Custom contextual menu appears from bottom to top like `UIAlertControllerStyleActionSheet`

UICContextMenu.swift

//
//  ContextMenu.swift
//
//  Created by Onur Işık on 23.04.2019.
//  Copyright © 2019 Coder ACJHP. All rights reserved.
//
import UIKit

protocol UIContextMenuDelegate: AnyObject {
    func contextMenu(_ contextMenu: UICContextMenu?, didSelectAspectRatio ratio: CGFloat)
    func contextMenu(_ contextMenu: UICContextMenu?, didCancelled: Bool)
}

class UICContextMenu: UIView, UIGestureRecognizerDelegate, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {

    private var shadowView: UIView!
    private var contextMenu: UIView!
    private let posiY: CGFloat = 50
    private let contextMenuWidth: CGFloat = 280
    private let contextMenuHeight: CGFloat = 340
    
    private lazy var collectionView: UICollectionView = {
        let flowLayout = UICollectionViewFlowLayout()
        flowLayout.scrollDirection = .vertical
        let collectionView = UICollectionView(frame: .zero, collectionViewLayout: flowLayout)
        collectionView.register(AspectRatioCell.self, forCellWithReuseIdentifier: cellId)
        collectionView.register(ReusableHeaderView.self,
                                forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader,
                                withReuseIdentifier: headerId)
        collectionView.delegate = self
        collectionView.dataSource = self
        collectionView.showsVerticalScrollIndicator = false
        collectionView.showsHorizontalScrollIndicator = false
        collectionView.frame = CGRect(x: 0, y: 0, width: contextMenuWidth, height: contextMenuHeight)
        collectionView.backgroundColor = .clear
        return collectionView
    }()
    
    
    private lazy var keyWindowFrame: CGRect = {
        if let keyWindow = UIApplication.shared.keyWindow {
            return keyWindow.frame
        }
        return .zero
    }()
    
    private lazy var ExpandedRect: CGRect =  {
        return CGRect(x: keyWindowFrame.width / 2 - contextMenuWidth / 2,
                      y: keyWindowFrame.height - contextMenuHeight - posiY,
                      width: contextMenuWidth,
                      height: contextMenuHeight)
    }()
    
    private lazy var CollapsedRect: CGRect =  {
        return CGRect(x: keyWindowFrame.width / 2 - contextMenuWidth / 2,
                      y: keyWindowFrame.height - posiY,
                      width: contextMenuWidth,
                      height: 0)
    }()
    
    private let cellId = "customCellId"
    private let headerId = "customHeaderId"
    private var aspectRatiosList = [
        AspectRatio(kind: .SixtyNine, name: Ratios.SixtyNine.rawValue),
        AspectRatio(kind: .NineSixty, name: Ratios.NineSixty.rawValue),
        AspectRatio(kind: .FourThree, name: Ratios.FourThree.rawValue),
        AspectRatio(kind: .ThreeFour, name: Ratios.ThreeFour.rawValue),
        AspectRatio(kind: .OneOne, name: Ratios.OneOne.rawValue),
        AspectRatio(kind: .Cancel, name: Ratios.Cancel.rawValue)
    ]
    
    public weak var delegate: UIContextMenuDelegate?
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        guard let keyWindow = UIApplication.shared.keyWindow else { return }
        
        shadowView = UIView(frame: keyWindow.bounds)
        shadowView.tag = 1000
        shadowView!.backgroundColor = UIColor.init(white: 0, alpha: 0.5)
        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTap(_:)))
        tapGesture.delegate = self
        shadowView!.addGestureRecognizer(tapGesture)
        keyWindow.addSubview(shadowView!)
        
        contextMenu = UIView(frame: CGRect(x: 0, y: keyWindowFrame.height, width: contextMenuWidth, height: 0))
        contextMenu.backgroundColor = .white
        contextMenu.center.x = keyWindow.center.x
        contextMenu.layer.cornerRadius = 10
        contextMenu.layer.masksToBounds = true
        shadowView.addSubview(contextMenu)
        
        contextMenu.addSubview(collectionView)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    public func showContextMenu() {
        UIView.animate(withDuration: 0.5,
                       delay: 0,
                       usingSpringWithDamping: 1,
                       initialSpringVelocity: 1,
                       options: .curveEaseIn,
                       animations: {
                        
                        self.contextMenu.frame = self.ExpandedRect
                        
        }, completion: nil)
    }
    
    
    @objc private func handleTap(_ gestureRecognizer: UITapGestureRecognizer) {
        
        guard let tappedView = gestureRecognizer.view else { return }
        
        if tappedView.tag == shadowView.tag {
            removeContextMenu()
        }
    }
    
    
    fileprivate func removeContextMenu() {
        
        UIView.transition(with: shadowView,
                          duration: 0.3,
                          options: .curveEaseOut,
                          animations: {
                            
                            self.contextMenu.frame = self.CollapsedRect
                            self.shadowView.alpha = 0
        }) { (_) in
            self.shadowView.removeFromSuperview()
        }
    }
    
    // Best comparition way to detect tapped view (for subviews)
    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
        return touch.view == gestureRecognizer.view
    }
    
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1
    }
    
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return aspectRatiosList.count
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! AspectRatioCell
        cell.aspectRatio = aspectRatiosList[indexPath.item]
        return cell
    }
    
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let selectedCell = collectionView.cellForItem(at: indexPath) as! AspectRatioCell

