使用两个 UIPickerViews 时出现问题 - 第一个有效，第二个无效

Question

我试图在两个不同的文本框上使用两个选取器视图(我将它们对齐在文本框下方并隐藏它们直到被调用(。 我隐藏选取器视图，直到我准备好使用并将两个文本框绑定到相应的文本框。 第一个选择器视图工作正常，但是当我单击第二个时，我的列表没有出现，它似乎仍然隐藏。 我已经多次阅读代码，但找不到问题，并且观看了多个视频并检查了苹果文档无济于事。 下面发布的代码以供查看和帮助。 提前感谢！

class fifthViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource, UITextFieldDelegate {
    @IBOutlet weak var heightInput: UITextField!
    @IBOutlet weak var weightInput: UITextField!
    @IBOutlet weak var bmiOutput: UITextField!
    @IBOutlet weak var weightPicker: UIPickerView!
    @IBOutlet weak var heightPicker: UIPickerView!
    var height = ["48", "49", "50"]
    var weight = ["90", "91", "92"]
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1
    }
    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        var countrows : Int = height.count
        if pickerView == weightPicker {
        countrows = self.weight.count
        }
        return countrows
    }
    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        if pickerView == heightPicker {
        let titleRow = height[row]
            return titleRow
        }
        else if pickerView == weightPicker {
            let titleRow = weight[row]
            return titleRow
        }
        return ""
    }
    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        if pickerView == heightPicker {
            self.heightInput.text = self.height[row]
            self.heightPicker.isHidden = true
        }
        else if pickerView == weightPicker {
            self.weightInput.text = self.weight[row]
            self.weightPicker.isHidden = true
        }
    }
    func textFieldDidBeginEditing(_ textField: UITextField) {
        if (textField == self.heightInput) {
            self.heightPicker.isHidden = false
        }
        else if (textField == self.weightInput) {
            self.weightInput.isHidden = false
        }
    }```

Answer 1

在 textFieldDidBeginEditing() 中，您需要将self.weightPicker.isHidden设置为 false 而不是 self.weightInput.isHidden 。

func textFieldDidBeginEditing(_ textField: UITextField) {
    if (textField == self.heightInput) {
        self.heightPicker.isHidden = false
    }
    else if (textField == self.weightInput) {
        self.weightPicker.isHidden = false
    }
}

---

修改代码以使用 inputView

我同意@PaulW11的评论：

"如果你制作了选择器视图，你几乎肯定会更好 每个文本字段的输入视图。

以下是基本设置所需的更改。 摆脱情节提要中的选取器并断开@IBOutlet连接。

然后添加这些修改：

// These are no longer outlets since they're created in code
var weightPicker: UIPickerView!
var heightPicker: UIPickerView!
override func viewDidLoad() {
    super.viewDidLoad()
    // set up the picker views
    self.weightPicker = UIPickerView()
    self.weightPicker.delegate = self
    self.weightPicker.dataSource = self
    self.heightPicker = UIPickerView()
    self.heightPicker.delegate = self
    self.heightPicker.dataSource = self
    self.heightInput.inputView = self.heightPicker
    self.weightInput.inputView = self.weightPicker
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    if pickerView == heightPicker {
        self.heightInput.text = self.height[row]
        // make picker go away after value has been selected
        self.heightInput.resignFirstResponder()
    }
    else if pickerView == weightPicker {
        self.weightInput.text = self.weight[row]
        // make picker go away after value has been selected
        self.weightInput.resignFirstResponder()
    }
}