ios - 快速文本标签每周更新

Question

我是for swift的初学者。

在 homeviewController 中，我声明了一个标签

    @IBOutlet weak var text: UILabel!

如何从应用安装之日起每周将此数字从 0 更新为 1？

Answer 1

首先，将启动日期存储在应用首次启动时的某处，例如 NSUserDefaults:NSUserDefaults.standardUserDefaults().setObject(NSDate(), forKey: "installDate")。然后，每当您需要显示标签时，只需找到当前时间和存储时间之间的周差即可:

let installDate = NSUserDefaults.standardUserDefaults().objectForKey("installDate") as NSDate!
let today = NSDate()
let calendar = NSCalendar.currentCalendar()
let unitFlags = NSCalendarUnit.WeekOfYear
let dateComponents = calendar.components(unitFlags, fromDate:installDate,  toDate:today, options: NSCalendarOptions.MatchNextTime)
let weeks = dateComponents.weekOfYear