Question

我正在尝试在页面上使用多个UIPickers。我想我几乎配置了一切。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。

工具栏使用相同的功能构建，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]
}

有没有办法确定在单击完成按钮时使用了哪个UIPicker，所以我可以在pickerDoneAction方法中使用该实例，然后更改相应的文本字段的值？我试着检查textfield是否是firstResponder，甚至试图检查UIPicker本身，但似乎不可能。我是否需要改变我的方法，如果是这样的话？

更新我添加了现有的UIPicikerView委托方法。

为了澄清，我想在用户按下“完成”时将UIPicker的值分配给正确的文本字段，因此如果用户想要从UIPicker中选择第一行，它会得到插入。

Answer 1

您可以实现以下UIPickerViewDelegate的方法：

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

当用户选择组件中的行并使用

时，选择器视图调用该方法

pickerView

（表示请求数据的选择器视图的对象）知道哪个选择器视图已被使用。

Answer 2

您始终可以使用try { var threads = fs.readFileSync('./database/threadList.txt'); var threadIds = threads.toString().split('\n'); for(i in threadIds) { threadArray[i] = threadIds[i].split(","); } console.log("This works: " + threadArray[0]); } catch (e) { console.error("Error reading file: ", e); }的{{1}}属性传递数据：

UIView

Answer 3

您可以尝试使用您设置为pickerview的数据源的不同条件动态更改数据

Answer 4

也许您不需要确定它是哪个选择器，而是确定哪个文本字段。

在pickerDoneAction(sender:)中，使用let textField = sender.superview.superview，其中sender为按钮，parent为工具栏，工具栏的parent为文本字段。然后用pickerData[0]填充它。

实现相同目标的另一种方法是使用UITextFieldDelegate的方法textFieldDidEndEditing(_:)。当文本字段结束编辑时，在那里插入默认值。

Answer 5

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

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

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

Answer 6

您可以简单地检查哪个文本字段处于编辑状态。在完成的单击功能中执行此操作。您不必在pickerView或textField中添加任何标签。

 func pickerDoneAction(sender: UIBarButtonItem) {
    if textField1.isEditing == true {
        Print("pickerview 1 is selected")
    } else {
        Print("pickerview 2 is selected")
    }
}

希望这会有所帮助！：）

确定哪个UIPicker的工具栏按钮发送了一条消息

6 个答案: