Swift 3：如果按下按钮，则将文本添加到标签

Question

在我的 Xcode 项目中，我有五个空文本标签（即 I、II、III、IV、V）和五个按钮，每个按钮代表一个字母（即 a、b、c、d、e）。

我想用字母填充文本标签 I 到 V，但按字母按钮的顺序（即用户按下 c → 标签I包含字母c ；然后用户按下 a → 标签II包含字母a等等）。

你能给我任何提示/解决方案如何做到这一点吗？

谢谢，J。

编辑：在本杰明的建议之后，我现在做了以下工作：

import UIKit

class ViewController: UIViewController {


    // Letter Buttons
@IBOutlet weak var LetterOneButton: UIButton!
@IBOutlet weak var LetterTwoButton: UIButton!
@IBOutlet weak var LetterThreeButton: UIButton!
@IBOutlet weak var LetterFourButton: UIButton!
@IBOutlet weak var LetterFiveButton: UIButton!

// Word Fields
@IBOutlet weak var WordLetterOne: UILabel!
@IBOutlet weak var WordLetterTwo: UILabel!
@IBOutlet weak var WordLetterThree: UILabel!
@IBOutlet weak var WordLetterFour: UILabel!
@IBOutlet weak var WordLetterFive: UILabel!

// Counter
@IBOutlet weak var CounterLabel: UILabel!

// Skip Button
@IBOutlet weak var SkipButtonLabel: UIButton!

// Define Variables
var index: Int = 0
var labels: [UILabel] = [WordLetterOne, WordLetterTwo, WordLetterThree, WordLetterFour, WordLetterFive]
var letters: [String] = ["A", "B", "C", "D", "E"]



override func viewDidLoad() {
    super.viewDidLoad()

    // Set initial letters for LetterButtons
    LetterOneButton.setTitle("A", for: .normal)
    LetterTwoButton.setTitle("U", for: .normal)
    LetterThreeButton.setTitle("T", for: .normal)
    LetterFourButton.setTitle("O", for: .normal)
    LetterFiveButton.setTitle("S", for: .normal)

    // Add button content to WordField
    // Second Attempt

    //you need to set the tags of each button in order for my method to work
    LetterOneButton.tag = 0
    LetterTwoButton.tag = 1
    LetterThreeButton.tag = 2
    LetterFourButton.tag = 3
    LetterFiveButton.tag = 4

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()



}

// Add button content to WordField
// First Attempt

@IBAction func LetterOneButtonPressed(_ sender: AnyObject) {
    labels[index].text = letters[sender.tag]

    index += 1
}

/**
@IBAction func LetterTwoButtonPressed(_ sender: AnyObject) {
    WordLetterTwo.text = LetterTwoButton.currentTitle
}

@IBAction func LetterThreeButtonPressed(_ sender: AnyObject) {
    WordLetterThree.text = LetterThreeButton.currentTitle
}

@IBAction func LetterFourButtonPressed(_ sender: AnyObject) {
    WordLetterFour.text = LetterFourButton.currentTitle
}

@IBAction func LetterFiveButtonPressed(_ sender: AnyObject) {
    WordLetterFive.text = LetterFiveButton.currentTitle
} **/




// Skip Button Action
@IBAction func SkipButtonAction(_ sender: AnyObject) {
}

}

Answer 1

我的建议是将您的标签和字母放在一个数组中：

var labels: [UILabel] = [label1, label2, ...]
var letters: [String] = ["a", "b", ...]

然后你可以创建一个类变量来跟踪有多少按钮被按下：

var index: Int = 0

然后在所有按钮都链接到“touchUpInside”的 IBAction 中，您可以获取所有这些信息并在每次调用时填充一个标签。 这当然需要您将按钮的标签设置为 0、1、2、3、4（分别用于 a 到 e）。

@IBAction func buttonPressed(sender: UIButton){

    switch sender.tag {
    case 0:
        labels[index].text = letters[sender.tag]
    ...
    }

    index += 1

}

编辑：

看到你的代码后，你应该把它改成这样：

 override func viewDidLoad() {
    super.viewDidLoad()

    // Set initial letters for LetterButtons
    LetterOneButton.setTitle("A", for: .normal)
    LetterTwoButton.setTitle("U", for: .normal)
    LetterThreeButton.setTitle("T", for: .normal)
    LetterFourButton.setTitle("O", for: .normal)
    LetterFiveButton.setTitle("S", for: .normal)

    // Add button content to WordField
    // Second Attempt

    //initialize array with real values
    labels = [WordLetterOne, WordLetterTwo, WordLetterThree, WordLetterFour, WordLetterFive]

    //you need to set the tags of each button in order for my method to work
    LetterOneButton.tag = 0
    LetterTwoButton.tag = 1
    LetterThreeButton.tag = 2
    LetterFourButton.tag = 3
    LetterFiveButton.tag = 4

}

对于索引变量和数组，请确保在任何函数之外对其进行初始化。 将它们初始化为标签和按钮旁边的类变量，如下所示：

@IBOutlet weak var WordLetterOne: UILabel!
@IBOutlet weak var WordLetterTwo: UILabel!
@IBOutlet weak var WordLetterThree: UILabel!
@IBOutlet weak var WordLetterFour: UILabel!
@IBOutlet weak var WordLetterFive: UILabel!

var index: Int = 0

var labels: [UILabel] = [UILabel]() //empty intialization

var letters: [String] = ["A", "B", "C", "D", "E"]

然后，您需要将其他方法更改为如下所示：

@IBAction func LetterOneButtonPressed(sender: UIButton) {
    //you can actually omit the switch statement in your case
    labels[index].text = letters[sender.tag]

    index += 1
}

请记住，您需要将每个按钮链接到上述方法。 每个按钮不要有不同的方法！

Answer 2

希望这会帮助你。

override func viewDidLoad() {
    super.viewDidLoad()

    var x = 0, y = 0, buttonWidth = 50, buttonHeight = 50

    for i in 0...5 {
        let tempButton = UIButton()
        tempButton.frame = CGRect(x: (x+5), y: (y+5), width: (buttonWidth-10), height: (buttonHeight-10))
        tempButton.tag = i
        tempButton.addTarget(self, action: #selector(buttonTapped(withButton: tempButton)), for: UIControlEvents.touchUpInside)
        tempButton.backgroundColor = .red

        x += buttonWidth
        self.view.addSubview(tempButton)
    }
}
func buttonTapped(withButton button:UIButton){
        let label:UILabel = UILabel() //your label
        if(button.tag == 0){
            label.text = "I"
        }else if(button.tag == 1){
            label.text = "II"
        }else if(button.tag == 2){
            label.text = "III"
        }else if(button.tag == 3){
            label.text = "IV"
        }else if(button.tag == 4){
            label.text = "V"
        }

    }