File is corrupted showing when open it from intent after download by download Manager android

In this feature, I download the file from the URL and after completing the download I open that file from intent but it shows the file is corrupted and not open

here is my code for downloading the file and opening the file from intent

fun downloadFile(activity: Activity, url: String?, fileName: String?) {
        try {
            if (url != null && !url.isEmpty()) {
                val uri: Uri = Uri.parse(url)
                activity.registerReceiver(
                    attachmentDownloadCompleteReceive, IntentFilter(
                        DownloadManager.ACTION_DOWNLOAD_COMPLETE
                    )
                )
                val request: DownloadManager.Request = DownloadManager.Request(uri)
                request.setMimeType(getMimeType(uri.toString()))
                request.setTitle(fileName)
                request.setDescription("Downloading attachment..")
                request.allowScanningByMediaScanner()
                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)
                request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName)
                val dm: DownloadManager =
                    getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager
                dm.enqueue(request)
            }
        } catch (e: IllegalStateException) {
            Toast.makeText(
                activity,
                "Please insert an SD card to download file",
                Toast.LENGTH_SHORT
            ).show()
        }
    }


    private fun getMimeType(url: String): String? {
        var type: String? = null
        val extension: String = MimeTypeMap.getFileExtensionFromUrl(url)
        if (extension != null) {
            val mime: MimeTypeMap = MimeTypeMap.getSingleton()
            type = mime.getMimeTypeFromExtension(extension)
        }
        return type
    }

    var attachmentDownloadCompleteReceive: BroadcastReceiver = object : BroadcastReceiver() {
        override fun onReceive(context: Context, intent: Intent) {
            val action = intent.action
            if (DownloadManager.ACTION_DOWNLOAD_COMPLETE == action) {
                val downloadId = intent.getLongExtra(
                    DownloadManager.EXTRA_DOWNLOAD_ID, 0
                )
                
                openDownloadedAttachment(context, downloadId)
            }
          
        }
    }

    private fun openDownloadedAttachment(context: Context, downloadId: Long) {
        val downloadManager: DownloadManager =
            context.getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager
        val query: DownloadManager.Query = DownloadManager.Query()
        query.setFilterById(downloadId)
        val cursor: Cursor = downloadManager.query(query)
        if (cursor.moveToFirst()) {
            
            val downloadStatus: Int =
                cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS))
            val downloadLocalUri: String =
                cursor.getString(cursor.getColumnIndex(DownloadManager.COLUMN_LOCAL_URI))
            val downloadMimeType: String =
                cursor.getString(cursor.getColumnIndex(DownloadManager.COLUMN_MEDIA_TYPE))
            if (downloadStatus == DownloadManager.STATUS_SUCCESSFUL && downloadLocalUri != null) {
               
                openDownloadedAttachment(context, Uri.parse(downloadLocalUri), downloadMimeType)
            }
        }
        
        cursor.close()
    }

    private fun openDownloadedAttachment(
        context: Context,
        attachmentUri: Uri,
        attachmentMimeType: String
    ) {
        var attachmentUri: Uri? = attachmentUri
        if (attachmentUri != null) {
           
            // Get Content Uri.
            if (ContentResolver.SCHEME_FILE == attachmentUri.scheme) {
                // FileUri - Convert it to contentUri.
                val file = File(attachmentUri.path)
                attachmentUri =
                    FileProvider.getUriForFile(
                        this,
                        BuildConfig.APPLICATION_ID + ".fileprovider",
                        file
                    )
            }
           
            val openAttachmentIntent = Intent(Intent.ACTION_VIEW)
            openAttachmentIntent.setDataAndType(attachmentUri, attachmentMimeType)
            openAttachmentIntent.flags = Intent.FLAG_GRANT_READ_URI_PERMISSION
            try {
               
                this.startActivity(openAttachmentIntent)
            } catch (e: ActivityNotFoundException) {
               
                Toast.makeText(
                    this,
                    "false",
                    Toast.LENGTH_LONG
                ).show()
            }
        }
    }

So can tell me where I made mistake on this, why it shows the file is corrupted after downloading it and I check that file by opening it from the file manager and it's working fine.

You should get a content scheme from download manager instead of that file scheme.

Try:

   Uri downloadmanageruri = ( (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE))
                      .getUriForDownloadedFile(downloadId); 

That should be a content scheme and you would not need FileProvider. `