快捷一键3条信息

Question

我是Swift的新手，正在Xcode上进行编码。 我正在尝试做一个“你好，世界！” 在Swift中使用一个只有一个屏幕，一个按钮和一个显示标签的应用。

我的目标是通过单击按钮来显示三种不同的消息。 为了明确起见，每次单击按钮时，都会循环显示消息。

我尝试用switch解决它，这是我的（未完成的尝试）

import UIKit

class ViewController: UIViewController {
    @IBOutlet weak var textBox: UILabel!

    var userTapped = false

    @IBAction func tappedMe(_ sender: UIButton) {
        let me =
        if userTapped {
            switch me {
            case me : textBox.text = "Hello, World!"
            case me : textBox.text = "Hello, Human!"
            case me : textBox.text = "OK scram."
            default : break
            }
        userTapped = true
        }
    }
}

我不确定我能使me等于什么，或者我的解决方案是否很好。

Answer 1

如果我正确理解，您可以执行以下操作以实现您的目标：

import UIKit

class ViewController: UIViewController {
@IBOutlet weak var textBox: UILabel!

// Integer to track number of times button has been tapped
var tapCount = 0

// Max total of text variations, for this case 2 (you have three different values, but always start with zero)
let max = 2 

@IBAction func tappedMe(_ sender: UIButton) {
    // Try different conditions for value of tapCount
    switch tapCount {
        case 0: 
            textBox.text = "Hello, World!"
        case 1: 
            textBox.text = "Hello, Human!"
        case 2: 
            textBox.text = "OK scram."
        default : break
    }

    // If this is the max number of times you want to display changing text, reset tapCount to zero, otherwise increment tapCount.
    if tapCount < max {
        tapCount += 1
    } else {
        tapCount = 0
    }
} 


}

Answer 2

class ViewController: UIViewController {

    @IBOutlet weak var textBox: UILabel!

    let strings = ["Hello, World!", "Hello, Human!", "OK scram."]
    var tapCount = 0

    @IBAction func tappedMe(_ sender: UIButton) {
        textBox.text = strings[tapCount]
        tapCount = (tapCount + 1) % strings.count
    }

}