        UIView.transition(with: self,
                          duration: 0.15,
                          options: .transitionCrossDissolve,
                          animations: {
                            selectedCell.nameLabel.textColor = .white
                            selectedCell.backgroundColor = .lightGray
                            
        }, completion: {[weak self] (_)  in
          
            switch selectedCell.aspectRatio.kind {
            case .SixtyNine?:
                self?.delegate?.contextMenu(self, didSelectAspectRatio: 16/9)
            case .NineSixty?:
                self?.delegate?.contextMenu(self, didSelectAspectRatio: 9/16)
            case .FourThree?:
                self?.delegate?.contextMenu(self, didSelectAspectRatio: 4/3)
            case .ThreeFour?:
                self?.delegate?.contextMenu(self, didSelectAspectRatio: 3/4)
            case .OneOne?:
                self?.delegate?.contextMenu(self, didSelectAspectRatio: 1/1)
            default:
                self?.delegate?.contextMenu(self, didCancelled: true)
            }
            self?.removeContextMenu()
            
        })
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 0
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return 0
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: contextMenuWidth, height: contextMenuHeight / CGFloat(aspectRatiosList.count) - 12)
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        return .init(top: 10, left: 0, bottom: 0, right: 0)
    }
    
    func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
        let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionView.elementKindSectionHeader,
                                                                         withReuseIdentifier: headerId, for: indexPath)
        return headerView
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
        return .init(width: contextMenuWidth, height: 60)
    }
}

enum Ratios: String {
    case SixtyNine = "16 : 9"
    case NineSixty = "9 : 16"
    case FourThree = "4 : 3"
    case ThreeFour = "3 : 4"
    case OneOne = "1 : 1"
    case Cancel = "CANCEL"
}

struct AspectRatio {
    var kind: Ratios!
    var name: String?
}

class ReusableHeaderView: UICollectionReusableView {
    
    private var label = UILabel()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        label = UILabel(frame: .zero)
        label.textColor = .black
        label.text = "Choose aspect ratio for crop"
        label.textAlignment = .center
        label.numberOfLines = 0
        label.font = UIFont.boldSystemFont(ofSize: 17)
        label.translatesAutoresizingMaskIntoConstraints = false
        addSubview(label)
        
        let borderLine = UIView()
        borderLine.backgroundColor = .lightGray
        borderLine.translatesAutoresizingMaskIntoConstraints = false
        addSubview(borderLine)
        
        NSLayoutConstraint.activate([
            label.leadingAnchor.constraint(equalTo: leadingAnchor),
            label.trailingAnchor.constraint(equalTo: trailingAnchor),
            label.topAnchor.constraint(equalTo: topAnchor),
            label.bottomAnchor.constraint(equalTo: bottomAnchor),
            
            borderLine.leadingAnchor.constraint(equalTo: leadingAnchor),
            borderLine.trailingAnchor.constraint(equalTo: trailingAnchor),
            borderLine.heightAnchor.constraint(equalToConstant: 1),
            borderLine.bottomAnchor.constraint(equalTo: bottomAnchor)
       ])
        
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

class AspectRatioCell: UICollectionViewCell {
    
    var aspectRatio: AspectRatio! {
        didSet {
            nameLabel.text = aspectRatio.name
            if aspectRatio.name == Ratios.Cancel.rawValue {
                nameLabel.textColor = .red
            }
        }
    }
    
    var nameLabel = UILabel()
    private var seperatorLine = UIView()
    private lazy var darkestGray = UIColor.init(white: 0.30, alpha: 1.0)
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        nameLabel = UILabel(frame: .zero)
        nameLabel.textColor = .black
        nameLabel.textAlignment = .center
        nameLabel.font = UIFont.boldSystemFont(ofSize: 20)
        nameLabel.translatesAutoresizingMaskIntoConstraints = false
        addSubview(nameLabel)
        
        seperatorLine.backgroundColor = .lightGray
        seperatorLine.translatesAutoresizingMaskIntoConstraints = false
        addSubview(seperatorLine)
        
        NSLayoutConstraint.activate([
            nameLabel.leadingAnchor.constraint(equalTo: leadingAnchor),
            nameLabel.trailingAnchor.constraint(equalTo: trailingAnchor),
            nameLabel.topAnchor.constraint(equalTo: topAnchor),
            nameLabel.bottomAnchor.constraint(equalTo: bottomAnchor),
            
            seperatorLine.leadingAnchor.constraint(equalTo: leadingAnchor),
            seperatorLine.trailingAnchor.constraint(equalTo: trailingAnchor),
            seperatorLine.heightAnchor.constraint(equalToConstant: 0.5),
            seperatorLine.bottomAnchor.constraint(equalTo: bottomAnchor)
        ])
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

How to use?

//  Created by Onur Işık on 23.04.2019.
//  Copyright © 2019 Coder ACJHP. All rights reserved.
//

import UIKit

class TestViewController: UIViewController, UIContextMenuDelegate {

    private var contextMenu: UICContextMenu!
    
    override func viewDidLoad() {
        super.viewDidLoad()

        contextMenu = UICContextMenu(frame: .zero)
        contextMenu.delegate = self
        contextMenu.showContextMenu()
    }
    
    func contextMenu(_ contextMenu: UICContextMenu?, didSelectAspectRatio ratio: CGFloat) {
        print(ratio)
    }
    
    func contextMenu(_ contextMenu: UICContextMenu?, didCancelled: Bool) {
        print(didCancelled)
    }
}