【「ViewController」のコード】
import UIKit
class ViewController: UIViewController,UICollectionViewDelegate,UICollectionViewDataSource,UICollectionViewDelegateFlowLayout {
private let collectionView = UICollectionView(
frame: .zero,
collectionViewLayout: UICollectionViewFlowLayout()
)
override func viewDidLoad() {
super.viewDidLoad()
collectionView.register(PhotoCollectionViewCell.self, forCellWithReuseIdentifier: PhotoCollectionViewCell.identifier)
collectionView.delegate = self
collectionView.dataSource = self
view.addSubview(collectionView)
}
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
collectionView.frame = view.bounds
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 30
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: PhotoCollectionViewCell.identifier, for: indexPath)
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: (view.frame.size.width/3)-3,
height: (view.frame.size.width/3)-3
)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 1
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 1
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsets(top: 1, left: 1, bottom: 1, right: 1)
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
collectionView.deselectItem(at: indexPath, animated: true)
print("Selected section \(indexPath.section) and row \(indexPath.row)")
}
}
【「PhotoCollectionViewCell」のコード】
import UIKit
class PhotoCollectionViewCell: UICollectionViewCell {
static let identifier = "PhotoCollectionViewCell"
private let imageView: UIImageView = {
let imageView = UIImageView()
imageView.contentMode = .scaleAspectFill
imageView.clipsToBounds = true
return imageView
}()
override init(frame: CGRect) {
super.init(frame: frame)
contentView.addSubview(imageView)
let images = [
UIImage(named: "Bar1"),
UIImage(named: "Bar2"),
UIImage(named: "Bar3"),
UIImage(named: "Bar4"),
UIImage(named: "Bar5"),
UIImage(named: "Bar6")
].compactMap({ $0 })
imageView.image = images.randomElement()
}
required init?(coder: NSCoder) {
fatalError()
}
override func layoutSubviews() {
super.layoutSubviews()
imageView.frame = contentView.bounds
}
override func prepareForReuse() {
super.prepareForReuse()
// imageView.image = nil
}
}
参考動画
Create Collection View for Beginners (Swift 5, Xcode 12, iOS) - 2020 iOS Development
https://www.youtube.com/watch?v=_OkriRP8Vx8&t=51s