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前面讲了如何让程序申请后台短时运行。但这个额外延长的时间毕竟有限。所以从iOS7起又引入两种在后台运行任务的方式：后台获取和后台通知。
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import UIKit@UIApplicationMainclass AppDelegate: UIResponder, UIApplicationDelegate { var window: UIWindow? func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { //开启通知 let settings = UIUserNotificationSettings(forTypes: [.Alert, .Badge, .Sound], categories: nil) application.registerUserNotificationSettings(settings) return true } func applicationWillResignActive(application: UIApplication) { } func applicationDidEnterBackground(application: UIApplication) { //虽然定义了后台获取的最短时间，但iOS会自行以它认定的最佳时间来唤醒程序，这个我们无法控制 //UIApplicationBackgroundFetchIntervalMinimum 尽可能频繁的调用我们的Fetch方法 application.setMinimumBackgroundFetchInterval(UIApplicationBackgroundFetchIntervalMinimum) } func applicationWillEnterForeground(application: UIApplication) { } func applicationDidBecomeActive(application: UIApplication) { } func applicationWillTerminate(application: UIApplication) { } //后台获取数据 func application(application: UIApplication, performFetchWithCompletionHandler completionHandler: (UIBackgroundFetchResult) -> Void) { //创建NSURL对象 let url:NSURL! = NSURL(string:"http://api.k780.com:88/?app=life.time&appkey=10003&sign=b59bc3ef6191eb9f747dd4e83c99f2a4&format=json") //创建请求对象 let request:NSURLRequest = NSURLRequest(URL: url) let session = NSURLSession.sharedSession() let dataTask = session.dataTaskWithRequest(request, completionHandler: {(data, response, error) -> Void in if error != nil{ print(error?.code) print(error?.description) //让OS知道获取数据失败 completionHandler(UIBackgroundFetchResult.Failed) }else{ let str = NSString(data: data!, encoding: NSUTF8StringEncoding) print(str) //清除所有本地推送 //UIApplication.sharedApplication().cancelAllLocalNotifications() //创建UILocalNotification来进行本地消息通知 let localNotification = UILocalNotification() //推送时间（立刻推送） localNotification.fireDate = NSDate(timeIntervalSinceNow: 0) //时区 localNotification.timeZone = NSTimeZone.defaultTimeZone() //推送内容 localNotification.alertBody = "获取时间成功：\(str)" //声音 localNotification.soundName = UILocalNotificationDefaultSoundName UIApplication.sharedApplication().scheduleLocalNotification(localNotification) //让OS知道已经获取到新数据 completionHandler(UIBackgroundFetchResult.NewData) //completionHandler(UIBackgroundFetchResult.NoData) } }) as NSURLSessionTask //使用resume方法启动任务 dataTask.resume() }} |
5，后台获取测试
Swift - 后台获取数据（Background Fetch）的实现
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原文地址：http://www.cnblogs.com/Free-Thinker/p/4844889.html
