Question

我知道如何将数据传递给新的ViewController。问题是我似乎无法从计时器中传递数据。

以下代码适用于一个ViewController。我尝试了多种方法将代码分成两个视图控制器。我已经尝试将计时器放在SecondViewController中。我试过只传递初始的datePicker。我试过在函数中放置函数。

目前的问题是我无法通过totalSeconds，因为它是在定时器中定义的。如果我在计时器之外初始化函数，比如说0，它只返回一个值0.如果我传递datePicker或日期组件，我在SecondViewController中定义时间间隔时会遇到类似的问题。例如，updateTimer函数将无法识别传递给SecondViewController的ViewDidLoad（）的值。

非常感谢任何帮助。我只想将updateTimer（）中的字符串放在SecondViewController中。

    class ViewController: UIViewController {

    @IBOutlet weak var datePicker: UIDatePicker!
    @IBOutlet weak var Output: UILabel!
    @IBOutlet weak var Output4: UILabel!
    @IBOutlet weak var Output3: UILabel!
    @IBOutlet weak var Output2: UILabel!
    @IBOutlet weak var timePicker: UIDatePicker!
    @IBOutlet weak var Output5: UILabel!
    @IBOutlet weak var Output6: UILabel!

    var birthDate = DateComponents()

    @IBAction func timePickerChanged(_ sender: Any) {

    let tComponents = Calendar.current.dateComponents([.hour, .minute], from: (sender as AnyObject).date)
    birthDate.hour = tComponents.hour
    birthDate.minute = tComponents.minute
}

    @IBAction func datePickerChanged(_ sender: Any) {
    let components = Calendar.current.dateComponents([.year, .month, .day], from: (sender as AnyObject).date)
    birthDate.year = components.year
    birthDate.month = components.month
    birthDate.day = components.day
}

    override func viewDidLoad() {
    super.viewDidLoad()

    Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(ViewController.updateTimer), userInfo: nil, repeats: true)

    // Do any additional setup after loading the view, typically from a nib.
}

    func updateTimer(){
    let now = Date()

    let birthDay = userCalendar.date(from: birthDate)!

    let totalSeconds = Int(now.timeIntervalSince(birthDay))

    let totalMinutes = userCalendar.dateComponents([.minute], from: birthDay, to: now)

    let totalHours = userCalendar.dateComponents([.hour], from: birthDay, to: now)

    let totalDays = userCalendar.dateComponents([.day], from: birthDay, to: now)

    let totalWeeks = userCalendar.dateComponents([.weekOfYear],from: birthDay, to: now)

    let totalMonths = userCalendar.dateComponents([.month], from: birthDay, to: now)

    Output.text = String(totalSeconds)
    if totalMinutes.minute != nil {
        Output2.text = String(totalMinutes.minute!)
    }
    if totalHours.hour != nil {
        Output3.text = String(totalHours.hour!)
    }
    if totalDays.day != nil{
        Output4.text = String(totalDays.day!)
    }
    if totalWeeks.weekOfYear != nil{
        Output5.text = String(totalWeeks.weekOfYear!)
    }
    if totalMonths.month != nil{
        Output6.text = String(totalMonths.month!)
    }

}
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    updateTimer()
    let secondsController = segue.destination as! SecondViewController
    secondsController.finalSeconds = totalSeconds
}

Answer 1

@CJW ,

您是否了解协议＆amp;代表概念。您可以使用代理人员轻松解决上述问题。协议

1.在第一个viewcontroller类中创建一个协议

protocol TimerUpdateDelegate {
    func updateTotalSeconds(_ iTotalSeconds : Int)
}

2.为委托创建

的变量

var delegate : TimerUpdateDelegate?

3.现在在第一个视图控制器的updateTimer方法中添加以下代码行。

        if self.delegate != nil 
         {self.delegate?.updateTotalSeconds(totalSeconds)}

在上面的代码行中，totalSeconds将是自我updateTimer函数中的计算值作为参数。

4.现在第二个viewcontroller类中的导入委托为

         class ViewController: UIViewController,TimerUpdateDelegate {}

5.在ViewDidload方法中添加以下行集：

override func viewDidLoad() {
  firstViewController.delegate = self
  }

6.在第二个类视图控制器中定义TimerUpdateDelegate方法：

    func updateTotalSeconds(_ iTotalSeconds : Int)
            {
                self.finalSeconds = iTotalSeconds
            }

我希望这能解决你的问题。

如何将计时器中的数据传递给新的ViewController（Swift 3）

1 个答案: