Open UIDatePicker programmatically in iOS 14

Question

I have this normal UIDatePicker (sorry that it\'s not in English, please ignore that):

Answer 1

The GraphicalDatePickerStyle in SwiftUI seems to be that second picker that appears after you click on the compact picker.

You should be able to use the UIViewController below in a storyboard object and show the calendar.

class GraphicalDateViewController: UIViewController{
    var datepicker: UIHostingController<CusDatePicker>? = nil
    var dateVM: DatePickerViewModel = DatePickerViewModel()
    
    private var dateCancellable: AnyCancellable?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        //Add Picker
        datepicker = UIHostingController(rootView: CusDatePicker(vm: dateVM))
        let idealSize = datepicker!.sizeThatFits(in: self.view.frame.size)
        datepicker?.view.frame = CGRect(origin: CGPoint(x: self.view.frame.midX - idealSize.width/2, y: self.view.frame.midY - idealSize.height/2), size: idealSize)
        //datepicker?.view.frame = CGRect(origin: CGPoint(x: self.view.frame.midX - 140, y: self.view.frame.midY - 140), size: CGSize(width: 280, height: 280))
        addChild(datepicker!)
        view.addSubview(datepicker!.view)
        
        dateCancellable = dateVM.$currentDate.sink { currentDate in
            self.render(currentDate: currentDate)
        }
    }
    
    // MARK: DatePickerViewModel
    private func render(currentDate: Date) {
        print("GraphicalDateViewController" + #function)
        print(currentDate.description)
    }
}

class DatePickerViewModel: ObservableObject {
    @Published var currentDate: Date = Date()
}
struct CusDatePicker: View {
    @ObservedObject var vm: DatePickerViewModel
    var body: some View {
        //https://developer.apple.com/documentation/swiftui/datepicker
        DatePicker("Date", selection: $vm.currentDate, displayedComponents: [.date, .hourAndMinute])
            .datePickerStyle(GraphicalDatePickerStyle())
    }
}

Answer 2

I don't know if this is still valid, but you can make use of the .inline style of new UIDatePicker. Then use your own view and animations to mimic the appearance of the DatePicker from .compact style.

        let secondDatePicker = UIDatePicker()
        secondDatePicker.preferredDatePickerStyle = .inline
        self.view.addSubview(secondDatePicker)
        
        secondDatePicker.translatesAutoresizingMaskIntoConstraints = false
        secondDatePicker.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        secondDatePicker.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true

Answer 3

If you want to continue using the wheels format, you can set the style to wheels on the story board,

or use this code

datePicker.preferredDatePickerStyle = .wheels