PCLStorage NuGet use

logcat.txt

# initial run:
I mono-stdout: # jonp: rootFolder=/data/user/0/scratch.furkanerasian_pclstorage/files
I mono-stdout: # jonp: file=/data/user/0/scratch.furkanerasian_pclstorage/files/MySubFolder/answer.txt

# second run:
I mono-stdout: # jonp: rootFolder=/data/user/0/scratch.furkanerasian_pclstorage/files
I mono-stdout: # jonp: existing text:
I mono-stdout: 42
I mono-stdout: # jonp: file=/data/user/0/scratch.furkanerasian_pclstorage/files/MySubFolder/answer.txt

MainActivity.cs

using System;

using Android.App;
using Android.Widget;
using Android.OS;
using System.Threading.Tasks;

using PCLStorage;

namespace FurkanErasian_PclStorage
{
	[Activity (Label = "FurkanErasian_PclStorage", MainLauncher = true, Icon = "@mipmap/icon")]
	public class MainActivity : Activity
	{
		int count = 1;

		protected override async void OnCreate (Bundle savedInstanceState)
		{
			base.OnCreate (savedInstanceState);

			// Set our view from the "main" layout resource
			SetContentView (Resource.Layout.Main);

			await PCLStorageSample ();

			// Get our button from the layout resource,
			// and attach an event to it
			Button button = FindViewById<Button> (Resource.Id.myButton);

			button.Click += delegate { button.Text = $"{count++} clicks!"; };
		}

		public async Task PCLStorageSample ()
		{
			IFolder rootFolder = FileSystem.Current.LocalStorage;
			Console.WriteLine ($"# jonp: rootFolder={rootFolder.Path}");
			IFolder folder = await rootFolder.CreateFolderAsync ("MySubFolder",
				CreationCollisionOption.OpenIfExists);
			if (await folder.CheckExistsAsync ("answer.txt") == ExistenceCheckResult.FileExists) {
				var existing = await folder.GetFileAsync ("answer.txt");
				var curText = await existing.ReadAllTextAsync ();
				Console.WriteLine ("# jonp: existing text:");
				Console.WriteLine (curText);
			}
			IFile file = await folder.CreateFileAsync ("answer.txt",
				CreationCollisionOption.ReplaceExisting);
			Console.WriteLine ($"# jonp: file={file.Path}");
			await file.WriteAllTextAsync ("42");
		}
	}
}