使用Cross Download Manager-但找不到文件

Question

我正在尝试使用CrossDownloadManager将文件下载到iOS，但是在任何地方都找不到该文件！经过调试，我发现它可以识别HTTP并“下载”该文件，但是找不到该文件。

我正在使用Ipad ios11。

我不知道是否有更简单的方法，但是这个插件似乎更可行。

我的代码：

CrossDownloadManager.Current.CollectionChanged += (sender, e) =>
            System.Diagnostics.Debug.WriteLine(
                "[DownloadManager] " + e.Action +
                " -> New items: " + (e.NewItems?.Count ?? 0) +
                " at " + e.NewStartingIndex +
                " || Old items: " + (e.OldItems?.Count ?? 0) +
                " at " + e.OldStartingIndex
            );

        var Url2 = "https://mysite/myfile.pdf"; //here i put my file, its ok.

        DownloadFile(Url2);

    }

    public async void DownloadFile(String fileName)
    {
        await Task.Yield();
        //await Navigation.PushPopupAsync(new DownloadingPage());
        await Task.Run(() =>
        {
            var downloadManager = CrossDownloadManager.Current;
            var file = downloadManager.CreateDownloadFile(fileName);
            downloadManager.Start(file, true);

            while (isDownloading)
            {
                isDownloading = IsDownloading(file);
            }
        });

        //await Navigation.PopAllPopupAsync();
        if (!isDownloading)
        {
            await DisplayAlert("File Status", "File Donwload","OK");
            //DependencyService.Get<IToast>().ShowToast(“Baixou”);
        }

    }

    public bool IsDownloading(IDownloadFile file)
    {
        if (file == null) return false;

        switch (file.Status)
        {
            case DownloadFileStatus.INITIALIZED:
            case DownloadFileStatus.PAUSED:
            case DownloadFileStatus.PENDING:
            case DownloadFileStatus.RUNNING:
                return true;

            case DownloadFileStatus.COMPLETED:
            case DownloadFileStatus.CANCELED:
            case DownloadFileStatus.FAILED:
                return false;
            default:
                throw new ArgumentOutOfRangeException();
        }
    }

    public void AbortDownloading()
    {

        CrossDownloadManager.Current.Abort(File);
    }

在iOS部分中，我输入：

public override bool FinishedLaunching(UIApplication app, NSDictionary options)
        {
            global::Xamarin.Forms.Forms.Init();
            LoadApplication(new App());
            Downloaded();
            return base.FinishedLaunching(app, options);
        }

        public void Downloaded()
        {

            CrossDownloadManager.Current.PathNameForDownloadedFile = new System.Func<IDownloadFile, string>
        (file => {

            string fileName = (new NSUrl(file.Url, false)).LastPathComponent;

            System.Diagnostics.Debug.WriteLine(Environment.SpecialFolder.Resources);
            return Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Resources), fileName);
        });
        }


        public override void HandleEventsForBackgroundUrl(UIApplication application, string sessionIdentifier, Action completionHandler)
        {
            CrossDownloadManager.BackgroundSessionCompletionHandler = completionHandler;
        }

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