斯威夫特計算器。「0」仍然在屏幕上

-1

在代碼中是一個小問題，我試圖解決但尚未找到解決方案。
此代碼適用於計算器。
它正在做正確的計算。
但是當我按下「清除」按鈕時，在新計算之前仍然是「0」。
例如：我按「清除」和「2」後。屏幕上會出現「02」。
如果有人會查看代碼並查看解決方案，我將不勝感激。斯威夫特計算器。「0」仍然在屏幕上

import UIKit 
import AVFoundation 

class ViewController: UIViewController { 


@IBOutlet weak var outputLbl: UILabel! 
var btnSound: AVAudioPlayer! 

@IBAction func clearBtnPressed(_ sender: Any) { 
    playSound() 
    runningNumber = "" 
    leftValStr = "" 
    outputLbl.text = "" 
    currentOperation = Operation.Empty 
} 

enum Operation: String { 
    case Divide = "/" 
    case Multiply = "*" 
    case Subtract = "-" 
    case Add = "+" 
    case Empty = "Empty" 
} 

var currentOperation = Operation.Empty 
var runningNumber = "" 
var leftValStr = "" 
var rightValStr = "" 
var result = "" 


override func viewDidLoad() { 
    super.viewDidLoad() 

    let path = Bundle.main.path(forResource: "btn", ofType: "wav") 
    let soundURL = URL(fileURLWithPath: path!) 

    do { 
     try btnSound = AVAudioPlayer(contentsOf: soundURL) 
     btnSound.prepareToPlay() 
    } catch let err as NSError { 
     print(err.debugDescription) 
    } 
    outputLbl.text = "" 
} 


@IBAction func numberPressed(sender: UIButton) { 
    playSound() 
    runningNumber += "\(sender.tag)" 
    outputLbl.text = runningNumber 

} 

@IBAction func onDividePressed(sender: AnyObject) { 
    processOperation(operation: .Divide) 
} 

@IBAction func onMultiplyPressed(sender: AnyObject) { 
    processOperation(operation: .Multiply) 
} 

@IBAction func onSubtractPressed(sender: AnyObject) { 
    processOperation(operation: .Subtract) 
} 

@IBAction func onAddPressed(sender: AnyObject) { 
    processOperation(operation: .Add) 
} 

@IBAction func onEqualPressed(sender: AnyObject) { 
    processOperation(operation: currentOperation) 
} 


func playSound() { 
    if btnSound.isPlaying { 
     btnSound.stop() 
    } 
    btnSound.play() 
} 

func processOperation(operation: Operation) { 
    playSound() 
    if currentOperation != Operation.Empty { 
     if runningNumber != "" { 
      rightValStr = runningNumber 
      runningNumber = "" 

      if currentOperation == Operation.Multiply { 
       result = "\(Double(leftValStr)! * Double(rightValStr)!)" 
      } else if currentOperation == Operation.Divide { 
       result = "\(Double(leftValStr)!/Double(rightValStr)!)" 
      } else if currentOperation == Operation.Subtract { 
       result = "\(Double(leftValStr)! - Double(rightValStr)!)" 
      } else if currentOperation == Operation.Add { 
       result = "\(Double(leftValStr)! + Double(rightValStr)!)" 
      } 

      leftValStr = result 
      outputLbl.text = result 
     } 

     currentOperation = operation 
    } else { 
     leftValStr = runningNumber 
     runningNumber = "" 
     currentOperation = operation 
    } 
} 
}

來源

2017-02-03 Tim

給你的numberPressed添加一個條件來檢查'if if =='0''替換它否則將它追加到字符串 –

按'clear'後'0'來自哪裏？添加數字時，您處理的是文本而不是數字，因此前導零仍然存在。 – vadian

0從Operation.Empty
來到我解決了以下方法這個問題：
if (runningNumber == "0") { runningNumber.remove(at: runningNumber.startIndex) }
我不知道，這個解決方案是最佳的，但現在的計算器可以完美運行
我感謝大家誰花時間來幫助。感謝你們！

來源

2017-02-06 15:01:31 Tim

檢查您IBOutlets（也許你有明確的按鈕，這也是綁定到numberPressed方法）
檢查您的按鈕標籤
添加日誌裏面numberPressed（）來檢查，如果出現錯誤與 runningNumber

來源

2017-02-03 17:53:42

斯威夫特計算器。 「0」仍然在屏幕上

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斯威夫特計算器。「0」仍然在屏幕上