Xamarin.Forms Directory Picker - xamarin.forms

Question

I would like to save a file in a user selected folder, thats why I would like to provide a directory list to user and user will be able to choose the directory where he wants to export the data. Unfortuntely I could not find any example for directory/folder picker, I just found a file picker which is not useful for me..
https://github.com/jfversluis/FilePicker-Plugin-for-Xamarin-and-Windows
Is there any component for picking a folder for Xamarin.Forms? Actually I am just doing for Android but we use Xamarin.forms

Answer 1

There is none I can think of.
With netstandard everything is way more simple as you can use the classic c# File api to get the folders.
You just have to know the mappings between special folders and android folders (per example):
System.Environment.SpecialFolder Path
ApplicationData INTERNAL_STORAGE/.config
Desktop INTERNAL_STORAGE/Desktop
LocalApplicationData INTERNAL_STORAGE/.local/share
MyDocuments INTERNAL_STORAGE
MyMusic INTERNAL_STORAGE/Music
MyPictures INTERNAL_STORAGE/Pictures
MyVideos INTERNAL_STORAGE/Videos
Personal INTERNAL_STORAGE
source: https://learn.microsoft.com/en-US/xamarin/android/platform/files/
same for ios:
https://learn.microsoft.com/en-US/xamarin/ios/app-fundamentals/file-system
But it's really easy to implement, just enumerate all folders and display them in a ListView.
EDIT: more details on implementation.
In fact you want to code a "directory explorer", it's easy, here is the concept.
You have a ListView in your Page
You have a Cancel button and a Select button in your Page
You have a CurrentPath in your ViewModel
You bind CurrentPath to the Title of your Page
You have an List<DirectoryViewModel> Directories in your ViewModel
Each time a user click on a item from the list:
You add the directory name in your current path
You get all the directories from the new path, and update your Directories property (don't forget RaisePropertyChange(nameof(Directories)))
The ListView will be updated accordingly
Each time you back:
You remove last part of your current path
same as before
If you arrive to root path "/", you do nothing when clicking on back.
Oh and you could use this Grid component to instead of the ListView, will be nicer ;)
https://github.com/roubachof/Sharpnado.Presentation.Forms#grid-Layout

Answer 2

You can edit this to make it work..
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Java.IO;
using Java.Util;
namespace Android.Basic.IO
{
public class DirectoryPicker : ListActivity
{
public const String START_DIR = "startDir";
public const String ONLY_DIRS = "onlyDirs";
public const String SHOW_HIDDEN = "showHidden";
public const String CHOSEN_DIRECTORY = "chosenDir";
public const int PICK_DIRECTORY = 43522;
private File dir;
private Boolean showHidden = false;
private bool onlyDirs = true;
public override void OnCreate(Bundle savedInstanceState, PersistableBundle persistentState)
{
base.OnCreate(savedInstanceState, persistentState);
Bundle extras = Intent.Extras;
dir = OS.Environment.ExternalStorageDirectory;
if (extras != null)
{
String preferredStartDir = extras.GetString(START_DIR);
showHidden = extras.GetBoolean(SHOW_HIDDEN, false);
onlyDirs = extras.GetBoolean(ONLY_DIRS, true);
if (preferredStartDir != null)
{
File startDir = new File(preferredStartDir);
if (startDir.IsDirectory)
{
dir = startDir;
}
}
}
SetContentView(Resource.Layout.folder_chooser_activity);
var title = dir.AbsolutePath.ToString();
Title = (title);
Button btnChoose = (Button)FindViewById(Resource.Id.btnChoose);
String name = dir.Name;
if (name.Length == 0)
name = "/";
btnChoose.Text = ("Choose " + "'" + name + "'");
btnChoose.Click += delegate
{
returnDir(dir.AbsolutePath);
};
ListView lv = this.ListView;
lv.TextFilterEnabled = (true);
if (!dir.CanRead())
{
Context context = ApplicationContext;
String msg = "Could not read folder contents.";
Toast.MakeText(context, msg, ToastLength.Long).Show();
return;
}
var files = filter(dir.ListFiles(), onlyDirs, showHidden);
String[] names = Names(files);
ListAdapter = (new ArrayAdapter<String>(this, Resource.Layout.folder_chooser_item, names));
lv.ItemClick += (ff, gg) =>
{
var position = gg.Position;
if (!files[gg.Position].IsDirectory)
return;
String path = files[position].AbsolutePath;
var intent = new Intent(this, typeof(DirectoryPicker));
intent.PutExtra(DirectoryPicker.START_DIR, path);
intent.PutExtra(DirectoryPicker.SHOW_HIDDEN, showHidden);
intent.PutExtra(DirectoryPicker.ONLY_DIRS, onlyDirs);
StartActivityForResult(intent, PICK_DIRECTORY);
};
}
protected void OnActivityResult(int requestCode, int resultCode, Intent data)
{
if (requestCode == PICK_DIRECTORY && resultCode == (int)Result.Ok)
{
Bundle extras = data.Extras;
String path = (String)extras.Get(DirectoryPicker.CHOSEN_DIRECTORY);
returnDir(path);
}
}
private void returnDir(String path)
{
Intent result = new Intent();
result.PutExtra(CHOSEN_DIRECTORY, path);
SetResult(Result.Ok, result);
Finish();
}
public List<File> filter(File[] file_list, bool onlyDirs, bool showHidden)
{
var files = new List<File>();
foreach (var file in file_list)
{
if (onlyDirs && !file.IsDirectory)
continue;
if (!showHidden && file.IsHidden)
continue;
files.Add(file);
}
Collections.Sort(files);
return files;
}
public String[] Names(List<File> files)
{
String[] names = new String[files.Count];
int i = 0;
foreach (var file in files)
{
names[i] = file.Name;
i++;
}
return names;
}
}
}
Start activity as result then catch in OnActivityResult
if (requestCode == DirectoryPicker.PICK_DIRECTORY && resultCode == Result.Ok)
{
Bundle extras = data.Extras;
String path = (String)extras.Get(DirectoryPicker.CHOSEN_DIRECTORY);
// do stuff with path
}