Android 将文件从webview下载到内部存储器

下面的代码可以完美地将mp3文件下载到外部存储器中，但无法将文件下载到内部存储器中。很多智能手机都没有外部存储器。我能做什么？如果需要的话，我不知道如何在kotlin中实现异步任务

 mywebView.setDownloadListener(object : DownloadListener {
        override fun onDownloadStart(url: String, userAgent: String,
                                     contentDisposition: String, mimetype: String,
                                     contentLength: Long) {


            val request = DownloadManager.Request(Uri.parse(url))
            request.allowScanningByMediaScanner()
            request.setDescription("Download file...")
            request.setTitle(URLUtil.guessFileName(url, contentDisposition, mimetype))

            request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI or DownloadManager.Request.NETWORK_MOBILE)
            request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED) //Notify client once download is completed!
            request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, mimetype )
            val webview = getSystemService(DOWNLOAD_SERVICE) as DownloadManager
            webview.enqueue(request)

            Toast.makeText(getApplicationContext(), "Download avviato", Toast.LENGTH_LONG).show()

        }
    })

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目前无法测试代码，但应该如下所示：

 mywebView.setDownloadListener(object : DownloadListener {
        override fun onDownloadStart(url: String, userAgent: String,
                                     contentDisposition: String, mimetype: String,
                                     contentLength: Long) {


            val request = DownloadManager.Request(Uri.parse(url))
            request.allowScanningByMediaScanner()
            request.setDescription("Download file...")
            request.setTitle(URLUtil.guessFileName(url, contentDisposition, mimetype))

            request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI or DownloadManager.Request.NETWORK_MOBILE)
            request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED) //Notify client once download is completed!
            request.setDestinationInExternalPublicDir(Environment.getExternalStorageDirectory(), mimetype )
            val webview = getSystemService(DOWNLOAD_SERVICE) as DownloadManager
            webview.enqueue(request)

            Toast.makeText(getApplicationContext(), "Download avviato", Toast.LENGTH_LONG).show()

        }
    })

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读和读。因此，所有智能手机都有外部存储，而不是所有智能手机都有SD卡。他要求的是内部存储，而不是外部存储