在Android 11中,应用程序不再具有对设备文件系统的直接访问权限。由于此更改,将文件下载到下载目录可能不起作用。要解决此问题,请使用以下代码示例将文件下载到应用程序私有目录中,然后使用MediaStore API将其添加到下载管理器中。
首先,添加WRITE_EXTERNAL_STORAGE和MANAGE_EXTERNAL_STORAGE权限到AndroidManifest.xml文件中。
然后,使用以下代码示例将文件下载到应用程序私有目录中:
val url = "your file download url"
val request = DownloadManager.Request(Uri.parse(url))
.setTitle("File Name")
.setDescription("Downloading")
.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)
.setAllowedOverMetered(true)
.setAllowedOverRoaming(true)
.setDestinationUri(Uri.fromFile(File(applicationContext.filesDir, "fileName.txt")))
val downloadManager = getSystemService(DOWNLOAD_SERVICE) as DownloadManager
val downloadId = downloadManager.enqueue(request)
最后,使用以下代码示例将文件添加到下载管理器中:
val uri = FileProvider.getUriForFile(
applicationContext,
"${applicationContext.packageName}.provider",
File(applicationContext.filesDir, "fileName.txt")
)
val values = ContentValues().apply {
put(MediaStore.Downloads.DISPLAY_NAME, "File Name")
put(MediaStore.Downloads.MIME_TYPE, "application/octet-stream")
put(MediaStore.Downloads.RELATIVE_PATH, Environment.DIRECTORY_DOWNLOADS)
put(MediaStore.Downloads.IS_PENDING, 1)
}
val contentResolver = applicationContext.contentResolver
val uriWithPendingUpdate = contentResolver.insert(MediaStore.Downloads.EXTERNAL_CONTENT_URI, values)
val downloadOutputStream = contentResolver.openOutputStream(uriWithPendingUpdate!!)
val downloadInputStream = applicationContext.openFileInput("fileName.txt")
downloadInputStream.copyTo(downloadOutputStream)
downloadInputStream.close()
downloadOutputStream.close()
values.clear()
values.put(MediaStore.Downloads.IS_PENDING, 0)
contentResolver.update(uriWithPendingUpdate, values, null, null)
这将下载文件到应用程序私有目录中,并使用MediaStore API