DynamicCellSizing

DynamicCellSizing.swift

//
//  ViewController.swift
//  CollectionViewPractice
//
//  Created by nTom on 2020/10/26.
//  Copyright © 2020 CollectionViewPractice. All rights reserved.
//

import UIKit
import SnapKit

final class ViewController: UIViewController {

    @IBOutlet private weak var collectionView: UICollectionView!
    
    private let items: [String] = [
        "또띠아",
        "버터",
        "달걀",
        "치즈볼",
        "쪽파",
        "진미채",
        "참외",
        "케이크",
        "새우",
        "대패삼겹살",
    ]
    
    override func viewDidLoad() {
        super.viewDidLoad()

        setupView()
    }
    
    private func setupView() {
        view.backgroundColor = .white
        setupCollectionView()
    }
    
    private func setupCollectionView() {
        let flowLayout = UICollectionViewFlowLayout()
        flowLayout.minimumLineSpacing = .zero
        flowLayout.minimumInteritemSpacing = 16
        flowLayout.scrollDirection = .horizontal
        flowLayout.sectionInset = .init(top: 5, left: 16, bottom: 5, right: 16)
        
        collectionView.setCollectionViewLayout(flowLayout, animated: false)
        collectionView.delegate = self
        collectionView.dataSource = self
        collectionView.backgroundColor = .white
        collectionView.register(CollectionViewCell.self, forCellWithReuseIdentifier: "CollectionViewCell")
    }
    
}


extension ViewController: UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
    
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return items.count
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CollectionViewCell", for: indexPath) as! CollectionViewCell
        cell.configure(name: items[indexPath.item])
        return cell
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CollectionViewCell.fittingSize(availableHeight: 45, name: items[indexPath.item])
    }
    
}

final class CollectionViewCell: UICollectionViewCell {
    
    static func fittingSize(availableHeight: CGFloat, name: String?) -> CGSize {
        let cell = CollectionViewCell()
        cell.configure(name: name)
        
        let targetSize = CGSize(width: UIView.layoutFittingCompressedSize.width, height: availableHeight)
        return cell.contentView.systemLayoutSizeFitting(targetSize, withHorizontalFittingPriority: .fittingSizeLevel, verticalFittingPriority: .required)
    }
    
    private let titleLabel: UILabel = UILabel()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setupView()
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        setupView()
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        layer.cornerRadius = frame.height / 2
    }
    
    private func setupView() {
        backgroundColor = .black
        titleLabel.textAlignment = .center
        titleLabel.textColor = .white
        
        contentView.addSubview(titleLabel)
        titleLabel.snp.makeConstraints { (make) in
            make.edges.equalToSuperview().inset(15)
        }
    }
    
    func configure(name: String?) {
        titleLabel.text = name
    }
    
}