XamarinSQLite教程在Xamarin.Android项目中使用数据库

在Xamarin.Android项目中使用预设数据库的具体操作步骤如下：

(1)创建一个Xamarin.Android项目，如AndroidSQLiteDemo。

(2)在AndroidSQLiteDemo项目的Resources文件夹下创建一个Raw文件夹。

(3)将上一节中创建的Documents.db数据库拖动到Raw文件夹中。

(4)打开MainActivity.cs文件，将Documents.db数据库的内容复制到/data/data/[your packageName/files/ MyDocuments.db中，代码如下：

using System;

using Android.App;

using Android.Content;

using Android.Runtime;

using Android.Views;

using Android.Widget;

using Android.OS;

using Android.Support.V7.App;

using System.IO;

using System.Text;

namespace AndroidSQLiteDemo

{

[Activity(Label = "@string/app_name", MainLauncher = true, LaunchMode = Android.Content.PM.LaunchMode.SingleTop, Icon = "@drawable/icon")]

public class MainActivity : AppCompatActivity

{

protected override void OnCreate(Bundle bundle)

{

base.OnCreate(bundle);

SetContentView(Resource.Layout.main);

var toolbar = FindViewById(Resource.Id.toolbar);

if (toolbar != null)

{

SetSupportActionBar(toolbar);

SupportActionBar.SetDisplayHomeAsUpEnabled(false);

SupportActionBar.SetHomeButtonEnabled(false);

}

// Get our button from the layout resource,

// and attach an event to it

var clickButton = FindViewById(Resource.Id.my_button);

clickButton.Click += (sender, args) =>

{

var sqliteFilename = "MyDocuments.db";

string documentsPath = System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal); // Documents folder

var path = Path.Combine(documentsPath, sqliteFilename);

Console.WriteLine("数据库文件的目录：{0}",path);

if (!File.Exists(path))

{

var s = Resources.OpenRawResource(Resource.Raw.Documents);

//创建写入列

FileStream writeStream = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Write);

ReadWriteStream(s, writeStream);

}

};

}

void ReadWriteStream(Stream readStream, Stream writeStream)

{

int Length = 256;

Byte[] buffer = new Byte[Length];

int bytesRead = readStream.Read(buffer, 0, Length);

// 写入所需字节

while (bytesRead > 0)

{

writeStream.Write(buffer, 0, bytesRead);

bytesRead = readStream.Read(buffer, 0, Length);

}

readStream.Close();

writeStream.Close();

}

}

}

运行程序后，初始状态如图1.31所示。

轻拍HELLO WORLD,CLICK ME!按钮后，会在输出窗口输出以下的内容：

数据库文件的目录：/data/user/0/com.company.AndroidSQLiteDemo/files/MyDocuments.db

此时Documents.db数据库中的内容就会复制到MyDocuments.db文件中。