Function to recursively copy files from an Android asset directory

gistfile1.kt

private fun copyFileOrDir(path: String) {
    val assetManager = this.assets
    try {
        val assets = assetManager.list(path)
        if (assets!!.isEmpty()) {
            copyFile(path)
        } else {
            val dir = File("${applicationInfo.dataDir}/${path}")
            if (!dir.exists()) dir.mkdir()
            for (i in assets.indices) {
                copyFileOrDir("${path}/${assets[i]}")
            }
        }
    } catch (ex: IOException) {
        Log.e("CopyFile", "I/O Exception", ex)
    }
}

private fun copyFile(filename: String) {
    val assetManager = this.assets
    try {
        val source = assetManager.open(filename)
        val target = FileOutputStream("${applicationInfo.dataDir}/${filename}")
        val buffer = ByteArray(1024)
        var read: Int
        while (source.read(buffer).also { read = it } != -1) {
            target.write(buffer, 0, read)
        }
        source.close()
        target.flush()
        target.close()
    } catch (e: Exception) {
        Log.e("CopyFile", e.message)
    }
}