IOS提醒用户重新授权打开定位功能

func showEventsAcessDeniedAlert() {
  let alertController = UIAlertController(title: "Sad Face Emoji!",
    message: "The calendar permission was not authorized. Please enable it in Settings to continue.",
    preferredStyle: .Alert)
  let settingsAction = UIAlertAction(title: "Settings", style: .Default) { (alertAction) in
    // THIS IS WHERE THE MAGIC HAPPENS!!!!
    if let appSettings = NSURL(string: UIApplicationOpenSettingsURLString) {
      UIApplication.sharedApplication().openURL(appSettings)
    }
  }
  alertController.addAction(settingsAction)
  let cancelAction = UIAlertAction(title: "Cancel", style: .Cancel, handler: nil)
  alertController.addAction(cancelAction)
  presentViewController(alertController, animated: true, completion: nil)
}

if let appSettings = NSURL(string: UIApplicationOpenSettingsURLString) {
  UIApplication.sharedApplication().openURL(appSettings)
}