swift - 如何将 UIPickerview selectRow 重置为默认零行

Question

我有一个带有 UIPickerview 的应用程序，有 2 个组件，从 2 个数组获取数据。当选择组件 0 中的第 1 行时，我已在第 3 行设置了第二个组件。这很好，但我的问题是当组件 0 中的 row 发生更改时，我希望组件 1 重置为第 0 行(默认)。

@IBOutlet weak var myPicker: UIPickerView!

let firstArray = ["a", "b", "c", "d"]
let secondArray = ["A", "B", "C", "D"]

override func viewDidLoad() {
    super.viewDidLoad()
    myPicker.delegate = self
    myPicker.dataSource = self
}

func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 2
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    switch component {
    case 0: return firstArray.count
    case 1: return secondArray.count
    default: break
    }
    return 0
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    switch component {
    case 0: return firstArray[row]
    case 1: return secondArray[row]
    default: break
    }
    return ""
}

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {

    if myPicker.selectedRow(inComponent: 0) == 1 {
        myPicker.selectRow(3, inComponent: 1, animated: true)
    }
}

Answer 1

只需使用else if来选择组件中的第一个行，1为，

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {

    if myPicker.selectedRow(inComponent: 0) == 1 {
        myPicker.selectRow(3, inComponent: 1, animated: true)
    } else if component == 0 {
        myPicker.selectRow(0, inComponent: 1, animated: true)
    }
}