Error when writing bitmap to directory even with directory access-CodePudding

What I want to do: After the user chooses a directory/folder (and thus allows the app access), I want to write a bitmap to that directory. However, I get this error when writing that bitmap:

Caused by: java.io.FileNotFoundException: /storage/emulated/0/ChosenFolderByUser/output.jpg: open failed: EPERM (Operation not permitted)

Why does this happen since the user has granted access to files in the chosen directory? Here's my code:

private val dirPickerHandler = registerForActivityResult(
    ActivityResultContracts.StartActivityForResult()
) {
    if (it.data != null) {

        val uri = it.data?.data!!

        contentResolver.takePersistableUriPermission(
            uri,
            Intent.FLAG_GRANT_READ_URI_PERMISSION or
                    Intent.FLAG_GRANT_WRITE_URI_PERMISSION
        )

        grantUriPermission(
            packageName,
            uri,
            Intent.FLAG_GRANT_READ_URI_PERMISSION or
                    Intent.FLAG_GRANT_WRITE_URI_PERMISSION or
                    Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION
        )

        val path = URLDecoder.decode(uri.toString(), "UTF-8")
        val dPath = cleanPath(path)

        showMessage("Storage location successfully updated to $dPath")

        val mIcon = BitmapFactory.decodeResource(getResources(), R.drawable.image_to_save)
        // Write bitmap to directory chosen by user - Error here:
        File(Environment.getExternalStorageDirectory().toString()   "/"   dPath, "output.jpg").writeBitmap(mIcon, Bitmap.CompressFormat.JPEG, 85)

    } else {
        showMessage(
            getString(R.string.no_directory_selected)
        )
    }
}

companion object {
    fun cleanPath(path: String): String {

        if (path.isEmpty()) {
            return "DCIM/Camera"
        }

        val s = URLDecoder.decode(path, "UTF-8")
        return s.substring(s.lastIndexOf(":")   1)
    }
}

private fun File.writeBitmap(bitmap: Bitmap, format: Bitmap.CompressFormat, quality: Int) {
    outputStream().use { out ->
        bitmap.compress(format, quality, out)
        out.flush()
    }
}

CodePudding user response：

Remove the call for grantUriPermission() as it does not make sense.

Dont try to get a path for an uri.

Dont use the File class for an Uri.

You are not showing where the used output stream comes from.

CodePudding user response：

You cannot use Environment.getExternalStorageDirectory() for target SDK 31. You should use scope storage. Please read more about it here: https://developer.android.com/about/versions/11/privacy/storage

If you want to use the legacy way, you should have the target SDK 30 (max) and in case it is 30, then you should enable requestLegacyExternalStorage.