I'm not sure where else to post this, but I'm looking for a third party Android app where I can create notes directly from a widget and save them in the Joplin folder. Also would Joplin recognize them as unfiled notes?
I just checked one called "markor offline markdown editor" and the Joplin mobile app did not recognize it. I'll put in a feature request for this.
I don't think you'll find such an app, if I understood correctly what you mean.
Joplin's file format (the one used for sync) is a custom one, despite the file extension suggesting it's markdown. You'd need another app to implement this format. Admittedly it isn't super complicated, but why would they want to do it.
Not sure if it helps but you can create notes if you long press on the app icon and select new note/todo.