Transfering (large) files between app and module.

[DecentWoodpecker67]

I've hit a problem I need some ideas for. I've written a module that hooks into an app and changes a few things. This app does also play sound files which are embedded in the hooked app APK as resources, and what I want to do is to give the user the ability to change what sound is being played. Currently I want the user to select a sound file in my app and then somehow transfer this file to the hooked app so that I can play it there instead of the original file. I already have the infrastructure for that, except that I do not know how to get the file to the hooked app.

I know that LSPosed offers the ability to replace resources in the APK, but as far as I can see that does not give me the ability to replace it with a user selected file (a dynamic one). The app which I'm hooking does also not declare the necessary permissions in its manifest for this API level to access (sound) files, so I can't simply request the permissions at runtime either. Additionally, I can't use Content Providers as far as I know, because this too requires permissions in the manifest at this API level to work. I can't send the file through Intents (as I do with the other preferences), because Intents have a quite small max size.

So far the only option I'm seeing is transferring the file to the app data directory (utilizing root privileges) and then play it from there.

Has somebody got an idea?