Swift代碼錯誤：類型字符串的值有沒有成員Int

我是新來這個網站，請裸露在我身邊。我想在Swift中構建一個簡單的計算器，但我不知道如何或爲什麼我得到錯誤（「字符串類型的值沒有成員類型Int」）或如何解決它。這是到目前爲止我的代碼：Swift代碼錯誤：類型字符串的值有沒有成員Int

class ViewController: UIViewController { 
    var isTypingNumber = false 
    var firstNumber = Int!() 
    var secondNumber = Int!() 
    var operation = "" 

@IBOutlet weak var calculatorDisplay: UILabel! 


@IBAction func acButtonTapped(sender: AnyObject) { 

} 
@IBAction func number7Tapped(sender: AnyObject) { 
    let number7 = sender.currentTitle 
    if isTypingNumber{ 
     calculatorDisplay.text = calculatorDisplay.text! + number7!! 
    }else{ 
     calculatorDisplay.text = number7 
     isTypingNumber = true 
    } 
} 
@IBAction func divideTapped(sender: AnyObject) { 
    isTypingNumber = false 

    firstNumber = calculatorDisplay.text?.Int()! **//Error: Value of type 'String' has no member 'Int'** 
    operation = sender.currentTitle!! 
} 

@IBAction func equalsTapped(sender: AnyObject) { 
    isTypingNumber = false 
    var result = 0 
    secondNumber = calculatorDisplay.text?.Int()! **//Error: Value of type 'String' has no member 'Int'** 

    if operation == "+" { 
     result = firstNumber + secondNumber 
    } else if operation == "-" { 
     result = firstNumber - secondNumber 
    }else if operation == "X" { 
     result = firstNumber * secondNumber 
    }else if operation == "÷"{ 
     result = firstNumber/secondNumber 
} 
    calculatorDisplay.text = "\(result)" 
} 



override func viewDidLoad() { 
    super.viewDidLoad() 
    // Do any additional setup after loading the view, typically from a nib. 

    firstNumber = 0 
    secondNumber = 0 
} 

override func didReceiveMemoryWarning() { 
    super.didReceiveMemoryWarning() 
    // Dispose of any resources that can be recreated. 
}

}

哪兒我去錯了嗎？

來源

2016-06-07 Geniouse

不要濫用武力展開操作符（''！）這樣的。 – Alexander

相反的：

firstNumber = calculatorDisplay.text?.Int()!

你想要的東西，如：

if let text = calculatorDisplay.text? { 
    firstNumber = Int(text)! 
}

或者，如果你想住在邊緣：

firstNumber = Int(calculatorDisplay.text!)!

來源

2016-06-07 17:31:18

由於您正在學習Swift，因此我會鼓勵您在不使用'！'的情況下編寫所有代碼（瞭解'如果let'，'guard let'和可選的鏈接代替）。 –

或'calculatorDisplay.text.flatMap {Int（$ 0）}''如果你想得到時髦的 – Hamish

@ originaluser2 ...不要給他們點子......：p – Alexander

有一個在沒有Int()方法String類型。

要轉換Int到String，試試這個：

guard let text = calculatorDisplay.text else { 
    //the CalculatorDisplay has no text, deal with it accordingly 
} 
guard let firstNumber = Int(text) else { 
    //the CalculatorDisplay has text, but it's not a valid Int 
} 

//use firstNumber

來源

2016-06-07 17:31:42 Alexander

Swift代碼錯誤：類型字符串的值有沒有成員Int

回答

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