Usage of MediaStore API

FileUtils.kt

val contentResolver = this.contentResolver
val contentValues = ContentValues().apply {
    put(MediaStore.MediaColumns.DISPLAY_NAME, "applounge")
    put(MediaStore.MediaColumns.MIME_TYPE, "text/plain")
    put(MediaStore.MediaColumns.RELATIVE_PATH, Environment.DIRECTORY_DOCUMENTS)
}

val uri = contentResolver.insert(MediaStore.Files.getContentUri("external"), contentValues)
uri?.let {
    contentResolver.openOutputStream(it)?.use { outputStream ->
        outputStream.write(fullMessage.toByteArray())
        outputStream.close()
    }
}