryProperty(nameof(ItemId), nameof(ItemId))]
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class GameEdit : ContentPage
{
private bool IsSaved=false;
private int currentId = 0;
private static int[,] chess = new int[9, 9];
private Button[,] buttons = new Button[9, 9];
private Button[,] numbuttons = new Button[2, 5];
private Button currentButton;
private Button currentNumBtn;
public string ItemId
{
get
{
return currentId.ToString();
}
set
{
currentId = int.Parse( value);
if (currentId > 0)
{
var game = App.Database.GetGameAsync(currentId).Result;
if(game != null) EditGame(game);
}
}
}
public GameEdit()
{
InitializeComponent();
SetLayout();
SetNumButtons();
}
internal void EditGame(InputGameInfo game)
{
currentId = game.ID;
for (var i = 0; i < 9; i++)
for (var j = 0; j < 9; j++)
{
chess[i, j] = int.Parse(game.Sudoku.Substring(i * 9 + j, 1));
buttons[i, j].Text = chess[i, j] > 0 ? chess[i, j].ToString() : "";
buttons[i, j].IsEnabled = true;
}
}
private void SetNumButtons()
{
var num = 1;
for (var i = 0; i < 2; i++)
{
for (var j = 0; j < 5; j++)
{
var btn = new Button();
if (num == 10)
{
btn.Text = "清除";
btn.Clicked += Clear_Clicked;
btn.FontSize = 15;
}
else
{
btn.Text = num.ToString();
btn.Clicked += Num_Clicked;
btn.FontSize = 16;
}
btn.Padding = 0;
grdNumber.Children.Add(btn, j, i);
numbuttons[i, j] = btn;
num++;
}
}
}
private void SetLayout()
{
for (var i = 0; i < 9; i++)
{
for (var j = 0; j < 9; j++)
{
int m = i / 3;
int n = j / 3;
var btn = new Button();
var c = new Color(0.9, 0.9, 0.9);
if ((m + n) % 2 == 0)
{
c = new Color(0.7, 0.7, 0.7);
}
btn.BackgroundColor = c;
btn.Padding = 0;
btn.Margin = 0;
btn.FontSize = 20;
myGrid.Children.Add(btn, i, j);
btn.Clicked += Btn_Clicked;
buttons[i, j] = btn;
}
}
}
private async void btn_Save_Clicked(object sender, EventArgs e)
{
var str = "";
for (var i = 0; i < 9; i++)
for (var j = 0; j < 9; j++)
{
if (string.IsNullOrEmpty(buttons[i, j].Text))
chess[i, j] = 0;
else
chess[i, j] = int.Parse(buttons[i, j].Text);
str += chess[i, j].ToString();
}
var newgame = new InputGameInfo
{
Sudoku = str,
InputDate = DateTime.Now
};
if (currentId > 0)
{
newgame.ID = currentId;
await App.Database.UpdateGameAsync(newgame);
}
else
{
currentId = await App.Database.SaveGameAsync(newgame);
}
lbMessage.Text = "保存成功";
lbMessage.IsVisible = true;
}
private void btn_New_Clicked(object sender, EventArgs e)
{
lbMessage.Text = "";
currentId = 0;
for (var i = 0; i < 9; i++)
for (var j = 0; j < 9; j++)
{
buttons[i, j].Text = "";
buttons[i, j].IsEnabled = true;
chess[i, j] = 0;
}
}
private void Btn_Clicked(object sender, EventArgs e)
{
currentButton = sender as Button;
rowResult.Height = 1;
rowButton.Height = 1;
grdNumber.IsVisible = true;
}
private async void btn_Delete_Clicked(object sender, EventArgs e)
{
if (currentId > 0)
{
await App.Database.DeleteGameAsync(new InputGameInfo { ID = currentId });
await Shell.Current.GoToAsync($"///{nameof(GameList)}");
}
}
private void Num_Clicked(object sender, EventArgs e)
{
currentNumBtn = sender as Button;
int x = -1, y = -1;
