RxSwiftで簡単なPickerView作り

RxSwiftでPickerが簡単に作れる

import RxSwift

class ViewController: UIViewController {

    @IBOutlet private weak var label: UILabel!
    @IBOutlet private weak var textField: UITextField!
    private let pickerView: UIPickerView = UIPickerView()
    private let disposeBag = DisposeBag()

    override func viewDidLoad() {
        super.viewDidLoad()

        setupPicker()
        bind()
    }

    private func setupPicker() {
        textField.inputView = pickerView

        let toolbar = UIToolbar(frame: CGRect(x: 0.0, y: 0.0, width: 0.0, height: 50.0))
        let space = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
        let doneItem = UIBarButtonItem(barButtonSystemItem: .done, target: nil, action: nil)
     
        //完了ボタンを押した時の動作
        doneItem.rx.tap.asDriver()
            .drive(onNext: { [weak self] (_) in
                 self?.textField.endEditing(true)
            }).disposed(by: disposeBag)

        toolbar.setItems([space, doneItem], animated: true)
        textField.inputAccessoryView = toolbar
    }

    private func bind() {
        //Pickerの中に使いたい配列ーここでは1900年〜2021年を配列にしている
        let years = (1900 ..< 2021).map { "\($0)" + "年" }

        Observable.just(years)
            .bind(to: pickerView.rx.itemTitles) { _, year in
                return year
            }.disposed(by: disposeBag)

        pickerView.rx.modelSelected(String.self)
            .map { years in
                return years.first
            }
            .bind(to: label.rx.text)
            .disposed(by: disposeBag)

        //Pickerの初期値ーここでは2000年にしている
        self.pickerView.selectRow(100, inComponent: 0, animated: true)
    }
}