如何將計時器中的數據傳遞給新的ViewController（Swift 3）

Question

我知道如何將數據傳遞給新的ViewController。問題是我似乎無法從計時器內傳遞數據。

以下代碼適用於一個ViewController。我嘗試了多種方法將代碼拆分爲兩個視圖控制器。我已經嘗試將計時器放在SecondViewController中。我試過只傳遞最初的datePicker。我曾嘗試將函數放入函數中。

目前的問題是我無法傳遞totalSeconds，因爲它是在定時器內定義的。如果我初始化定時器之外的函數，比如說0，它只是返回一個值0.如果我通過datePicker或date組件，當我在SecondViewController中定義時間間隔時遇到類似的問題。例如，updateTimer函數不會識別傳遞給SecondViewController的ViewDidLoad（）的值。

任何幫助，非常感謝。我只想將字符串放在SecondViewController中的updateTimer（）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 , 

你知道的協議&代表的概念。 您可以使用代理&協議輕鬆解決上述問題。

1.創建在第一類的ViewController一個協議作爲

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

2.創建變量委託作爲

var delegate : TimerUpdateDelegate? 

3.Now添加下面的代碼行中的updateTimer方法第一視圖控制器。

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

在代碼totalSeconds將在自updateTimer功能作爲參數的計算出的值以上的線。

4.Now進口委託在第二的ViewController類作爲，

  class ViewController: UIViewController,TimerUpdateDelegate {} 

5.In viewDidLoad方法添加下面一組線：

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

6.Define TimerUpdateDelegate方法在你的第二類視圖控制器：

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

我希望這會解決您的問題。