xcode - 警报消息按钮，限制进一步进入下一个 View Controller

Question

您好，我正在使用具有年龄限制的 PickerView 制作 ViewController。我使用了警报和年龄限制，但如果用户年龄不够大，我需要它拒绝访问下一个 ViewController。

像这样制作我的代码，我猜它在Else true中，我需要更多代码，但我不确定。我希望好心人能帮助我:)

@IBAction func verificerKnap(sender: AnyObject) {

    // Creating the age restriction for the datepicker
    let dateOfBirth = datoPicker.date

    let today = NSDate()

    let gregorian = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)!

    let age = gregorian.components([.Year], fromDate: dateOfBirth, toDate: today, options: [])

    if age.year < 18 {

        // Alert controller som sender en advarsel hvis personen er under 18år
        let alertController = UIAlertController(title: "Age restriction", message:
            "This app requires an age of 18+", preferredStyle: UIAlertControllerStyle.Alert)
        alertController.addAction(UIAlertAction(title: "Okay", style: UIAlertActionStyle.Default,handler: nil))

        self.presentViewController(alertController, animated: true, completion: nil)



    } else {

        true

Answer 1

您可以提供一个 UIAlertController，询问您是否年满 18 岁。链接 2 个按钮“确定”和“取消”并为它们添加代表:

let alertController = UIAlertController(title: "Default Style", message: "Are you 18 years or older?", preferredStyle: .Alert)

let cancelAction = UIAlertAction(title: "Cancel", style: .Cancel) { 
    (action) in
    print("User is not yet >18")
}
alertController.addAction(cancelAction)

let OKAction = UIAlertAction(title: "OK", style: .Default) { 
    (action) in
    dispatch_async(dispatch_get_main_queue(), {
        self.presentViewController(desired_view_controller, animated: true, completion: nil)
    })
}
alertController.addAction(OKAction)

self.presentViewController(alertController, animated: true) {
// ...
}

基于:http://nshipster.com/uialertcontroller/