Attempt to create RxWay PincodeKeyboard

PincodeKeyboard.swift

import UIKit
import RxSwift
import RxCocoa

enum PincodeButtonValue {
    case digit(value: Int)
    case touchId
    case backspace
}

class NewPincodeKeyboard: UIView {
    private var buttonWidth: CGFloat { return 70.0 }
    private var buttonOffset: CGFloat { return 30 }
    private let disposeBag = DisposeBag()
    private let buttons: Array<PincodeButton> = [
        PincodeButton(value: .digit(value: 1)),
        PincodeButton(value: .digit(value: 2)),
        PincodeButton(value: .digit(value: 3)),
        PincodeButton(value: .digit(value: 4)),
        PincodeButton(value: .digit(value: 5)),
        PincodeButton(value: .digit(value: 6)),
        PincodeButton(value: .digit(value: 7)),
        PincodeButton(value: .digit(value: 8)),
        PincodeButton(value: .digit(value: 9)),
        PincodeButton(value: .touchId),
        PincodeButton(value: .digit(value: 0)),
        PincodeButton(value: .backspace)
    ]
    
    private let buttonPressed = PublishSubject<PincodeButtonValue>()
    public lazy var valueEntered = buttonPressed.asObservable()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        setupSubviews()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        
        setupSubviews()
    }
    
    private func setupSubviews() {
        for button in buttons {
            addSubview(button)
            button.value
                .asObservable()
                .subscribe(onNext: { [unowned self] buttonValue in
                    self.buttonPressed.onNext(buttonValue)
                }).disposed(by: disposeBag)
        }
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        
        let keyboardStartX = bounds.width/2 - buttonWidth*3/2 - buttonOffset
        let keyboardStartY: CGFloat = 0
        
        for (index, button) in buttons.enumerated() {
            let item = CGFloat(index % 3)
            let row = CGFloat(index / 3)
            let buttonX = keyboardStartX + item*(buttonWidth + buttonOffset)
            let buttonY = keyboardStartY + row*(buttonWidth + buttonOffset)
            button.frame = CGRect(x: buttonX, y: buttonY, width: buttonWidth, height: buttonWidth)
        }
    }
}

class PincodeButton: UIButton {
    private let _value: PincodeButtonValue
    public let value = PublishSubject<PincodeButtonValue>()
    private let disposeBag = DisposeBag()
    
    init(value: PincodeButtonValue) {
        self._value = value
        super.init(frame: .zero)
        
        bindTap()
    }
    
    required init?(coder aDecoder: NSCoder) {
        self._value = .digit(value: 0)
        super.init(coder: aDecoder)
        
        bindTap()
    }
    
    private func bindTap() {
        rx.tap.bind { [unowned self] _ in
            self.value.onNext(self._value)
        }.disposed(by: disposeBag)
    }
}