子类 UIPickerView swift

Question

我正在尝试创建 UIPickerView 的子类，以便我可以在多个视图中使用我的选择器。我正在尝试以编程方式将我的选取器调用为 UITextField 的 inputView，但我不知道如何正确初始化它。我怀疑这是否是正确的方法以及如何让它发挥作用。希望大家能帮帮我。

UIPickerView 子类：

import UIKit

 class GroupPicker : UIPickerView, UIPickerViewDelegate, UIPickerViewDataSource{

    var cdm = CoreDataManager()
    var groupObjList : [Group]!

    init() {
       groupObjList = cdm.groupList()
    }

    //MARK: - Delegates and data sources

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

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

    func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
        return groupObjList[row].title
    }

    func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        println("picked \(groupObjList[row].title)")

    }        
}

我如何尝试在视图控制器中调用它：

override func viewDidLoad() {
    super.viewDidLoad()

    groupPicker = GroupViewPicker()  //instead of UIPickerView()
    groupField.inputView = groupPicker
}

Answer 1

我想你会想展示这个 modally?

如果是这样，您可以执行以下操作：

override func viewDidLoad() {
    super.viewDidLoad()

    groupPicker = GroupViewPicker()  //instead of UIPickerView()
    //Send the data you want your picker view to handle.
    groupPicker.groupObjList = dataForPickerView
    self.presentViewController(viewControllerToPresent: groupPicker, animated: , completion: nil)
}

它应该弹出并以模态方式呈现自己

提示：

如果您从不将组传递给此数组（即您没有如上所示设置属性），则此 var groupObjPicker: [Group]! 将会崩溃。更安全的方法（取决于您要实现的目标）是将其声明为像 var groupObjList = [Group]() 这样的空数组。然后你知道如果没有传递给它，它至少会 return 0 当 .count 被调用时等等

Answer 2

像这样很容易。

GroupPicker : UIPickerView {

        override init(frame: CGRect){
            super.init(frame: frame)
            self.groupObjList = cdm.groupList()
        } 
}

称呼它：

viewDidLoad() {
    groupField.inputView = GroupPicker(frame: CGRectZero)
}

Answer 3

您必须重写您的 init 方法

required init(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

override init(frame: CGRect) {
    super.init(frame:frame)
    self.delegate = self
    self.dataSource = self
}

子类 UIPickerView swift

Subclass UIPickerView swift

ios

swift

uipickerview