I am developing a data-logging app using Android Studio. I want to save a file that will appear on the user's home screen.
Is there a way to save/write a text file that will appear directly on the home screen of the phone, rather than in internal storage? I don't want to just create a shortcut—I actually want the file to be saved on the home screen.
Is this possible? If so, how can I do it?
This isn't possible. The Android home screen (also known as the launcher) is just an app like any other app. It doesn't correspond to any location on the filesystem where you could store files.
A user may have multiple home apps installed (though only one can be set as the active one) each with their own independent home layout. Some launcher apps don't even take the sort of traditional icon-centric approach to a home screen that you may be used to.
The only way to achieve this feature would be to do what you said you do not want to do: create a shortcut that opens the file.