Here App.xaml.cs's code


```
using SQLite;
using System;
using System.IO;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;

namespace App111
{
    public partial class App : Application
    {
        SQLiteAsyncConnection Database;
        public App()
        {
            InitializeComponent();
            Database = new SQLiteAsyncConnection(Constants.DatabasePath, Constants.Flags);

            var result = Database.CreateTableAsync<TodoItem>();
            MainPage = new MainPage();
        }

        protected override void OnStart()
        {
        }

        protected override void OnSleep()
        {
        }

        protected override void OnResume()
        {
        }
    }

    internal class TodoItem
    {
        public string ID { get; set; }
    }

    public static class Constants
    {
        public const string DatabaseFilename = "Fruits.db";

        public const SQLite.SQLiteOpenFlags Flags =
            // open the database in read/write mode
            SQLite.SQLiteOpenFlags.ReadWrite |
            // create the database if it doesn't exist
            SQLite.SQLiteOpenFlags.Create |
            // enable multi-threaded database access
            SQLite.SQLiteOpenFlags.SharedCache;

        public static string DatabasePath
        {
            get
            {
                var basePath = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
                return Path.Combine(basePath, DatabaseFilename);
            }
        }
    }
}

```


here is MainPage.xaml.cs

```
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;

namespace App111
{
    public partial class MainPage : ContentPage
    {
        public MainPage()
        {
            InitializeComponent();
        }

        private void Button_Clicked(object sender, EventArgs e)
        {
             DependencyService.Get<ICopy>().CopyDB();

            //Navigation.PushModalAsync(new Page1());
        }
    }
}

```

Here is MainPage.xaml

```
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="App111.MainPage">

    <StackLayout>
        <Button Text="Copy" Clicked="Button_Clicked"></Button>
    </StackLayout>

</ContentPage>

```

Here is ICopy interface.

```
using System;
using System.Collections.Generic;
using System.Text;

namespace App111
{
    public interface ICopy
    {
        void CopyDB();
    }
}

```


Then open your App111.Android project

Find MainActivity.cs

```
using System;

using Android.App;
using Android.Content.PM;
using Android.Runtime;
using Android.OS;
using Google.Android.Material.Snackbar;
using Android.Views;
using Android.Content;

namespace App111.Droid
{
    
    [Activity(Label = "App111", Icon = "@mipmap/icon", Theme = "@style/MainTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation | ConfigChanges.UiMode | ConfigChanges.ScreenLayout | ConfigChanges.SmallestScreenSize )]
    
    public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

          var path=  Android.OS.Environment.ExternalStorageDirectory.AbsolutePath;

          var InternalPath=  Android.App.Application.Context.GetExternalFilesDir("").AbsolutePath;

            if (Build.VERSION.SdkInt >= BuildVersionCodes.R)
            {

           
                if (!Android.OS.Environment.IsExternalStorageManager)
                {
                    Snackbar.Make(FindViewById(Android.Resource.Id.Content), "Permission needed!", Snackbar.LengthIndefinite)
                            .SetAction("Settings", new MyOnClickListener(this)).Show();
                }
            }
            Xamarin.Essentials.Platform.Init(this, savedInstanceState);
            global::Xamarin.Forms.Forms.Init(this, savedInstanceState);
            LoadApplication(new App());
        }
        public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Android.Content.PM.Permission[] grantResults)
        {
            Xamarin.Essentials.Platform.OnRequestPermissionsResult(requestCode, permissions, grantResults);

            base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }

    internal class MyOnClickListener : Java.Lang.Object, View.IOnClickListener
    {
        private MainActivity mainActivity;
        public MyOnClickListener()
        {
        }
        public MyOnClickListener(MainActivity mainActivity)
        {
            this.mainActivity = mainActivity;
        }
        public void OnClick(View v)
        {
            // throw new System.NotImplementedException();ACTION_MANAGE_APP_ALL_FILES_ACCESS_PERMISSION
            try
            {
                mainActivity.StartActivity(new Intent(
    Android.Provider.Settings.ActionManageAllFilesAccessPermission,
    Android.Net.Uri.Parse("package:" + Android.App.Application.Context.PackageName)));

            }
            catch (Exception ex)
            {
                Intent intent = new Intent();
                intent.SetAction(Android.Provider.Settings.ActionManageAllFilesAccessPermission);
                mainActivity.StartActivity(intent);
            }
        }
    }

}
```

create a class called MyCopyService.cs

```
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using App111.Droid;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using Xamarin.Forms;

[assembly: Dependency(typeof(MyCopyService))]
namespace App111.Droid
{
    class MyCopyService : ICopy
    {
        public void CopyDB()
        {
            Java.IO.File mediaStorageDir = new Java.IO.File(Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryDocuments) + "/MyDB");

            if (!mediaStorageDir.Exists())
            {
                var tt = mediaStorageDir.Mkdirs();
                if (mediaStorageDir.Mkdirs() == false)
                {
                    var fail = "failed to create";
                }
            }

            var directoryPath = mediaStorageDir.AbsolutePath;
         
         
            var dbPath = Path.Combine(System.Environment.GetFolderPath(System.Environment.SpecialFolder.ApplicationData), "Fruits.db");
            FileInfo file = new FileInfo(dbPath);
            var dbName = file.Name;
            var fullFileName = string.Concat("/", dbName );
            var newpath = string.Format("{0}{1}", directoryPath, fullFileName);

         

            byte[] dbFile = System.IO.File.ReadAllBytes(dbPath);
            System.IO.File.WriteAllBytes(newpath, dbFile);

          
        }


    }
}
```