关闭时下载停止 ViewController

Question

我在 Swift 中使用 Cheapjack Library (iOS) 下载我的应用程序中的文件。我从另一个 class 排队下载。这似乎工作正常，下载排队并开始下载。但是，当下载发生的 "DownloadsViewController" 未显示时，当文件完成下载时，它不会执行 didiFinishDownload 块。关于如何处理我的错误的任何想法。此外，当我打开下载 ViewController 并关闭它时，下载挂在我关闭 ViewController 时的位置有什么想法吗？

这是我的代码：

//Adding download from another class
let downloadItem = DownloadsTableViewCellItem(identifier: identifier, urlString: url3, infoLabelTitle: info, stateLabelTitle: "Downloading...", progressLabelTitle: "", action: DownloadsTableViewCellAction.Pause)
        DownloadsViewController().addDownloadItem(downloadItem, withIdentifier: identifier)

//Receiving download in DownloadsViewController
func addDownloadItem(downloadItem: DownloadsTableViewCellItem, withIdentifier identifier: CheapjackFile.Identifier) {

        downloadItems[identifier] = downloadItem
        identifiers.append(identifier)

        CheapjackManager.sharedManager.download(downloadItem.url(), identifier: identifier)
        self.tableView.reloadData()

    }

//DidFinishBlock
func cheapjackManager(manager: CheapjackManager, didFinishDownloading withSession: NSURLSession, downloadTask: NSURLSessionDownloadTask, url: NSURL, forFile file: CheapjackFile) {
        dispatch_async(dispatch_get_main_queue()) {
        print("Did finish downloading file")
        SongsTableViewController().tableView.reloadData()

            let filemanager = NSFileManager.defaultManager()
            let documentsPath : AnyObject = NSSearchPathForDirectoriesInDomains(.DocumentDirectory,.UserDomainMask,true)[0]
            print("DocumentsPath: \(documentsPath)")
        let randomUUID: String = NSUUID().UUIDString + ".mp3"
        let destinationPath = documentsPath.stringByAppendingString("/" + randomUUID)
            print("DestinationPath: \(destinationPath)")


            if (!filemanager.fileExistsAtPath(destinationPath as String)) {

                let url1 = file.request.URL
                print("URL1: \(url1)")
                print("Temp Loc: \(String(url))")

                let data = NSData(contentsOfURL: url)

                if (data != nil) {



                        data!.writeToFile(destinationPath, atomically: false)
                       //data!.writeToURL(NSURL(string:destinationPath)!, atomically: false)

                            print("The music files has been saved.")


                        let appDel: AppDelegate = (UIApplication.sharedApplication().delegate as! AppDelegate)

                        let fetchRequest = NSFetchRequest(entityName: "Track")
                        fetchRequest.predicate = NSPredicate(format: "url = %@", String(url1!))

                        let context = appDel.managedObjectContext

                        do {

                            let results = try context.executeFetchRequest(fetchRequest)

                            fetchResults = results as! [NSManagedObject]

                            if fetchResults.count != 0 {

                                let managedObject = fetchResults[0]
                                managedObject.setValue(destinationPath, forKey: "fileURL")

                                appDel.saveContext()

                                SongsTableViewController().fetchData()

                            } else {

                                print("No track found")
                            }

                        } catch let error as NSError {
                            print("Could not fetch \(error), \(error.userInfo)")
                    }

                }
            } else {
                print("The files already exist")
            }
        }
}

Answer 1

DownloadsViewController 如果您将其关闭，它将被 deinit。

请注意 CheapjackManager 的 delegate 是 weak。关闭 DownloadsViewController 后，delegate 将设置为 nil，对 delegate 的任何调用都将被忽略，包括 cheapjackManager:didiFinishDownload:.

同时，CheapjackManager还在为您下载资源。只是无法在 DownloadsViewController.

中观察到它

关闭时下载停止 ViewController

Download Stops When Dismissing ViewController

ios

nsurlsessiondownloadtask

swift