swift - 我试图在单击 TextField 时在 InputView 中显示 DatePicker

Question

每当我尝试此代码时，它都会显示错误

Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value (lldb) 

我尝试了很多解决方案，观看了很多成功视频，但是当我在我的代码中尝试时，它显示了上述错误

import Foundation
import UIKit



class MainNavigationController: UINavigationController {

    @IBOutlet weak var IfFromDate: UITextField!

    @IBOutlet weak var IfToDate: UITextField!
    let datePicker = UIDatePicker()


    override func viewDidLoad() {
        super.viewDidLoad()
        showDatePicker()


    }

    func showDatePicker(){
        //Formate Date

        datePicker.datePickerMode = .date
        IfFromDate.inputView = datePicker //accruing error on this line

    }
    @IBAction func btnSignIn(_ sender: Any) {
    }
}

标签： swiftiphonexcodeuidatepickerunwrap