XamarinSQLite教程在Xamarin.Android項(xiàng)目中使用數(shù)據(jù)庫
在Xamarin.Android項(xiàng)目中使用預(yù)設(shè)數(shù)據(jù)庫的具體操作步驟如下：
（1）創(chuàng)建一個(gè)Xamarin.Android項(xiàng)目，如AndroidSQLiteDemo。
（2）在AndroidSQLiteDemo項(xiàng)目的Resources文件夾下創(chuàng)建一個(gè)Raw文件夾。
（3）將上一節(jié)中創(chuàng)建的Documents.db數(shù)據(jù)庫拖動(dòng)到Raw文件夾中。
（4）打開MainActivity.cs文件，將Documents.db數(shù)據(jù)庫的內(nèi)容復(fù)制到/data/data/[your packageName/files/ MyDocuments.db中，代碼如下：
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("數(shù)據(jù)庫文件的目錄：{0}",path);
?if (!File.Exists(path))
?{
?var s = Resources.OpenRawResource(Resource.Raw.Documents);
?//創(chuàng)建寫入列
?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);
?//?寫入所需字節(jié)
?while (bytesRead > 0)
?{
?writeStream.Write(buffer, 0, bytesRead);
?bytesRead = readStream.Read(buffer, 0, Length);
?}
?readStream.Close();
?writeStream.Close();
?}
?}
}
運(yùn)行程序后，初始狀態(tài)如圖1.31所示。
輕拍HELLO WORLD,CLICK ME!按鈕后，會(huì)在輸出窗口輸出以下的內(nèi)容：
數(shù)據(jù)庫文件的目錄：/data/user/0/com.company.AndroidSQLiteDemo/files/MyDocuments.db
此時(shí)Documents.db數(shù)據(jù)庫中的內(nèi)容就會(huì)復(fù)制到MyDocuments.db文件中。
