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CANNOT_CREATE_FILE_IN_TARGET when attempting to save on external drive
Library version: 1.5.1 OS version: [Android 11] Device model: [Samsung Galaxy A8]
Describe the bug When invoking DocumentFileUtils.MoveFileTo targeting a folder stored on an external drive (USB SSD in my example) the movement fails.
If the target folder is an internal folder, the move succeeds
Full file permission has been granted, the external folder has been selected using OPEN_DOCUMENT_TREE
To Reproduce
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give application full file permissions
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select target folder using ACTION_OPEN_DOCUMENT_TREE
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select file that will be moved
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start background thread
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check file can be read and location can be written to
DocumentFileUtils.moveFileTo([any file], this, [Folder on external drive], null, new FileCallBack(){}
Stacktrace [If applicable]
This issue is similar to #8. Adding support for USB mass storage has low priority for now. In the past, I've tried to add it, but I found the complexity is extremely high. So I decided to revert the changes. It will ruin the entire code in the current project, and the regression will be insane. Why? Because:
- The USB APIs are poorly designed and not following the SOLID principle. When you use the function in your code, it is compiled successfully, but when executing it will throw
java.lang.NoSuchMethodError
. - Some required functions are only available as internal/hidden APIs.
- The API changes are too frequent, it's hard to maintain the compatibility across the OS versions.
- Hard to predict the APIs behavior and their patterns.
- Too many rules from the official documentation.
- There's no emulator that can simulate the USB. So we are able to test the code on physical devices only. You can see the AVD here only has two options for the storage (internal & SD card):

Maintaining the compatibility for internal storage and SD card is already hard. Adding USB support will be a nightmare for me. I only maintain the repository during my spare time. I will leave this issue open until an undetermined time, or when I get enlightened.