Question

我有一个UIButton，当我按下它时我想切换标题和颜色。按钮应该有三种状态：每日，每月和每年。

现在我有这个看起来不那么优雅的解决方案：

if sender.currentTitle == "Daily" {
    sender.setTitle("Monthly", for: .normal)
    sender.setTitleColor(UIColor(hex: "FB967F"), for: .normal)
} else if sender.currentTitle == "Monthly" {
    sender.setTitle("Yearly", for: .normal)
    sender.setTitleColor(UIColor(hex: "A395CE"), for: .normal)
} else if sender.currentTitle == "Yearly" {
    sender.setTitle("Daily", for: .normal)
    sender.setTitleColor(UIColor(hex: "75CFF8"), for: .normal)
}

在Swift中有更方便的方法吗？

Answer 1

使用枚举这是维持国家的最佳选择。保持您的代码超级干净和可读。

enum ButtonState {
    case daily
    case monthly
    case yearly

    mutating func next(forButton button:UIButton) {
        switch (self) {
        case .daily:
            self = .monthly
        case .monthly:
            self = .yearly
        case .yearly:
            self = .daily
        }

        button.setTitle(self.getTitle(), forState: .Normal)
        button.setTitleColor(UIColor(hex: self.getTitleColorHex()), forState: .Normal)
    }

    private func getTitle() -> String {
        switch (self) {
        case .daily:
            return "Daily"
        case .monthly:
            return "Monthly"
        case .yearly:
            return "Yearly"
        }
    }

    private func getTitleColorHex() -> String {
        switch (self) {
        case .daily:
            return "FB967F"
        case .monthly:
            return "A395CE"
        case .yearly:
            return "75CFF8"
        }
    }
}

var currentButtonState = ButtonState.daily

func changeButtonState(forButton button:UIButton) {
    currentButtonState.next(forButton: button)
}

Answer 2

声明counter变量和两个数组

var counter = 0
let titleArray = ["Daily", "Monthly", "Yearly"]
let colorArray = ["FB967F", "A395CE", "75CFF8"]

然后递增计数器（通过模运算符将其保持在0 ... 2范围内）并从数组中获取标题和颜色值

counter = (counter + 1) % titleArray.count
sender.setTitle(titleArray[counter], for: .normal)
sender.setTitleColor(UIColor(hex: colorArray[counter]), for: .normal)

Answer 3

我真的不认为你的代码是所以不优雅 - 三态不是那么复杂以至于难以阅读（这实际上是代码不雅的问题），但是，如果它超过三个你肯定想要更整洁的东西。如何使用状态转换字典：

func newButtonState(sender: UIButton) {
    let buttonDict = ["Yearly": (UIColor.red, "Daily"), 
                      "Monthly": (UIColor.green, "Yearly"), 
                      "Daily": (UIColor.yellow, "Monthly")]
    if let t = sender.currentTitle, let n: (UIColor, String) = buttonDict[t] {
        sender.setTitle(n.1, for: .normal)
        sender.setTitleColor(n.0, for: .normal)
    }
}

使用UIButton在三个状态之间切换

3 个答案: