Xamarin Android write to SD card shared storage

Question

I want to implement functionality that allows an Android user to write a file to their devices SD card and have the ability to pop that SD card into a different device and access the file from the new device - in case their original device is damaged and no longer usable.

I'm able to write to the SD card, getting the path like so:

Java.IO.File[] externalFilesDirs = Android.App.Application.Context.GetExternalFilesDirs(null);

if (externalFilesDirs.Any())
{
    string externalSdPath = externalFilesDirs.Length > 1 ? externalFilesDirs[1].AbsolutePath :  externalFilesDirs[0].AbsolutePath; 
}

However, this stores the file in an app-specific folder that I'm unable to access from another app, or the same app on a different device.

I'm targeting Android 11 and I know that scoped storage is the standard now, but is there any way to write to a non-app specific folder on the SD card or access the app-specific folder outside of the app that created it?

Have you seen: https://commonsware.com/blog/2019/10/11/storage-situation-removable-storage.html — Morrison Chang, Mar 14 '23 at 20:47

score 0 · Answer 1 · answered Mar 14 '23 at 21:03

0

Standard now is using SAF.

Storage Access Framework.

Let the user select the removable micro sd card with ACTION_OPEN_DOCUMENT_TREE.

After that you can create files on it until full.

answered Mar 14 '23 at 21:03

blackapps

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score 0 · Answer 2 · answered Mar 15 '23 at 06:30

You can use this code to make the user to access the sd card.

startActivityForResult(new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE), requestCode);

Here is the answer you can refer to Android M write to SD Card.

More information you can check this article about Grant access to a directory's contents

Xamarin Android write to SD card shared storage

2 Answers2