swift - 将字符串选择从 UIPicker 转换为 UIColor 的最简单方法？

Question

我正在练习委托(delegate)，在我的练习项目中，我试图让用户从选择器中选择他们最喜欢的颜色，然后在委托(delegate)方法中使用该颜色(作为 UIColor)。

为清楚起见，这是我的简单协议(protocol):

protocol PersonDelegate {
    func makePerson(name: String, color: UIColor)
}

我为选择器准备了一组颜色:

let colors = ["Red", "Orange", "Yellow", "Green", "Blue", "Cyan", "White", "Black"]

然后一个空字符串变量将用户的选择传递给:

var favoriteColor = ""

我的选择器方法是:

func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 1
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    return colors[row]
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return colors.count
}

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    favoriteColor = colors[row]
}

现在，当按下完成按钮时，将调用委托(delegate)方法，我需要提供一个 UIColor。现在显然它不起作用，因为我试图在需要 UIColor 时传入 String:

@IBAction func doneButtonPressed(_ sender: Any) {

    let name = nameTextField.text
    let myColor = favoriteColor

    personDelegate.makePerson(name: name!, color: myColor)

    dismiss(animated: true, completion: nil)
}

我想知道如何将选择器中的 String 选择转换为 UIColor，或者可能采用不同的方法来避免这种情况并以另一种方式进行.

编辑:到目前为止的完整代码

protocol PersonDelegate {
    func makePerson(name: String, color: UIColor)
}

class DelegateController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {

@IBOutlet weak var nameTextField: UITextField!
@IBOutlet weak var colorPicker: UIPickerView!
var personDelegate: PersonDelegate!
let colors: [(string: String, color: UIColor)] = [("Red", .red), ("Orange", .orange), ("Yellow", .yellow), ("Green", .green), ("Blue", .blue), ("Cyan", .cyan)]
var favoriteColor: UIColor

override func viewDidLoad() {
    super.viewDidLoad()

}

func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 1
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    return colors[row].string
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return colors.count
}

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    favoriteColor = colors[row].color
}

@IBAction func doneButtonPressed(_ sender: Any) {

    let name = nameTextField.text
    let myColor = favoriteColor

    personDelegate.makePerson(name: name!, color: myColor)

    dismiss(animated: true, completion: nil)
}

Answer 1

创建一个 [String : UIColor] 字典:

let dict = ["Red": UIColor.red, "Green": UIColor.green, ...]

然后用字符串查找颜色:

let color = dict[favoriteColor]!

---

或者您可以让您的colors 数组与String 和UIColor 配对:

let colors: [(string: String, color: UIColor)] = [("Red", .red), ("Green", .green)]

然后当你需要字符串的时候:

colors[row].string

当你需要颜色时:

colors[row].color