Question

我正在尝试将一个字符串从一个if语句传递给另一个。我已经在两个if语句之外声明了var，现在只有占位符字符串。

应该发生的是，按一下按钮，它会显示按钮的标题（想想计算器上的按钮/数字）。当第二次点击按钮时，它应显示第一个按钮的标题和按下的第二个按钮的标题，以便创建一个两位数的数字。

实际发生的是它正确显示第一个按钮，但是一旦第二个按钮被按下，它会显示第一个按钮作为占位符字符串。

代码如下。任何帮助都会很棒！

app + code的屏幕截图..新卡旁边应该是“21”而不是“place 1”http://imgur.com/vMmciyh

@IBAction func oneButtonPressed(sender: AnyObject)
{

    timesButtonPressed += 1
    var buttonTitle1:String! = ("Place ")
    var buttonTitle2:String! = ("holder")


    if timesButtonPressed == 1
    {

        buttonTitle1 = sender.titleLabel!?.text

        self.answerTyped.text = String (buttonTitle1)

    }



    if timesButtonPressed == 2
    {
       buttonTitle2 = sender.titleLabel!?.text

       self.answerTyped.text = String (stringInterpolation: buttonTitle1, buttonTitle2)
    }


}

完整代码：

导入UIKit

类PlayViewController：UIViewController {

@IBOutlet weak var newCardButton: UIButton!
@IBOutlet weak var labelTest: UILabel!
@IBOutlet weak var oneButton: UIButton!
@IBOutlet weak var answerTyped: UILabel!
@IBOutlet weak var enterButton: UIButton!



var mathProblem = String ("Answer Typed")
var firstRandomNumber = 0
var secondRandomNumber = 0
var buttonName = String ("button name")
var timesButtonPressed = 0


override func viewDidLoad() {
    super.viewDidLoad()


    // Do any additional setup after loading the view.
}

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

@IBAction func newCardButtonPressed(sender: AnyObject)
{

    firstRandomNumber = Int(arc4random_uniform(11))
    secondRandomNumber = Int(arc4random_uniform(11))

    mathProblem = String(format:"%i x %i", firstRandomNumber, secondRandomNumber)


    self.labelTest.text = String (mathProblem)

}


@IBAction func oneButtonPressed(sender: AnyObject)
{

    timesButtonPressed += 1
    var buttonTitle1:String! = ("Place ")
    var buttonTitle2:String! = ("holder")


    if timesButtonPressed == 1
    {
        buttonTitle1 = sender.titleLabel!?.text

        self.answerTyped.text = buttonTitle1

    }


    if timesButtonPressed == 2
    {
       buttonTitle2 = sender.titleLabel!?.text

        self.answerTyped.text = buttonTitle1 + buttonTitle2


    }



}

Answer 1

问题是当你第二次按下按钮然后是timesButtonPressed == 1，从未执行过，而你的timesButtonPressed == 2如果block从代码中获取title1的值而不是实际的button1标题值。

var timesButtonPressed : NSInteger = 0
var displayString : String = "0"

@IBAction func oneButtonPressed(sender: AnyObject)
{
    timesButtonPressed += 1
    let buttonTitle:String! = sender.titleLabel!?.text

    if timesButtonPressed == 1
    {
        displayString = buttonTitle
    } else {
        displayString += buttonTitle
    }
    self.answerTyped.text = displayString
}

timesButtonPressed var需要根据需要使用（或者在timesButtonPressed = 0时清除显示字符串）

Answer 2

编辑：

您需要在IBAction函数之外定义两个变量。将以下两个变量放在viewDidLoad（）

中

var buttonTitle1:String! = ("Place ")
var buttonTitle2:String! = ("holder")

您可以通过重载“+”来替换添加两个字符串：

var str1: String = "Hello"
var str2: String = "World"
var str3: String = str1 + str2

同样，您可以在函数中执行此操作：

self.answerTyped.text = buttonTitle1 + buttonTitle2

在varift中将var从一个if语句传递给另一个

2 个答案: