Android 下载管理器无法在可移动存储设备中运行

如何解决Android 下载管理器无法在可移动存储设备中运行

我正在使用 downloadManager 从服务器下载大文件，我想将这些文件存储在我的可移动存储中，如 SD 卡或 USB（pendrive）。我的下载位置是 /storage/511B-14E9/Media 。我可以在我的可移动存储中成功创建 Media 文件夹。但是下载的文件没有保存在这个位置。

清单中的权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

android:requestLegacyExternalStorage="true"

找到USB的方法

 fun getUSB(): String? {
        val storageDirectory = File("/storage")
        if (!storageDirectory.exists()) {
            Log.e(
                "ZZZZ","getUSB: '/storage' does not exist on this device"
            )
            return ""
        }
        val files = storageDirectory.listFiles()
        if (files == null) {
            Log.e(
                "ZZZZ","getUSB: Null when requesting directories inside '/storage'"
            )
            return ""
        }
        val possibleUSBStorageMounts: ArrayList<String> = ArrayList()
        for (file in files) {
            val path = file.path
            if (path.contains("emulated") ||
                path.contains("sdcard") ||
                path.contains("self")
            ) {
                Log.d("ZZZZ","getUSB: Found '$path' - not USB")
            } else {
                possibleUSBStorageMounts.add(path)
            }
        }
        if (possibleUSBStorageMounts.size == 0) {
            setErrorLog(44,"Did not find any possible USB mounts")
            return ""
        }
        if (possibleUSBStorageMounts.size > 1) {
            Log.d(
                "ZZZZ","getUSB: Found multiple possible USB mount points,choosing the first one"
            )
        }
        isUsbFound = possibleUSBStorageMounts.size != 0
        if (PreferenceManager.getDefaultSharedPreferences(this)
                .getString("pref_usb","") == "" || !possibleUSBStorageMounts.contains(
                PreferenceManager.getDefaultSharedPreferences(this)
                    .getString("pref_usb","")
            )
        ) {

            PreferenceManager.getDefaultSharedPreferences(this)
                .edit()
                .putString("pref_usb",possibleUSBStorageMounts[0])
                .apply()
        } else if (possibleUSBStorageMounts.size > 1) {
            possibleUSBStorageMounts.forEach { usb ->
                if (usb == PreferenceManager.getDefaultSharedPreferences(this)
                        .getString("pref_usb","")
                ) {
                    possibleUSBStorageMounts[0] = usb
                }
            }
        }
        return possibleUSBStorageMounts[0]
    }

下载视频的方法

private fun downloadFromUrl(url : String){

   if (manager == null) {
                manager =
                    getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager
            }

            if (url != "") {
                val request = DownloadManager.Request(Uri.parse(url))
                request.setDescription("")
                request.setTitle("Download")
                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)

 val path = getUSB() + "/"
                        val dir = File(path,"Media")
                        if (!dir.exists()) {
                            dir.mkdir()
                        }

                        val file = File(dir,url.md5() + ".mp4")
                        val uri = Uri.fromFile(file)
                        request.setDestinationUri(uri)
}

我的问题是，是否可以将文件直接下载到可移动存储？ .如果是，情况如何？

注意：现在我可以在 Mi Android TV 中下载文件，但在 Sony Bravia Android TV 中无法下载（访问被拒绝，无法向 USB 写入任何内容）。

提前致谢。