Question

public class CustomSelectFields: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
    let cities = ["city1", "city2"]
    let selectiveTextField = UITextField()
    let pickerView = UIPickerView()


    //normally it will get array of cities and frame position

    public func CreateCustomSelectField() -> UITextField {

        selectiveTextField.frame = CGRect(x: ScreenSize.width * 0.1, y: ScreenSize.height * 0.4, width: ScreenSize.width * 0.8, height: ScreenSize.height * 0.1)
        selectiveTextField.placeholder = "Placehoder"
        selectiveTextField.inputView = pickerView

        //should i declare delegates and datasoruce here?
        pickerView.delegate = self
        pickerView.dataSource = self

        return selectiveTextField
    }

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

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

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

    public func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        selectiveTextField.text = cities[row]
        selectiveTextField.resignFirstResponder()
    }

}

我正在尝试创建自定义UIPickerView，我希望它在其他类中使用。当我在同一个类中声明它的委托和数据源时，数据没有显示出来。

此外，我尝试在类中声明我用于viewController，如下所示：

let textField = customElements.CreateCustomSelectField()
customElements.pickerView.delegate = ??
customElements.pickerView.dataSource = ??

self.view.addSubview(textField)

我如何完成此委托＆amp;数据源问题？

Answer 1

您的设计和代码都是乱码。您已经定义了一个类CustomSelectFields，看起来您希望它管理文本字段和选择器视图。然后你有一个方法CreateCustomSelectField，听起来像是CustomSelectFields类的便利初始值设定项。但是，它实际上是一个实例方法，用于配置和返回属于UITextField类的CustomSelectFields。

您的CustomSelectFields类符合UIPickerViewDelegate和UIPickerViewDataSource协议，这表明您打算将其作为选择器视图的委托。如果是这种情况，CustomSelectFields类应该有一个初始化程序，用于创建选择器视图和文本字段并最初配置它们。

这样的事情：

public class CustomSelectFields: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {

  let cities = ["city1", "city2"]
  let selectiveTextField: UITextField
  let pickerView: UIPickerView

  init() {
    selectiveTextField = UITextField()
    selectiveTextField.frame = CGRect(x: ScreenSize.width * 0.1, 
      y: ScreenSize.height * 0.4, 
      width: ScreenSize.width * 0.8, 
      height: ScreenSize.height * 0.1)
    selectiveTextField.placeholder = "Placehoder" //Hodor! HODOR!
    selectiveTextField.inputView = pickerView

    pickerView.delegate = self
    pickerView.dataSource = self

    pickerView = UIPickerView()
    pickerView.delegate = self
    pickerView.dataSource = self
  }
}

但即便如此，拥有一个创建和配置视图对象的类 - 但不显示或管理它们 - 有点奇怪。

在Swift的另一个类中声明self

1 个答案: