How to directly download a file to Download directory on Android Q (Android 10)

Question

Lets say I\'m developing a chat app that is able to share with others ANY kind of files (no mimetype restriction): like images, videos, documents, but also compressed files like

Answer 1

More than 10 months have passed and yet not a satisfying answer for me have been made. So I'll answer my own question.

As @CommonsWare states in a comment, "get MediaStore.Downloads.INTERNAL_CONTENT_URI or MediaStore.Downloads.EXTERNAL_CONTENT_URI and save a file by using Context.getContentResolver.insert()" is supposed to be the solution. I double checked and found out this is true and I was wrong saying it doesn't work. But...

I found it tricky to use ContentResolver and I was unable to make it work properly. I'll make a separate question with it but I kept investigating and found a somehow satisfying solution.

MY SOLUTION:

Basically you have to download to any directory owned by your app and then copy to Downloads folder.

1. Configure your app:

   • Add provider_paths.xml to xml resource folder

   • In your manifest add a FileProvider:

2. Prepare to download files to any directory your app owns, such as getFilesDir(), getExternalFilesDir(), getCacheDir() or getExternalCacheDir().

   val privateDir = context.getFilesDir()
   

3. Download file taking its progress into account (DIY):

   val downloadedFile = myFancyMethodToDownloadToAnyDir(url, privateDir, fileName)
   

4. Once downloaded you can make any threatment to the file if you'd like to.

5. Copy it to Downloads folder:

   //This will be used only on android P-
   private val DOWNLOAD_DIR = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)
   
   val finalUri : Uri? = copyFileToDownloads(context, downloadedFile)
   
   fun copyFileToDownloads(context: Context, downloadedFile: File): Uri? {
       val resolver = context.contentResolver
       return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
           val contentValues = ContentValues().apply {
               put(MediaStore.MediaColumns.DISPLAY_NAME, getName(downloadedFile))
               put(MediaStore.MediaColumns.MIME_TYPE, getMimeType(downloadedFile))
               put(MediaStore.MediaColumns.SIZE, getFileSize(downloadedFile))
           }
           resolver.insert(MediaStore.Downloads.EXTERNAL_CONTENT_URI, contentValues)
       } else {
           val authority = "${context.packageName}.provider"
           val destinyFile = File(DOWNLOAD_DIR, getName(downloadedFile))
           FileProvider.getUriForFile(context, authority, destinyFile)
       }?.also { downloadedUri ->
           resolver.openOutputStream(downloadedUri).use { outputStream ->
               val brr = ByteArray(1024)
               var len: Int
               val bufferedInputStream = BufferedInputStream(FileInputStream(downloadedFile.absoluteFile))
               while ((bufferedInputStream.read(brr, 0, brr.size).also { len = it }) != -1) {
                   outputStream?.write(brr, 0, len)
               }
               outputStream?.flush()
               bufferedInputStream.close()
           }
       }
   }
   

6. Once in download folder you can open file from app like this:

   val authority = "${context.packageName}.provider"
   val intent = Intent(Intent.ACTION_VIEW).apply {
       setDataAndType(finalUri, getMimeTypeForUri(finalUri))
       if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.LOLLIPOP) {
           addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION or Intent.FLAG_GRANT_READ_URI_PERMISSION)
       } else {
           addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
       }
   }
   try {
       context.startActivity(Intent.createChooser(intent, chooseAppToOpenWith))
   } catch (e: Exception) {
       Toast.makeText(context, "Error opening file", Toast.LENGTH_LONG).show()
   }
   
   //Kitkat or above
   fun getMimeTypeForUri(context: Context, finalUri: Uri) : String =
       DocumentFile.fromSingleUri(context, finalUri)?.type ?: "application/octet-stream"
   
   //Just in case this is for Android 4.3 or below
   fun getMimeTypeForFile(finalFile: File) : String =
       DocumentFile.fromFile(it)?.type ?: "application/octet-stream"
   

Pros:

• Downloaded files survives to app uninstallation

• Also allows you to know its progress while downloading

• You still can open them from your app once moved, as the file still belongs to your app.

• write_external_storage permission is not required for Android Q+, just for this purpose:

Cons:

• You won't have access to downloaded files once after clearing your app data or uninstalling and reinstalling again (they no longer belongs to your app unless you ask for permission)
• Device must have more free space to be able to copy every file from its original directory to its final destination. This is important speacially for large files. Although if you have access to the original inputStream you could directly write to downloadedUri instead of copying from an intermediary file.

If this approach is enough for you then give it a try.