How to download PDF file in selected Dir?

Question

I am trying to download PDF file from the web (url) in selected dir. I am using the below to open the dir picker

  val directoryPickerLauncher = rememberLauncherForActivityResult(
        contract = ActivityResultContracts.OpenDocumentTree()
    ) { uri ->
        selectedDirectoryUri = uri

    }

and once the dir is selected I am downloading the pdf.

       fun downloadPdf(context: Context, pdfUrl: String, pdfTitle: String, directoryUri: Uri?) {
        val downloadManager = context.getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager

        val request = DownloadManager.Request(Uri.parse(pdfUrl))
            .setTitle(pdfTitle)
            .setMimeType("application/pdf")
            .setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)

        // Set the destination directory to the selected directory URI
        if (directoryUri != null) {
            val directory = DocumentFile.fromTreeUri(context, directoryUri)
            if (directory != null && directory.exists() && directory.isDirectory) {
                request.setDestinationInExternalPublicDir(
                    directoryUri.toString(),
                    pdfTitle
                )
            }
        }

        val downloadId = downloadManager.enqueue(request)

        // Store download status for observing in the Composable
        _downloadStatus.value = DownloadStatus(downloadId)
    }

The download manager completed the download and sends me a notification from where I can open the pdf but its not saved in the selected dir.

Answer 1

request.setDestinationInExternalPublicDir() has two parameters. The first one a folder name of a public dir the second one a file name.

It makes little sense to let the user choose a directory if you cannot decode a folder name from the uri.

You better determine the public dir yourself.

Or let it choose from a public dir list.

You should also realise that the user could choose DCIM or Pictures directory. But in both .pdf files cannot be saved.