不能從一個函數傳遞一個變量到另一個功能斯威夫特

Question

我問大約一個星期前這個問題的一部分，並得到否決了，所以我花了時間它正在努力解決它。我已經研究過如何完成在UIPicker和函數之間傳遞的第一部分。我創建了一個類calculateTime（），裏面是我的函數，它接受一個數組作爲參數。然後計算一個我標籤計數的數字。 接下來我需要做的是通過update（）函數的計數，以便我可以使用倒數計時器更新文本標籤。無論我把這個功能放在哪裏，我都無法讓它工作。如果它在課堂內部，我會得到一個選擇器錯誤。如果它在課外，我無法獲得數值。它會被我在代碼頂部設置的值覆蓋。我在這裏粘貼所有的代碼。我希望有人能夠幫助我，我對自己無法解決這個問題感到沮喪。

import UIKit 
import MapKit 
import CoreLocation 

class ViewController: UIViewController, UIPickerViewDelegate,  UIPickerViewDataSource, UITextFieldDelegate { 

@IBOutlet weak var dep: UITextField! 

@IBOutlet weak var picker: UIPickerView! 

@IBOutlet weak var arrivesAt: UIButton! 

@IBOutlet weak var departsFrom: UIButton! 

@IBOutlet weak var arr: UITextField! 

@IBOutlet weak var countDownLabel: UILabel! 



var pickerData: [[String]] = [[String]]() 

var timer: NSTimer! 

var count = 2 

var arrayTimes = [""] 


override func viewDidLoad() { 
    super.viewDidLoad() 


    calculateTime().refreshView(["5:45", "6:35", "7:00", "7:30", "7:50", "8:20", "8:40", "9:15", "10:10", "11:10", "12:40", "14:15", "14:50", "15:40", "16:10", "17:10", "17:40", "18:40", "19:25", "20:50"]) 

    picker.hidden = true 

    dep.delegate = self 

    dep.resignFirstResponder() 
    arr.resignFirstResponder() 

    //Picker 

    // Connect data: 
    self.picker.delegate = self 
    self.picker.dataSource = self 


    // Input data into the Array: 
    pickerData = [["larkspur", "saulsalito", "san francisco", "fisherman's wharf", "giants stadium", "tiburon", "vallejo", "alameda", "harbor bay", "jack london", "south s.f."], 
     ["san francisco", "saulsalito", "larkspur", "fisherman's wharf", "giants stadium", "tiburon", "vallejo", "alameda", "harbor bay", "jack london", "south s.f."]] 

} 



//Mark - Location Delegate Methods 



struct MyViewState { 
    static var count = 8 
} 



class calculateTime { 

    var timesArray:[String] = [] 

    var timer: NSTimer! 

    var count: Int = 0 

    func refreshView(array: [String]) { 


     let date = NSDate() 
     let calendar = NSCalendar.currentCalendar() 
     let components = calendar.components([.Hour, .Minute], fromDate: date) 
     let hour = components.hour 
     let minutes = components.minute 
     let currentTime = "\(hour)" + ":" + "\(minutes)" 

     self.timesArray = array 

     print(timesArray) 

     // create a method to convert your time to minutes 
     func stringToMinutes(input:String) -> Int { 
      let components = input.componentsSeparatedByString(":") 
      let hour = Int((components.first ?? "0")) ?? 0 
      let minute = Int((components.last ?? "0")) ?? 0 
      return hour*60 + minute 
     } 

     //create an array with the minutes from the original array 
     let timesMinutesArray:[Int] = timesArray.map { stringToMinutes($0) } 

     let dayMinute = stringToMinutes(currentTime) 
     // filter out the times that has already passed 
     let filteredTimesArray = timesMinutesArray.filter{$0 > dayMinute } 

     // get the first time in your array 
     if let firstTime = filteredTimesArray.first { 
      // find its position and extract it from the original array 
      let nextDeparture = timesArray[timesMinutesArray.indexOf(firstTime)!] // "15:40" 


      let userCalendar = NSCalendar.currentCalendar() 


      let dateMakerFormatter = NSDateFormatter() 
      dateMakerFormatter.calendar = userCalendar 
      dateMakerFormatter.dateFormat = "yyyy/MM/dd" 



      // How many hours and minutes between now and the next ferry 

      dateMakerFormatter.dateFormat = "H:mm" 
      let startTime = dateMakerFormatter.dateFromString(currentTime)! 
      let endTime = dateMakerFormatter.dateFromString(nextDeparture)! 
      let hourMinuteComponents: NSCalendarUnit = [.Hour, .Minute] 
      let timeDifference = userCalendar.components(
       hourMinuteComponents, 
       fromDate: startTime, 
       toDate: endTime, 
       options: []) 

      let difference = (timeDifference.hour*60) + (timeDifference.minute) 

      var count = difference 

      print(count) //this returns correctly 


      timer = NSTimer.scheduledTimerWithTimeInterval(1, target: ViewController(), selector: "update", userInfo: nil, repeats: true) 




