public PlayDownloadFactory(object parameter)
{
_downloadInfo = parameter as DownloadInfo;
}
/// <summary>
/// 开始下载一个新任务，此方法为后台线程调用
/// </summary>
/// <param name="info"></param>
protected async void StartOneDownload(DownloadInfo info)
{
try
{
_isDownloading = true;
var folder = await GetDownloadFolder();
var destinationFile = await folder.
CreateFileAsync(info.LocalFileName, CreationCollisionOption.ReplaceExisting);
info.LocalFileName = destinationFile.Name;
var downloader = new BackgroundDownloader();
var download = downloader.CreateDownload(new Uri(info.DownloadUri), destinationFile);
info.DownloadGuid = download.Guid;
await HandleDownloadAsync(download, info, true);
}
catch (Exception ex)
{
_isDownloading = false;
DownloadFailture(info, ex.Message);
}
}
private void downloadBar_Click(object sender, RoutedEventArgs e)
{
try
{
if (PersonalFactory.Instance.Logined)
{
var downinfos = new List<DownloadInfo>(_downloadList.Count);
foreach (var downInfo in _downloadList)
{
var index = ChannelUtils.CreateProgramIndex(downInfo.Index, _dataSource);
downInfo.IsSelected = false;
downInfo.IsDownloading = true;
var down = new DownloadInfo()
{
TypeId = _dataSource.Type,
ParentId = _dataSource.Id,
ParentName = _dataSource.Title,
ProgramIndex = downInfo.Index,
ChannelId = downInfo.ChannelId,
ImageUri = _dataSource.ImageUri,
DownloadState = DownloadState.Await,
Title = ChannelUtils.CreateChannelTitle(index, _dataSource, false)
};
down.LocalFileName = string.Format("{0}.mp4", down.Title);
downinfos.Add(down);
}
DownloadViewModel.Instance.AddDownloads(downinfos);
if (_downloadList.Count > 0)
TileUtils.CreateToastNotifications("已加入下载，请到个人中心查看");
_downloadList.Clear();
downloadBar.Visibility = Visibility.Collapsed;
}
else
{
TileUtils.CreateToastNotifications("请先至个人中心登录");
}
bottomBar.IsOpen = false;
}
catch
{
TileUtils.CreateToastNotifications("加入下载失败");
}
}
protected abstract void DownloadProgress(DownloadOperation download, DownloadInfo info);
protected abstract void DownloadFailture(DownloadInfo info, string errMessage);
protected abstract void DownloadCompleted(DownloadInfo info);
private async Task HandleDownloadAsync(DownloadOperation download, DownloadInfo info, bool start)
{
try
{
_activeDownloads[info.ChannelId] = download;
_cts[info.ChannelId] = new CancellationTokenSource();
var progressCallback = new Progress<DownloadOperation>(downOperation =>
{
DownloadProgress(downOperation, info);
});
if (start)
{
await download.StartAsync().AsTask(_cts[info.ChannelId].Token, progressCallback);
}
else
{
await download.AttachAsync().AsTask(_cts[info.ChannelId].Token, progressCallback);
}
_activeDownloads.Remove(info.ChannelId);
_cts.Remove(info.ChannelId);
var response = download.GetResponseInformation();
_isDownloading = false;
DownloadCompleted(info);
}
catch (System.Threading.Tasks.TaskCanceledException) { }
catch (Exception ex)
{
_isDownloading = false;
DownloadFailture(info, ex.Message);
}
}
protected void CancelDownload(DownloadInfo info)
{
if (_cts.ContainsKey(info.ChannelId))
{
_cts[info.ChannelId].Cancel();
_cts[info.ChannelId].Dispose();
}
_cts.Remove(info.ChannelId);
}
/// <summary>
/// 继续一个下载任务
/// </summary>
/// <param name="info"></param>
protected bool ResumeOneDownload(DownloadInfo info)
{
if (_activeDownloads.ContainsKey(info.ChannelId)
&& _activeDownloads[info.ChannelId].Progress.Status == BackgroundTransferStatus.PausedByApplication)
{
_isDownloading = true;
_activeDownloads[info.ChannelId].Resume();
info.DownloadState = DownloadState.Downloading;
return true;
}
return false;
}
/// <summary>
/// 暂停一个下载任务
/// </summary>
/// <param name="info"></param>
protected void PauseOneDownload(DownloadInfo info)
{
if (_activeDownloads.ContainsKey(info.ChannelId)
&& (_activeDownloads[info.ChannelId].Progress.Status == BackgroundTransferStatus.Running
|| _activeDownloads[info.ChannelId].Progress.Status == BackgroundTransferStatus.PausedNoNetwork
|| _activeDownloads[info.ChannelId].Progress.Status == BackgroundTransferStatus.PausedCostedNetwork)
)
{
_activeDownloads[info.ChannelId].Pause();
info.DownloadState = DownloadState.Pause;
}
}
