private val downloadManager by lazy { getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager }
    private var downloadId = 0L

    fun downloadByManager() {
        val downloadRequest = DownloadManager.Request(Uri.parse("https://study.163.com/pub/study-android-official.apk")).apply {
            setAllowedOverRoaming(false)
            setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE)
            setTitle("Download Update")
            setDescription("Download progress running")
            setVisibleInDownloadsUi(true)
            val file = File(getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS), "study163.apk")
            setDestinationUri(Uri.fromFile(file))
        }

        downloadId = downloadManager.enqueue(downloadRequest)
        registerReceiver(downloadReceiver, IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE))
    }

    private val downloadReceiver = object : BroadcastReceiver() {
        override fun onReceive(context: Context, intent: Intent) {
            val query = DownloadManager.Query()
            query.setFilterById(downloadId)
            val cursor = downloadManager.query(query)
            if (!cursor.moveToFirst()) return
            Log.d("--wh--", when (cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS))) {
                DownloadManager.STATUS_PAUSED -> "PAUSED"
                DownloadManager.STATUS_PENDING -> "PENDING"
                DownloadManager.STATUS_RUNNING -> "RUNNING"
                DownloadManager.STATUS_SUCCESSFUL -> "SUCCESSFUL"
                DownloadManager.STATUS_FAILED -> "FAILED"
                else -> "===>"
            })
        }
    }