Use asyn method for synchronous Sqlite on createMethod - sqlite

Question

I'm using Xamarin, also my SQLite tables contain a large amount of data.
Because I want to avoid UIThread problems in OnCreate(), I need to perform database actions asynchronously.
I'm looking for guidance if I am handling this properly.
First method, which I found on the net:
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.InventoryPreviewMain);
Thread thread = new Thread(() =>
{
SQLiteConnection db = new SQLiteConnection(dpPath);
var table = db.Query<InventoryPreviewClass>("select * from InventoryPreviewClass where CategoryID =" + Connection.CategoryID + "");
mItems = new List<InventoryPreviewClass>();
foreach (var item in table)
{
mItems.Add(new InventoryPreviewClass() { InventoryItemID = item.InventoryItemID, InventoryItemName = item.InventoryItemName, InventoryItemPrice = item.InventoryItemPrice });
}
MyListViewAdapterInventory adapter = new MyListViewAdapterInventory(this, Resource.Layout.InventoryPreview, mItems);
mlistview.Adapter = adapter;
});
thread.Start();
Second Method, using async
public async void StartTimer()
{
SQLiteConnection db = new SQLiteConnection(dpPath);
var table = db.Query<InventoryPreviewClass>("select * from InventoryPreviewClass where CategoryID =" + Connection.CategoryID + "");
mItems = new List<InventoryPreviewClass>();
foreach (var item in table)
{
mItems.Add(new InventoryPreviewClass() { InventoryItemID = item.InventoryItemID, InventoryItemName = item.InventoryItemName, InventoryItemPrice = item.InventoryItemPrice });
}
MyListViewAdapterInventory adapter = new MyListViewAdapterInventory(this, Resource.Layout.InventoryPreview, mItems);
mlistview.Adapter = adapter;
await Task.Delay(500);
}
Which of two examples are more safe for keeping alive UIthread? Is there any other solution for making this?What is more reccomended to do?

Answer 1

Answer
Use the Cross-platform SQLite Library made by #FrankKruger to create/access SQLite databases for Xamarin mobile apps.
This library has a built-in asynchronous connection, so you'll never need to worry about accessing the database from the UI Thread again!
Xamarin.Android Example
"Second Method"
public async Task StartTimer()
{
mItems = await InventoryPreviewClassDatabase.GetAllInventoryPreviewClassAsync();
MyListViewAdapterInventory adapter = new MyListViewAdapterInventory(this, Resource.Layout.InventoryPreview, mItems);
mlistview.Adapter = adapter;
}
BaseDatabase Class
using System;
using System.Threading.Tasks;
using SQLite;
namespace SampleApp
{
public abstract class BaseDatabase
{
#region Constant Fields
static readonly Lazy<SQLiteAsyncConnection> _databaseConnectionHolder = new Lazy<SQLiteAsyncConnection>(() => GetDatabaseConnection());
#endregion
#region Fields
static bool _isInitialized;
#endregion
#region Properties
static SQLiteAsyncConnection DatabaseConnection => _databaseConnectionHolder.Value;
#endregion
#region Methods
protected static async Task<SQLiteAsyncConnection> GetDatabaseConnectionAsync()
{
if (!_isInitialized)
await Initialize().ConfigureAwait(false);
return DatabaseConnection;
}
static async Task Initialize()
{
await DatabaseConnection.CreateTableAsync<InventoryPreviewClass>().ConfigureAwait(false);
_isInitialized = true;
}
SQLiteAsyncConnection GetDatabaseConnection()
{
var sqliteFilename = "YourDatabaseName.db3";
string documentsPath = System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal); // Documents folder
var path = Path.Combine(documentsPath, sqliteFilename);
var conn = new SQLiteAsyncConnection(path, SQLiteOpenFlags.ReadWrite | SQLiteOpenFlags.Create | SQLiteOpenFlags.SharedCache);
return conn;
}
#endregion
}
}
Parent Database Class
using System.Linq;
using System.Threading.Tasks;
using System.Collections.Generic;
namespace SampleApp
{
public abstract class InventoryPreviewClassDatabase : BaseDatabase
{
#region Methods
public static async Task<IList<InventoryPreviewClass>> GetAllInventoryPreviewClassAsync()
{
var databaseConnection = await GetDatabaseConnectionAsync().ConfigureAwait(false);
return await databaseConnection.Table<InventoryPreviewClass>().ToListAsync().ConfigureAwait(false);
}
public static async Task<InventoryPreviewClass> GetInventoryPreviewClassByIDAsync(int id)
{
var databaseConnection = await GetDatabaseConnectionAsync().ConfigureAwait(false);
return await databaseConnection.Table<InventoryPreviewClass>().Where(x => x.ID.Equals(id)).FirstOrDefaultAsync().ConfigureAwait(false);
}
public static async Task<int> SaveInventoryPreviewClassAsync(InventoryPreviewClass inventoryPreview)
{
var databaseConnection = await GetDatabaseConnectionAsync().ConfigureAwait(false);
var isObjectInDatabase = await GetInventoryPreviewClassByIDAsync(inventoryPreview.ID).ConfigureAwait(false) != null;
if (isObjectInDatabase)
return await databaseConnection.UpdateAsync(inventoryPreview).ConfigureAwait(false);
return await databaseConnection.InsertAsync(inventoryPreview).ConfigureAwait(false);
}
public static async Task<int> DeleteItemAsync(OpportunityModel opportunity)
{
var databaseConnection = await GetDatabaseConnectionAsync().ConfigureAwait(false);
return await databaseConnection.DeleteAsync(opportunity).ConfigureAwait(false);
}
public static async Task<int> GetNumberOfRowsAsync()
{
var databaseConnection = await GetDatabaseConnectionAsync().ConfigureAwait(false);
return await databaseConnection.Table<InventoryPreviewClass>().CountAsync().ConfigureAwait(false);
}
#endregion
}
}
This code was inspired from this Xamarin.Forms sample app