[Scummvm-tracker] [ScummVM :: Bugs] #12727: ANDROID: Allow Save location in SDcard (Write permission on SD)

[ScummVM :: Bugs]

#12727: ANDROID: Allow Save location in SDcard (Write permission on SD)
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Reporter:  LukasThyWalls                         |       Owner:  (none)
    Type:  feature request                       |      Status:  new
Priority:  normal                                |   Component:  Port:
                                                 |  Android
 Version:                                        |  Resolution:
Keywords:  Android, SDCard, Write permission,    |        Game:
  Savegames, Feature request                     |
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Comment (by antoniou79):

 Replying to [comment:2 LukasThyWalls]:
 >
 > No, i am not getting it. I tried to choose the (real) sdcard directory
 root (''/storage/9016-4EF8/''), the directory i want
 (''/Juegos/ScummVM/Saves/'') but i'm not getting a "system" browser to
 allow writing. The only thing i have is a message saying "The chosen
 directory cannot be written to. Please select another one".
 > Other apps like SyncMe Wireless or NewPipe do the thing you described
 and they do it and then they can use the SD to write, but ScummVM is not
 doing this.
 >
 Then a lot more testing is needed. SAF is supposed to bring up the "System
 file picker". I'm on a Redmi Note 9 pro (Android 10), MUI 12.0.4 stable
 and am getting that picker interface. (There's a new system update pending
 though, so this is subject to change I guess).

 It's just as well, because we need to:
 - add further checks for when a permission is granted not at root level
 but at folder level (most tests where done with permission at root level)
 - support possible UTF-8 characters in paths
 - test for save game functionality specifically (the feature was mostly
 tested for the ScummVM LAN server)
 - probably implement a way to revoke permissions granted with this browser
 or
 - recycle old ones as iirc there's a limit on how many of those
 permissions we can have for ScummVM

 >
 > It's something i wanted to report, because is happening for a while. I
 have this phone since more than two years and it never do this if i
 recall.
 > I didn't report earlier because i remember reading something about this
 issue and people from ScummVM team saying they don't wanna fix it because
 is an issue of Android itself for changing the framework again and again
 and they don't wanna spend time in their constant changes... but it has
 been a while since then, and now i remembered this and i don't find any of
 that messages here, in open or closed tickets. Maybe they are in the
 forums, or i have dreamed them...
 >
 That would probably be me, complaining about Google API updates. It's not
 that I don't want to fix the issues that come up. It's that I'm not an
 Android expert, not a dedicated Android porter and that the solutions are
 rarely straightforward. And testing requires a lot of time on multiple
 emulator configurations and devices, and the constant and serious API
 updates keep requiring more maintenance or updating of the code -- a time
 that I prefer to spend elsewhere (eg. like the Blade Runner engine).

 I do not express the sentiment of the whole team, though. Just my own
 thoughts on the matter. We all do work on a voluntary basis and each has
 their own priority on tasks to be worked on. I have a few Android devices
 and I would like ScummVM to run smoothly on them, so that's my main
 motivation on working on it.

 Also keep in mind, in the last 2 years the Android port got a major
 update, to bring it up-to-date with the ScummVM core features and new game
 engines. And we keep hacking at bugs and improving existing features when
 possible and when time and life allows.

 Anyway here's my summary of it. Android (Google) has radically tightened
 security wrt what an app can do with storage (and other stuff, but here
 we're mostly interested in storage). Unfortunately the ScummVM paradigm is
 not really the standard app they have in mind making these changes. And
 they do keep changing stuff which makes maintenance a chore for developers
 of apps outside the self-contained app norm, like ScummVM.

 Ideally we will keep/fix supporting storing on an SD card in the newer
 Android versions, which seems like the proper thing to do, but jumping
 through hoops to achieve that is diminishing for any enthusiasm and
 motivation.

 Also, the listing of directories (the second issue addressed in this
 ticket) is (again) going to have to change, since as of sometime this
 year, and in Android 11 and above, some of the functions we use to find
 the available storage options will cease to work (as deprecated). And this
 is yet another potentially huge thing to deal with, since Android vendors
 are very inconsistent in following a standard for external storage, so you
 cannot have hardcoded paths, and the code for accommodating all cases
 becomes a spaghetti nightmare.

 >
 > I point that out because maybe is related to the other issue, but if you
 can access to all the directories needed it's not an issue, and looking
 where go all the shorcuts, you can go where you need.
 > I'm only saying the names doesn't match where they go and they are a
 little confussing: At least in my phone, the ''sdcard'' is not the real
 sdcard, is the internal storage, the ''data (ext)'' is the ScummVM data in
 internal storage, and the ''data (int)'', is the /data directory in the
 "system"? storage (or whatever is called, the root linux partition what
 have all the OS), what also is empty for me because is unnaccessible
 without root.
 Again, that's Android for you. And its onomatopoeia.
 They have a system "sdcard" folder, but it does not correspond to the
 user's external sd card (I think it never did).
 Then, an Android app has an internal storage and an external storage, but
 both of those are actually allocated in "internal" storage space. And both
 will get deleted (wiped) when uninstalling the app. App external storage
 differs from App internal storage only in that external storage can be
 accessed from other apps, but internal cannot. Both of these storages are
 guaranteed to exist -- they don't depend on external physical storage, and
 the app has access to these spaces always without requiring permissions to
 read/write. These are the ONLY spaces a modern Android OS app is allowed
 to write without asking for explicit permissions.

 I think the other link (ScummVM data) is there for compatibility with
 older versions of Android OS (and ScummVM).

 Anyway...
 ScummVM has implemented LAN server and Cloud Saving, so those could be
 used to work around the storage nightmares, at least until we (hopefully)
 sort out this new API stuff.
-- 
Ticket URL: <https://bugs.scummvm.org/ticket/12727#comment:3>
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