ios - NSURLSession 什么时候运行？

Question

我有一种情况，当设备收到推送通知时，我会发送一个 NSURLSession 和一个 NSURLConnection。我有几个关于 NSURLSession 的问题。

如果互联网连接丢失，NSURLSession 的 数据任务是否会在后台自动恢复？

如果最初没有互联网，NSURLSession 会自动尝试完成任务，还是 session 只是返回错误？

Answer 1

看来要由您来处理重试了。

When any task completes, the NSURLSession object calls the delegate’s URLSession:task:didCompleteWithError: method with either an error object, or nil if the task completed successfully. If the task is a resumable download task, the NSError object’s userInfo dictionary contains a value for the NSURLSessionDownloadTaskResumeData key. Your app should use reachability APIs to determine when to retry, and should then call downloadTaskWithResumeData: or downloadTaskWithResumeData:completionHandler: to create a new download task to continue that download. Go to step 3 (creating and resuming task objects).

https://developer.apple.com/library/ios/documentation/cocoa/Conceptual/URLLoadingSystem/NSURLSessionConcepts/NSURLSessionConcepts.html