How to download files from Internet as background, is below code<\/p>\n
Can get completionheader by adding “handleEventsForBackgroundURLSession” at AppDelegate when download completed at background<\/p>\n
in this case, Download progress info is displayed at progress bar<\/p>\n
\r\n\r\n \/\/MARK: BackgroundDownload\r\n private func application(application: UIApplication, handleEventsForBackgroundURLSession identifier: String, completionHandler: @escaping () -> Void) {\r\n \r\n print(\"Background OK\")\r\n completionHandler()\r\n \r\n }\r\n<\/pre>\nviewController.swift<\/h2>\n
Have to setup URLSessionDownloadDelegate<\/p>\n
on didFinishDownloadingTo, run method when download complete.
\nfor instance, move tmp downloaded file to local <\/p>\n
on didWriteData, get download progress info, then update progress bar.<\/p>\n
on didCompleteWithError, call this method in the case of error.<\/p>\n
\r\n\r\n\r\nclass viewContoller: UIViewController,URLSessionDownloadDelegate{\r\n \r\n @IBOutlet var progressBar: UIProgressView!\r\n\r\n \/\/MARK: didload\r\n override func viewDidLoad() {\r\n super.viewDidLoad()\r\n\r\n if let url:NSURL = NSURL(string: \"https:\/\/xxxxxxx\") {\r\n self.startDownload(url: url as URL, id: \"252\", name: \"\u30c6\u30b9\u30c8\")\r\n }\r\n }\r\n\r\n \/\/MARK: Progress Bar\r\n func resetProgress(){\r\n DispatchQueue.main.async {\r\n self.progressBar.isHidden = true\r\n self.progressBar.progress = 0\r\n }\r\n \r\n }\r\n \r\n \/\/Custom fucntion\r\n func startDownload(url : URL, id: String, name: String){\r\n progressBar.isHidden = false\r\n \r\n let session = initSession(delegate:self)\r\n let downloadTask = session.downloadTask(with: url)\r\n downloadTask.taskDescription = \"\\(id),\\(name)\"\r\n downloadTask.resume() \/\/start download\r\n \r\n }\r\n \r\n \r\n \/\/ MARK: - URLSessionDownloadDelegate\r\n \r\n func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {\r\n \r\n print(\"download complete\")\r\n \r\n resetProgress()\r\n \r\n let fileName = downloadTask.originalRequest?.url?.lastPathComponent\r\n let localURL = NSURL(string: \"file:\/\/\"+fileInLibraryDirectory(filename: fileName!))\r\n let info = downloadTask.taskDescription?.components(separatedBy: \",\")\r\n\r\n \/\/save file from tmp to local\r\n do {\r\n try FileManager.default.copyItem(at: location, to: localURL! as URL)\r\n \/\/other method after saving file to local\r\n \r\n } catch (let writeError) {\r\n print(\"error writing file \\(location) : \\(writeError)\")\r\n }\r\n \r\n }\r\n \r\n func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {\r\n \r\n let progress = Float(totalBytesWritten) \/ Float(totalBytesExpectedToWrite)\r\n \r\n print(String(format: \"%.2f\", progress * 100) + \"%\")\r\n \r\n DispatchQueue.main.async {\r\n self.progressBar.setProgress(progress, animated: true)\r\n }\r\n \r\n }\r\n \r\n func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {\r\n if error != nil {\r\n print(\"download error: \\(error)\")\r\n }\r\n \r\n }\r\n\r\n\r\n \/\/MARK:Library folder\r\n func getLibraryURL() -> NSURL {\r\n \r\n let libraryURL = FileManager.default.urls(for: .libraryDirectory, in: .userDomainMask)[0]\r\n \r\n return libraryURL as NSURL\r\n }\r\n\r\n func fileInLibraryDirectory(filename: String) -> String {\r\n let folderName = \"media\"\r\n createDirectory(foldername: folderName)\r\n let fileURL = getLibraryURL().appendingPathComponent(\"\\(folderName)\/\\(filename)\")\r\n return fileURL!.path\r\n \r\n }\r\n\r\n \/\/MARK:Create Directory\r\n func createDirectory(foldername : String){\r\n let fileManager = FileManager.default\r\n let paths = (NSSearchPathForDirectoriesInDomains(.libraryDirectory, .userDomainMask, true)[0] as NSString).appendingPathComponent(foldername)\r\n if !fileManager.fileExists(atPath: paths){\r\n try! fileManager.createDirectory(atPath: paths, withIntermediateDirectories: true, attributes: nil)\r\n }else{\r\n print(\"Already dictionary created.\")\r\n }\r\n }\r\n \r\n}\r\n\r\n\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"How to download file<\/p>\n","protected":false},"author":1,"featured_media":88,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/blue-bear.jp\/kb\/wp-json\/wp\/v2\/posts\/1251"}],"collection":[{"href":"https:\/\/blue-bear.jp\/kb\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blue-bear.jp\/kb\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blue-bear.jp\/kb\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blue-bear.jp\/kb\/wp-json\/wp\/v2\/comments?post=1251"}],"version-history":[{"count":1,"href":"https:\/\/blue-bear.jp\/kb\/wp-json\/wp\/v2\/posts\/1251\/revisions"}],"predecessor-version":[{"id":1252,"href":"https:\/\/blue-bear.jp\/kb\/wp-json\/wp\/v2\/posts\/1251\/revisions\/1252"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blue-bear.jp\/kb\/wp-json\/wp\/v2\/media\/88"}],"wp:attachment":[{"href":"https:\/\/blue-bear.jp\/kb\/wp-json\/wp\/v2\/media?parent=1251"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blue-bear.jp\/kb\/wp-json\/wp\/v2\/categories?post=1251"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blue-bear.jp\/kb\/wp-json\/wp\/v2\/tags?post=1251"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}