Swift ScrollView、TextField和pickerview故障

我的问题是，当我运行项目并单击第一个文本字段时，其他文本字段暂时为空，应用程序会崩溃，出现以下错误：

由于未捕获的异常“UIViewControllerHierarchyInconsistency”而终止应用程序，原因：“子视图控制器：应具有父视图控制器：但请求的父视图控制器为：”

这是我的代码：

import UIKit

class ServiceAppointment: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {

    @IBOutlet weak var ScrollView: UIScrollView!

    @IBOutlet weak var pickerView: UIPickerView!

    @IBOutlet weak var StateField: UITextField!

    @IBOutlet weak var CityField: UITextField!

    @IBOutlet weak var VehRegNumberField: UITextField!

    @IBOutlet weak var LocationField: UITextField!

    @IBOutlet weak var CurrentKmsField: UITextField!

    @IBOutlet weak var apptDateFIeld: UITextField!

    @IBOutlet weak var apptTypeField: UITextField!

    @IBOutlet weak var pickupField: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()
        ScrollView.contentSize.height = 1000
        pickerView.hidden = true;
        StateField.text = States[0]
        self.pickerView.dataSource = self;
        self.pickerView.delegate = self;
        self.StateField.inputView = pickerView         
            }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    var States = ["Italy","United States","UK","France"]

    //MARK: - Delegates and data sources
    //MARK: Data Sources
    func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
        return 1
    }
    func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return States.count
    }

    //MARK: Delegates
    func pickerView2(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
        return States[row]
    }

    func pickerView3(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        StateField.text = States[row]
        pickerView.hidden = true;
    }
    func textFieldShouldBeginEditing(textField: UITextField) -> Bool {
        pickerView.hidden = false
        return false
    }
}

我认为这是多视图的问题，因此我在viewDidLoad中写道：

但随后所有的滚动视图都明显消失了

---

我如何才能做到这一点，以便在按下文本字段时，出现pickerview？

我认为您的故事板或XIB有问题。你的UI在哪里？我有视图和scrollview它是一个子视图，然后文本字段在scrollview中我是说你的控制器在哪里？在故事板中还是在XIB中？好的，所以问题在其他地方。检查这个线程：我已经看到了，但是我没有解决这个问题

self.StateField.removeFromSuperView()