MainActivity.kt

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        if (resultCode == RESULT_OK) {
            when (requestCode) {
                REQUEST_CODE_SINGLE_SELECT -> {
                    val uri = data?.data
                    // Do stuff with uri
                }
                REQUEST_CODE_MULTI_SELECT -> {
                    var mediaCount = 0
                    while (mediaCount < data?.clipData!!.itemCount) {
                        val uri = data.clipData!!.getItemAt(mediaCount).uri
                        // Do stuff with uri
                        mediaCount++
                    }
                }
            }
        }
    }