Unable to access external USB storage via OTG cable

[Peter Njeim]

Hello,

Dolphin on Android's built-in file manager is lacking the ability to request permission for accessing USB storage devices. Another type of storage that is inaccessible through the built-in file manager are network locations.

If this is too much to ask for to be built into the in-house file manager, I think it's possible to implement a feature that allows users to use their preferred file managers and use the Share button to open the file in Dolphin, though I find this possible workaround non-ideal.

When a file manager app tries to access a USB storage device, it will ask for permission. Dolphin simply does not ask for permission, hence not being able to access the device. Arbitrary USB device path: /mnt/media_rw/<random-hex-id>. Documentation on how to obtain r/w access to USB devices is found here: https://developer.android.com/guide/topics/connectivity/usb/host.

Ideally, Dolphin should not have a built-in file manager and simply use the default file manager of the user, and use a built-in file manager as a fallback if no file manager exists, this way, the fallback file manager would not need to be feature rich (as is the case now) and users who want more functionality will simply be guided to download their preferred file manager and use that with Dolphin instead.

Any updates to the implementation of more storage access options would be great, in any manner.

Kind regards,
Peter

[mbc07]

Not that simple. Apps that request file access through the "built-in" Android file manager you're referring are actually using SAF (Storage Access Framework) API, and last time I checked there was a lot of implications on how files requested through SAF API could be accessed, especially on native code like Dolphin's core and when considering that "virtual" filesystems (e.g. a cloud drive account) can also be returned through SAF. Another issue is that we provide Android TV compatibility and Android TV doesn't ship with the built-in "DocumentsUI" system app, so even if we switched to SAF, the request would fail when running on Android TV as there's no UI for it.

Then, there's the new scoped storage requirements on Android 10, which is on top of that another issue to deal with. We'll eventually have to rewrite the code responsible for file access to account for all of that but it's definitely not as trivial as it sounds and considering we currently don't have any active developer working on the Android port, don't expect anything to be done until Google bumps the minimum targetAPI required to publish updates to the Play Store or until someone volunteers to do the job -- it doesn't necessarily need to be an active developer as we are open-source so anyone can contribute...