Question

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

为清楚起见，这是我的简单协议：

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

我为选择器提供了多种颜色：

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

然后是一个空字符串变量，用于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，将调用委托方法，并且我需要提供UIColor。目前，它显然不起作用，因为我在需要String时尝试传递UIColor：

@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String的选择器从选择器转换为UIColor，或者可能采取另一种方法来使不必要的选择和另一种方式实现。

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[String : UIColor]字典：

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

然后只用字符串查找颜色：

let color = dict[favoriteColor]!

或者您可以将colors和String的{{1}}数组配对：

UIColor

然后在需要字符串时：

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

以及当您需要颜色时：

colors[row].string

将字符串选择从UIPicker转换为UIColor的最简单方法？

1 个答案: