Swift how to use NSTimer background?
问题 class ViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() var timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("update"), userInfo: nil, repeats: true) } func update() { println("Something cool") } } It's ok for the Simulator ,I will get continuous "Something cool" through I tapped the home button. But it worked out when I debug the app with my iPhone. I did't get anything when I tapped the home button and make my app run