     } 


    } 

} 


//Picker 

// The number of columns of data 
func numberOfComponentsInPickerView(picker: UIPickerView) -> Int { 
    return 2 
} 

// The number of rows of data 
func pickerView(picker: UIPickerView, numberOfRowsInComponent component: Int) -> Int { 
    return pickerData[component].count 
} 

// The data to return for the row and component (column) that's being passed in 
func pickerView(picker: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? { 
    return pickerData[component][row] 
} 


//Show picker wen text field is click in 
func textFieldShouldBeginEditing(textfield: UITextField) -> Bool { 
    dep.resignFirstResponder() 
    arr.resignFirstResponder() 
    self.dep.tintColor = UIColor.clearColor() 
    self.arr.tintColor = UIColor.clearColor() 

    picker.hidden = false 

    return false 

} 

//Make text uneditable 
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool { 
    return false 
} 


// Catpure the picker view selection 
func pickerView(picker: UIPickerView, didSelectRow row: Int, inComponent component: Int) { 
    // This method is triggered whenever the user makes a change to the picker selection. 
    // The parameter named row and component represents what was selected. 
    print("/[component][row]") 

    let fromto = pickerData[component][row] 


    print(fromto) 

    if component == 0 { 

     var count = calculateTime().count 

     arr.text = "san francisco" 

     dep.text = pickerData[component][row] 

     calculateTime().refreshView(["5:45", "6:35", "7:00", "7:30", "7:50", "8:20", "8:40", "9:15", "10:10", "11:10", "12:40", "14:15", "14:50", "15:40", "16:10", "17:10", "17:40", "18:40", "19:25", "20:50"]) 

     print("help") 

     self.countDownLabel.text = "\(count)" 

     print(count) 

    } 

    else { 

     dep.text = pickerData[component][row] 
    } 



    picker.hidden = true; 
} 


func pickerView(picker: UIPickerView, viewForRow row: Int, forComponent component: Int, reusingView view: UIView?) -> UIView 
{ 
    var pickerLabel = UILabel() 
    pickerLabel.textColor = UIColor(red: CGFloat(41/255.0), green: CGFloat(100/255.0), blue: CGFloat(226/255.0), alpha: CGFloat(1.0)) 
    pickerLabel.text = pickerData[component][row] 
    // pickerLabel.font = UIFont(name: pickerLabel.font.fontName, size: 15) 
    pickerLabel.font = UIFont(name: "Helvetica Neue", size: 20) // In this use your custom font 
    pickerLabel.textAlignment = NSTextAlignment.Center 
    return pickerLabel 
} 
func pickerView(pickerView: UIPickerView, rowHeightForComponent component: Int) -> CGFloat { 
    return 36.0 
} 



func update() { 


    if count == 1{ 
     //self.minutes.text = "minute" 
     print("did change") 
    } 

    if(count > 0) 
    { 
     //countDownLabel.text = String(count--) 

     print(count) 
    } 

    else if (count == 0) 
    { 
     timer.invalidate() 
     print("ended") 
     calculateTime().refreshView(["5:45", "6:35", "7:00", "7:30", "7:50", "8:20", "8:40", "9:15", "10:10", "11:10", "12:40", "14:15", "14:50", "15:40", "16:10", "17:10", "17:40", "18:40", "19:25", "20:50"]) 

    } 



} 

}

Answer 1

你應該在文件的最頂端添加計數變量，以便它是所有功能的文件中訪問。這樣你只有一個計數實例，你可以在整個文件的任何地方更新它。即在文件的頂部：

var count : Int = calculateTime().count 

然後，你可以訪問計數爲你

update() 

函數內完成。

如果它們是在不同的類，那麼你就需要創建一個類的實例，或者，在已經通過這個類的一個實例，例如，如果計數A類初始化：

public class A { 
    var count : Int = 0 
} 

如果你想要再從B類訪問變量，你可以做如下：

public class B { 
    var classA : A = A() 

    print("Count : \(classA.count)") 
} 

這將讓您訪問計數，爲您創建了一個實例。或者，在創建類B的實例時，可以在初始化時傳遞類A的相應實例。例如

public class C { 
    var a : A = A() 
    var b : B = B(class : a) 
} 

public class B { 
    var count : Int 

    init(class : A = A()) { 
     count = class.count 
    } 
} 

此外，裸記住，OOP，你可能會想使用getter和setter方法，而不是僅僅露出計數，使計數私有。即

public class A { 
    private var _count = 0 

    var count : Int { 
     get { 
      return _count 
     } 

     set { 
      if newValue != _count { 
       _count = newValue 
      } 
     } 
    } 
} 

public class B { 
    var classA : A = A() 

    classA.count = 2 // Would set the count of class A, for the particular instance you have created as 2 
} 

這也可以讓你訪問變量。另外，如果這對您沒有幫助，請參閱代表&協議，您也可以通過這種方式傳遞變量。