iOS8:不推荐使用backgroundSessionConfiguration

Question

在iOS8发布之前,我下载了iOS8 SDK来观看我的应用程序是如何工作的.有时我的应用程序需要从服务器下载数据,我使用NSUrlSession.现在,当app准备下载会话时,出现下一个警告:

+backgroundSessionConfiguration: is deprecated. Please use +backgroundSessionConfigurationWithIdentifier: instead.

之后我的应用程序崩溃了下一个异常:

Unable to cast object of type 'MonoTouch.Foundation.NSUrlSessionTask' (Objective-C type: '__NSCFBackgroundDownloadTask') to type 'MonoTouch.Foundation.NSUrlSessionDownloadTask'.
Additional information:
    Selector: URLSession:downloadTask:didFinishDownloadingToURL:
    Method: Microsoft.Synchronization.ClientServices.NSUrlDownloadDelegate:DidFinishDownloading (MonoTouch.Foundation.NSUrlSession,MonoTouch.Foundation.NSUrlSessionDownloadTask,MonoTouch.Foundation.NSUrl)

创建NSUrlSession的代码:

NSUrlSessionConfiguration sessionConfiguration = NSUrlSessionConfiguration.BackgroundSessionConfiguration(urlSessioinId);
NSUrlDownloadDelegate downloadDelegate = new NSUrlDownloadDelegate();
NSUrlSession downloadSession = NSUrlSession.FromConfiguration(sessionConfiguration, downloadDelegate, new NSOperationQueue());

谢谢你的帮助!

Answer 1

我在Objective-C中使用以下来解决这个错误:

NSURLSessionConfiguration *sessionConfig;

if ([[[UIDevice currentDevice] systemVersion] floatValue] >=8.0f)
{
    sessionConfig =[NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:@"downloads"];
}
else
{
    sessionConfig = [NSURLSessionConfiguration backgroundSessionConfiguration:@"downloads"];
}

Answer 2

这应该工作.

if(UIDevice.CurrentDevice.CheckSystemVersion(8, 0))
{
 configDownload = NSUrlSessionConfiguration.CreateBackgroundSessionConfiguration(sessionId);
}
else
{
configDownload = NSUrlSessionConfiguration.BackgroundSessionConfiguration(sessionId);
}