Check if there are files in device folder

[HenReeco]

Hi.

I'm developing an app that collects some raw data from my fitbit ionic, saves them to files, and then send those data to the phone (i have to do that using the Message API).

So far so good: in my testing, I can write to file and send it to the companion app just fine.

For my data collection though, I would like to collect a bunch of data through different activities, and collect a bunch of files, that I would later send to the companion app. So I would need some kind of recursive search (or maybe I should just say a search, since I think we can't create any folder) that allows me to send files as long as there are any available (I delete files from the device every time they are sent to the companion app).

Is there any function that browses in the file system and allows me to do that? 
If not, I was thinking that I could just work on some kind of report file where I check what has been sent and what not. In that case, is it possible to read a row at a time in the file, or should I just come up with a specific format that allows me to read a buffer of a fixed size each time?

Hope everything makes sense.

Thank you.

[JonFitbit]

I have some stuff which will make your life a lot easier, I will get back to you in a few days.

[HenReeco]

any news? or do you have an extimate date of when you'll get in touch?

[JonFitbit]

I should be able to give you more info next week, sorry for the delay,

[aquintanilla]

Jon, I'm developing something very similar. Wondering if you guys ever came up with an approach for this.

[Gondwana · Accepted solution]

Jon may have been alluding to File Directory Listings.