Android: Request permissions

[nomeata]

My Android app should write some files to /sdcard. It seems that if I add

    permissions = ''
      <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    '';

to the call to buildApp and then manually in the App’s settings enable these permissions, I can access the /sdcard. So that’s a start.

But clearly, the proper way is to ask the system at runtime to give the app these permissions.

Is that supported from Haskell (somehow)?

[ali-abrar]

The behavior used to be that when you tried to use a permission that had not been granted, the authorization modal would appear. Somewhere along the way that must have stopped working, probably due to changes in how the android sdk.

Relevant documentation

Relevant code in android-activity

I'll look into this. Is the app you're building open source? Perhaps I can use that as a test.

[ali-abrar]

Oh, I see. kaleidogen.

Is there a particular branch I should build?

[nomeata]

This was just an experiment so far, but yeah, check branch android-writing-files.

You should be able to build the app using nix-build -A android. After changing the path from /home/jojo/build/haskell/reflex/reflex-platform in default.nix to something else…

[nomeata]

Maybe I shouldn’t worry about writing to storage, and instead write to the app-internal storage and then use the “send intent” to share the file. But I fear that accessing the API to invoke intents from Haskell is no easier than asking for extra permissions (and I guess in general using any feature of the Android API from Haskell, without writing Java and JNI stuff, is going to be too tricky).

[nomeata]

I wonder if http://hackage.haskell.org/package/jvm would work on Android…

[nomeata]

Doesn’t look like it (yet): tweag/inline-java#92

[nomeata]

Coming back to this (every few months I am trying to make small improvements). Did your investigation lead to anything? Do you have any apps that save files?