How can I share a db file between 2 applications

Question

since Enviroment.getExternalStorageDirectory() is deprecated I have a little Problem. I have 2 applications (a lite and a pro version of an app). These apps have a database which I could export and import. When switching from lite to pro app, the user could import the "old" database into the new app. The database was stored under a folder inside his "sdcard". But now on Android 12 devices we no longer have access to that External Storage.

So how could I solve the problem?

Cause I think, context.getExternalFilesDir((Environment.DIRECTORY_DOCUMENTS) doesn't work cause the namespace of both apps are different. And I guess it will not work to open a file which is not located under the namespace of the app the file is requested.

Answer 1

I found a solution by myself, but if someone else is looking for a solution it might be helpful.

I ask the user to specify a file location via

Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
intent.addCategory(Intent.CATEGORY_OPENABLE);
intent.setType("application/db");
intent.putExtra(Intent.EXTRA_TITLE, "xyz.db");

mCreateNewDatabaseFile.launch(intent);

then in the mCreateNewDatabaseFile

private final ActivityResultLauncher<Intent> mCreateNewDatabaseFile = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), result -> {
    if (result.getResultCode() == RESULT_OK) {
        if (result.getData() != null && result.getData().getData() != null) {
            Uri path = result.getData().getData();
            getContentResolver().takePersistableUriPermission(path, Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
            getContentResolver().takePersistableUriPermission(path, Intent.FLAG_GRANT_READ_URI_PERMISSION);
            mPreferences.edit().putString(PREF_KEY_DATABASE_EXPORT_PATH, path.toString()).apply();
        }
    }
});

So even with another process I can read and write the file.

So in the lite Version I can create the db file and in the pro version I can let the user choose this file for import.

I hope it will help others with similar questions.