self sizing modal with airbnb/AloeStackView - issue #41

CustomView.swift

//
//  CustomView.swift
//  AloeStackDemo
//
//  Created by Florian LUDOT on 2/28/19.
//  Copyright © 2019 Florian LUDOT. All rights reserved.
//

import UIKit

class CustomView: UIView {
    
    let label: UILabel = {
        let label = UILabel()
        label.translatesAutoresizingMaskIntoConstraints = false
        label.isUserInteractionEnabled = false
        label.font = UIFont.boldSystemFont(ofSize: 20)
        return label
    }()
    
    override init(frame: CGRect) {
        super.init(frame: .zero)
        
        self.backgroundColor = UIColor.random()
        self.addSubview(label)
        
        NSLayoutConstraint.activate([
            label.centerXAnchor.constraint(equalTo: self.centerXAnchor),
            label.centerYAnchor.constraint(equalTo: self.centerYAnchor),
        ])
        
        NSLayoutConstraint.activate([
            self.heightAnchor.constraint(equalToConstant: 100)
        ])
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
}

ModalPopupView.swift

//
//  ModalPopupView.swift
//  AloeStackDemo
//
//  Created by Florian LUDOT on 2/28/19.
//  Copyright © 2019 Florian LUDOT. All rights reserved.
//

import UIKit
import AloeStackView

class ModalPopupView: UIView {
    
    var aloeStackViewHeightConstraint: NSLayoutConstraint!
    
    let maxHeight: CGFloat = UIScreen.main.bounds.height - 200
    
    let aloeStackView: AloeStackView = {
        let sv = AloeStackView()
        sv.translatesAutoresizingMaskIntoConstraints = false
        sv.rowInset = .zero
        sv.separatorHeight = 0
        sv.backgroundColor = .clear
        return sv
    }()
    
    override init(frame: CGRect) {
        super.init(frame: .zero)
        self.translatesAutoresizingMaskIntoConstraints = false
        self.addSubview(aloeStackView)
        
        aloeStackViewHeightConstraint = aloeStackView.heightAnchor.constraint(equalToConstant: 10)
        aloeStackViewHeightConstraint.isActive = true
        
        NSLayoutConstraint.activate([
            aloeStackView.widthAnchor.constraint(equalToConstant: 260),
        ])
        
        NSLayoutConstraint.activate([
            self.topAnchor.constraint(equalTo: aloeStackView.topAnchor, constant: 0),
            self.leftAnchor.constraint(equalTo: aloeStackView.leftAnchor, constant: 0),
            self.rightAnchor.constraint(equalTo: aloeStackView.rightAnchor, constant: 0),
            self.bottomAnchor.constraint(equalTo: aloeStackView.bottomAnchor, constant: 0),
        ])
        
        setupViews()
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
        
    private func setupViews() {
        let view100 = CustomView()
        view100.label.text = "One row..."
        aloeStackView.addRow(view100)
    }
    
    func resize() {
        aloeStackViewHeightConstraint.constant = min(aloeStackView.contentSize.height, maxHeight)
    }
    
    func push() {
        let view100 = CustomView()
        view100.label.text = "...another row"
        aloeStackView.addRow(view100, animated: true)
    }
    
    func pop() {
        guard let lastRow = aloeStackView.getAllRows().last else { return }
        aloeStackView.removeRow(lastRow, animated: true)
    }
    
}

ModelPopUpViewController.swift

//
//  ModelPopUpViewController.swift
//  AloeStackDemo
//
//  Created by Florian LUDOT on 2/28/19.
//  Copyright © 2019 Florian LUDOT. All rights reserved.
//

import UIKit

class ModalPopoUpViewController: UIViewController {
    
    let modalView = ModalPopupView()

    var numberOfViewsInModal: Double = 1
    
    let stepper: UIStepper = {
        let s = UIStepper()
        s.translatesAutoresizingMaskIntoConstraints = false
        s.minimumValue = 1
        s.maximumValue = 10
        s.stepValue = 1
        s.addTarget(self, action: #selector(valueChanged), for: .valueChanged)
        return s
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.backgroundColor = .lightGray
        
        view.addSubview(modalView)
        view.addSubview(stepper)
        
        NSLayoutConstraint.activate([
            modalView.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0),
            modalView.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: 0)
        ])
        
        NSLayoutConstraint.activate([
            stepper.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0),
            stepper.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 0)
        ])
    }
    
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        modalView.resize()
    }

    @objc private func valueChanged(stepper: UIStepper) {
        stepper.value > numberOfViewsInModal ? modalView.push() : modalView.pop()
        self.numberOfViewsInModal = stepper.value
    }
    
}

UIColor+Extension.swift

//
//  UIColor+Extension.swift
//  AloeStackDemo
//
//  Created by Florian LUDOT on 2/28/19.
//  Copyright © 2019 Florian LUDOT. All rights reserved.
//

import UIKit

extension UIColor {
    
    static func random(withAlpha alpha: CGFloat = 1.0) -> UIColor {
        let r = CGFloat.random(in: 0...1)
        let g = CGFloat.random(in: 0...1)
        let b = CGFloat.random(in: 0...1)
        return UIColor(red: r, green: g, blue: b, alpha: alpha)
    }
    
}