UIDatePicker with UIToolbar example.

DatePickerWithToolbar.swift

import UIKit
import PlaygroundSupport

class MyViewController: UIViewController {
    
    let containerView = UIView()
    let datePicker = UIDatePicker()
    
    let toolbar: UIToolbar = {
        let toolbar = UIToolbar()
        let doneButton = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(didTapDoneButton))
        let cancelButton = UIBarButtonItem(barButtonSystemItem: .cancel, target: self, action: #selector(didTapCancelButton))
        toolbar.items = [doneButton, cancelButton]
        toolbar.isUserInteractionEnabled = true
        return toolbar
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .lightGray
        datePicker.backgroundColor = .white
        setupConstraints()
    }
    
    private func setupConstraints() {
        containerView.translatesAutoresizingMaskIntoConstraints = false
        toolbar.translatesAutoresizingMaskIntoConstraints = false
        datePicker.translatesAutoresizingMaskIntoConstraints = false
        
        view.addSubview(containerView)
        containerView.addSubview(toolbar)
        containerView.addSubview(datePicker)
        
        NSLayoutConstraint.activate([
            containerView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            containerView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            containerView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            containerView.heightAnchor.constraint(equalTo: view.heightAnchor, multiplier: 0.5),
            toolbar.topAnchor.constraint(equalTo: containerView.topAnchor),
            toolbar.leadingAnchor.constraint(equalTo: containerView.leadingAnchor),
            toolbar.trailingAnchor.constraint(equalTo: containerView.trailingAnchor),
            toolbar.heightAnchor.constraint(equalToConstant: 50.0),
            datePicker.topAnchor.constraint(equalTo: toolbar.bottomAnchor),
            datePicker.leadingAnchor.constraint(equalTo: containerView.leadingAnchor),
            datePicker.trailingAnchor.constraint(equalTo: containerView.trailingAnchor),
            datePicker.bottomAnchor.constraint(equalTo: containerView.bottomAnchor)
        ])
    }
    
    @objc func didTapDoneButton() {
        print("DoneButton tapped")
    }
    
    @objc func didTapCancelButton() {
        print("CancelButton tapped")
    }
}

PlaygroundPage.current.liveView = MyViewController()