java - 为什么 DownloadManager.Request "allowScanningByMediaScanner()"在 Android Q 上不起作用？

Question

下面的代码适用于Q以下的任何Android版本。但是当我在Android Q上测试它时，它不起作用。视频文件已下载并可播放。问题出在媒体扫描仪上。

private void downloadVideo(String url, String videoPath) {
        try {
            File file = new File(videoPath);

            DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url))
                    .setTitle(videoType.name() + " Video")
                    .setDescription("")
                    .setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)
                    .setDestinationUri(Uri.fromFile(file))
                    .setAllowedOverMetered(true)
                    .setAllowedOverRoaming(true);

            request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, Uri.fromFile(file).getLastPathSegment());
            request.allowScanningByMediaScanner();

            DownloadManager downloadManager = (DownloadManager) this.getSystemService(Context.DOWNLOAD_SERVICE);
            downloadManager.enqueue(request);

            Toast.makeText(this, "Download started. Check notification bar for progress.", Toast.LENGTH_SHORT).show();
        } catch (Exception ex) {
            ex.printStackTrace();
            Toast.makeText(this, "Unable to download video", Toast.LENGTH_SHORT).show();
        }
    }

Answer 1

这不起作用，因为此方法在 Android Q 中已弃用。

可以在官方文档中找到注释:

Starting in Q, this value is ignored. Files downloaded to directories owned by applications (e.g. Context#getExternalFilesDir(String)) will not be scanned by MediaScanner and the rest will be scanned.

来源:https://developer.android.com/reference/android/app/DownloadManager.Request#allowScanningByMediaScanner()