for (var i = 0; i < 9; i++)
{
for (var j = 0; j < 9; j++)
{
if (buttons[i, j] == currentButton)
{
x = i;
y = j;
break;
}
}
}
var num = int.Parse(currentNumBtn.Text);
currentButton.Text = currentNumBtn.Text;
myGrid.IsVisible = true;
grdNumber.IsVisible = false;
rowResult.Height = 40;
rowButton.Height = 40;
}
private void Clear_Clicked(object sender, EventArgs e)
{
if (currentButton == null) return;
currentButton.Text = "";
grdNumber.IsVisible = false;
myGrid.IsVisible = true;
rowResult.Height = 40;
rowButton.Height = 40;
}
private async void btn_Back_Clicked(object sender, EventArgs e)
{
await Shell.Current.GoToAsync($"///{nameof(GameList)}");
}
}
}编辑功能完成了，但还有一个问题，如果输入的游戏无法完成怎么办？这需要增加判断游戏是否可以完成的逻辑，如果无法完成，需要将UsedInGame属性设置为false，避免无效游戏。
在输入新的游戏时，我们需要确保输入的游戏合法并且能够完成，在输入过程中，可能需要随时检查合法性，在保存之前，需要确保游戏合法且可完成，然后才能保存。验证的方法就是使用计算机算法完成数独游戏，如果可以完成，就是合法的，否则就需要修改。相关的算法已经封装在程序包中，实现细节在这里不做讨论，将来会作为独立的文章详细介绍实现过程。可以使用Nuget程序包管理器进行安装：ZL.Sudoku.Lib。使用方法如下：
var comp = new FindOneSolution(cinp);
var res = comp.Comp();
var fchess = comp.Matrix;
上面算法中，cinp是输入的数独数组，使用Comp方法进行计算，如果res=2，说明计算完成，输出的结果使用Matrix属性获得，也是一个二维数组。如果res=1，说明无法完成，如果是其它值说明输入有错误。
安装完这个程序包后，我们可以改造GameEdit页面。首先增加一个按钮，用来在输入过程中验证是否合法和能够完成。
后台代码：
private void btn_Check_Clicked(object sender, EventArgs e)
{
if (btn_Check.Text == "检查")
{
var cinp = getChess();
lastinput = cinp;
var comp = new FindOneSolution(cinp);
var res = comp.Comp();
var fchess = comp.Matrix;
for (var i = 0; i < 9; i++)
{
for (var j = 0; j < 9; j++)
{
var btn = buttons[i, j];
if (cinp[i, j] > 0)
{
btn.Text = cinp[i, j].ToString();
}
else
{
btn.Text = fchess[i, j] > 0 ? fchess[i, j].ToString() : "";
}
}
}
if (res == 0) lbMessage.Text = "不合法";
else if (res == 1) lbMessage.Text = "计算不出来";
else if (res == 2) lbMessage.Text = "计算完成";
else lbMessage.Text = "其它错误";
btn_Check.Text = "继续";
}
else
{
lbMessage.Text = "";
btn_Check.Text = "检查";
for (var i = 0; i < 9; i++)
{
for (var j = 0; j < 9; j++)
{
var btn = buttons[i, j];
if (lastinput[i, j] > 0)
{
btn.Text = lastinput[i, j].ToString();
}
else
{
btn.Text ="";
}
}
}
}
}
private int[,] getChess()
{
var res = new int[9, 9];
for (var i = 0; i < 9; i++)
{
for (var j = 0; j < 9; j++)
{
var btn = buttons[i, j];
if(string.IsNullOrEmpty(btn.Text)) res[i,j]= 0;
else res[i, j]=int.Parse(btn.Text);
}
}
return res;
}在保存前，也需要进行检查，如果不合法或者无法完成，就提示继续编辑，不能保存：
private async void btn_Save_Clicked(object sender, EventArgs e)
{
if(btn_Check.Text=="继续") btn_Check_Clicked(null,null);
var str = "";
var chess = getChess();
for (var i = 0; i < 9; i++)
for (var j = 0; j < 9; j++)
{
str += chess[i, j].ToString();
}
var comp = new FindOneSolution(chess);
var res = comp.Comp();
if(res != 2)
{
lbMessage.Text = "不合法或者无法完成的游戏，请修改后保存";
return;
}
var newgame = new InputGameInfo
{
Sudoku = str,
InputDate = DateTime.Now,
UsedInGame = true
};
if (currentId > 0)
{
newgame.ID = currentId;
await App.Database.UpdateGameAsync(newgame);
}
else
{
currentId = await App.Database.SaveGameAsync(newgame);
}
lbMessage.Text = "保存成功";
}到此，我们的数独游戏基本完成。下一步的工作是增加完成历史列表页面，让玩家查看已经完成的历史，并且能够复盘。