迅速將UIPickerView設置為UITextField的輸入

Question

我是快速編程的新手，我想將UIPickerView設置為UITextField的輸入。 這是我的代碼：

import UIKit

class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {

    @IBOutlet var  selectTransportCompany: UITextField!
    var data = ["DHL Express", "Fed Ex", "TNT", "Express Mail"]
    var picker = UIPickerView()

    override func viewDidLoad() {
        super.viewDidLoad()
        picker.delegate = self
        picker.dataSource = self
        selectTransportCompany.inputView = picker
    }

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

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

    func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        selectTransportCompany.text = data[row]

    }

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


}

但是，當我運行此代碼時，出現錯誤提示

線程1：EXC_BAD_INSTRUCTION

進入調試器，我得到以下信息：

致命錯誤：解開Optional值時意外發現nil

誰能知道問題所在，我也遵循了本教程 。

Answer 1

您只需要將視圖控制器文本字段出口連接到故事板selectTransportCompany textField。