ios - 确定哪个 UIPicker 的工具栏按钮发送了消息

Question

我想在一个页面上使用多个 UIPickers。我想我已经配置了几乎所有的东西。当我使用 UIPicker 时，我添加了一个带有“取消”和“完成”按钮的工具栏。

工具栏是使用相同的函数构建的，因此当用户点击“完成”时它会调用相同的操作。下面是一个伪示例流程。

 let pickerData: [String] = ["1", "2", "3", "4"]
 var picker = UIPickerView()
 let pickerData2: [String] = ["A", "B", "C", "D"]
 var picker2 = UIPickerView()

 @IBOutlet weak var textField: UITextField!
 @IBOutlet weak var textField2: UITextField!

override func viewDidLoad() {
  super.viewDidLoad()
  // set up pickers
  setPickerView()
}    

// set the pickerview
func setPickerView(){
    picker.dataSource = self
    picker.delegate = self
    textField.inputView = picker
    textField.inputAccessoryView = initToolBar()
    // second picker
    picker2.dataSource = self
    picker2.delegate = self
    textField2.inputView = picker
    textField2.inputAccessoryView = initToolBar()
}

// build the toolbar for uipicker, so a user can select a value
func initToolBar() -> UIToolbar {
    let toolBar = UIToolbar()
    toolBar.barStyle = UIBarStyle.default
    toolBar.isTranslucent = true
    toolBar.tintColor = UIColor(red:14.0/255, green:122.0/255, blue:254.0/255, alpha: 1)
    toolBar.sizeToFit()
    // TODO need to update actions for all buttons
    let cancelButton = UIBarButtonItem(title: "Cancel", style: UIBarButtonItemStyle.plain, target: self, action: nil)
    let doneButton = UIBarButtonItem(title: "Done", style: UIBarButtonItemStyle.plain, target: self, action: #selector(pickerDoneAction))
    let spaceButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.flexibleSpace, target: nil, action: nil)
    toolBar.setItems([cancelButton, spaceButton, doneButton], animated: false)
    toolBar.isUserInteractionEnabled = true

    return toolBar
}

func pickerDoneAction(sender: UIBarButtonItem){
     /*Here I'm just updating the same textfield when the done button is
       is pressed, I'm not sure how I can get the instance of the picker into this method*/
     let indexPath = picker.selectedRow(inComponent: 0)
     textfield.text = data[indexPath]
}

// delegates
func numberOfComponents(in pickerView: UIPickerView) -> Int { return 1 }
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
  if pickerView == picker {
    return pickerData.count
    } else return pickerData2.count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
  if pickerView == picker {
    return pickerData[row]
  } else return pickerData2[row]
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
  if pickerView == picker {
    textField.text = pickerData[row]
  } else textField2.text = pickerData2[row]
}

有没有办法确定单击完成按钮时使用的是哪个 UIPicker，这样我就可以在我的 pickerDoneAction 方法中使用该实例，然后更改相应文本字段的值？我尝试检查文本字段是否为 firstResponder，甚至尝试检查 UIPicker 本身，但这似乎不可能。我是否需要改变我的方法？如果需要，如何改变？

更新我在现有的 UIPicikerView 委托(delegate)方法中添加了。

澄清一下，我希望在用户按下“完成”时将 UIPicker 的值分配给正确的文本字段，因此如果用户想从 UIPicker 中选择第一行, 它被插入。

Answer 1

您可以实现以下 UIPickerViewDelegate 的方法:

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

当用户在组件中选择一行并使用时，选择器 View 调用该方法

pickerView

(表示请求数据的选择器 View 的对象)知道使用了哪个选择器 View 。