scan Documents on device

scan.kt

    /** List of extension file paths */
    override fun scan(folders: List<Uri>, extensions: Regex): List<DocumentFile> {
        val result = mutableListOf<DocumentFile>()

        fun scan(root: DocumentFile?, extensions: Regex, outputUris: MutableList<DocumentFile>) {
            if (root == null) return
            val name = root.name
            if (root.isFile && name != null && name.contains(extensions)) {
                outputUris.add(root)
                return
            }
            if (root.isDirectory) {
                root.listFiles().forEach {
                    scan(it, extensions, outputUris)
                }
            }
        }
        // scan file tree
        folders.forEach { uri ->
            scan(DocumentFile.fromTreeUri(context, uri), extensions, result)
        }

        logd(result.map { it.uri }, "video files")

        return result
    }