android - 如何从Android中的URL下载文件？

从url下载文件的最佳方法是什么。我尝试使用DownloadManager。但是我不明白如何获取下载文件的Uri。这是我的代码:

   file?.let {
            val uri = Uri.parse(it)
            val downloadManager = getSystemService<Any>(Context.DOWNLOAD_SERVICE) as DownloadManager?
            val request = DownloadManager.Request(uri)
            request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI or
                    DownloadManager.Request.NETWORK_MOBILE)
            request.allowScanningByMediaScanner()
            request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)
            request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "downloadfileName")
            request.setMimeType("*/*")
            downloadManager?.enqueue(request)
        }

也许今天有一种更好的方法来下载文件并获取Uri。请帮我

最佳答案

fun downloadPdf(baseActivity:Context,url: String?,title: String?): Long {
        val direct = File(Environment.getExternalStorageDirectory().toString() + "/your_folder")

        if (!direct.exists()) {
            direct.mkdirs()
        }
        val extension = url?.substring(url.lastIndexOf("."))
        val downloadReference: Long
         var  dm: DownloadManager
         dm= baseActivity.getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager
        val uri = Uri.parse(url)
        val request = DownloadManager.Request(uri)
        request.setDestinationInExternalPublicDir(
                "/your_folder",
                "pdf" + System.currentTimeMillis() + extension
        )
        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)
        request.setTitle(title)
        Toast.makeText(baseActivity, "start Downloading..", Toast.LENGTH_SHORT).show()

        downloadReference = dm?.enqueue(request) ?: 0

        return downloadReference

    }

在调用此方法之前，请检查运行时权限:

Manifest.permission.WRITE_EXTERNAL_STORAGE