Add support for picking a directory

[kinex]

Usage scenario: To export data from an app user must be able to select an output directory where to save the file. Tip for iOS implementation: see UIDocumentPickerMode.ExportToService

[kgamecarter]

Android implementation
https://github.com/googlesamples/android-DirectorySelection

[miguelpruivo]

This was actually wip to the current deployed version 1.3.0, however, this should be more discussed as Android actually allows it but iOS don't.

In iOS we usually either use the share capabilities to save/send some data or we use the app's data container to keep it. If we want to retrieve some directory it is possible but I believe that a concrete file pick is always required.

I was trying to avoid platform-specific features with this plugin and it's been already a tough task to fulfill because they differ fairly in the way they handle file picking. Nevertheless, I'm up to suggestions.

[rockgecko-development]

When I select a directory via getMultiFilePath via iCloud Drive, I get a folder containing .<orig name>.icloud files, of 175 bytes each.
I suppose this is because iCloud doesn't download the entire directory when you select it, unlike for individual files. But what do i do with these .icloud files, and how do I get the originals?

[miguelpruivo]

@rockgecko-development you are saying that you are able to select a folder when multi picking files?

[rockgecko-development]

@miguelpruivo yes.
Steps to reproduce:
iPhone 6, iOS 12
Call getMultiFilePath (it's not possible to select a folder in iCloud Drive with getFilePath)
Under Locations, choose iCloud Drive, then in the top bar press Select, which displays checkboxes for each item. Select a folder, then Open
In the result map, you get a folder which contains the .<orig name>.icloud placeholder files. Do you know what to do with these?

[miguelpruivo]

Thank you @rockgecko-development. Definitely I wasn’t expecting folders of being able to be picked in iOS so that’s probably the issue.

I’ll certainly look forward this in a future update.

[miguelpruivo]

Moved to #99.