val File.listFilesFolderFirst: List<File>
    get() {
        val mutableList = listFiles().toMutableList()
        Collections.sort(mutableList, { file1: File, file2: File ->
            if ((file1.isDirectory && file2.isDirectory) || (file1.isFile && file2.isFile)) {
                return@sort 0
            } else {
                if (file1.isDirectory) {
                    return@sort -1
                } else {
                    return@sort 1
                }
            }
        })
        return mutableList
    }