类方法关键字static

    static func createInterests() -> [CollectionModel] {
        return [
            CollectionModel(title: "Hello there, i miss u.", descriptions: "We love backpack and adventures! We walked to Antartica yesterday, and camped with some cute pinguines, and talked about this wonderful app idea. 🐧⛺️✨", featuredImage: UIImage(named: "hello")!),
            CollectionModel(title: "🐳🐳🐳🐳🐳", descriptions: "We love romantic stories. We walked to Antartica yesterday, and camped with some cute pinguines, and talked about this wonderful app idea. 🐧⛺️✨", featuredImage: UIImage(named: "dudu")!),
        ]
    }

ClassName.self

        collectionView .register(CollectionCell.self, forCellWithReuseIdentifier: reuseIdentifier)

didSet

顾名思义, set方法调用之后调用

var data: CollectionModel? {
        /*属性观察器
         willSet 在新的值被设置之前调用
         didSet 在新的值被设置之后立即调用
         */
        didSet {
            updateUI()
        }
    }

重写Model的init方法

init(title: String, descriptions: String, featuredImage: UIImage) {
        self.title = title
        self.descriptions = descriptions
        self.featuredImage = featuredImage
    }

调用

CollectionModel(title: "Hello there, i miss u.", descriptions: "We love backpack and adventures! We walked to Antartica yesterday, and camped with some cute pinguines, and talked about this wonderful app idea. 🐧⛺️✨", featuredImage: UIImage(named: "hello")!),

extension协议

/*扩展ViewController支持协议*/
extension ViewController: UICollectionViewDataSource, UICollectionViewDelegate {
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1
    }
    
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return data.count
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as! CollectionCell
        
        cell.data = self.data[indexPath.row]
        
        return cell
    }
}

<li><h1>学习代码:<h1></li>

CollectionModel.swift

import UIKit

class CollectionModel: NSObject {
    var title: String?
    var descriptions: String?
    var featuredImage: UIImage?
    
    init(title: String, descriptions: String, featuredImage: UIImage) {
        self.title = title
        self.descriptions = descriptions
        self.featuredImage = featuredImage
    }
    
    static func createInterests() -> [CollectionModel] {
        return [
            CollectionModel(title: "Hello there, i miss u.", descriptions: "We love backpack and adventures! We walked to Antartica yesterday, and camped with some cute pinguines, and talked about this wonderful app idea. 🐧⛺️✨", featuredImage: UIImage(named: "hello")!),
            CollectionModel(title: "🐳🐳🐳🐳🐳", descriptions: "We love romantic stories. We walked to Antartica yesterday, and camped with some cute pinguines, and talked about this wonderful app idea. 🐧⛺️✨", featuredImage: UIImage(named: "dudu")!),
            CollectionModel(title: "Training like this, #bodyline", descriptions: "Create beautiful apps. We walked to Antartica yesterday, and camped with some cute pinguines, and talked about this wonderful app idea. 🐧⛺️✨", featuredImage: UIImage(named: "bodyline")!),
            CollectionModel(title: "I'm hungry, indeed.", descriptions: "Cars and aircrafts and boats and sky. We walked to Antartica yesterday, and camped with some cute pinguines, and talked about this wonderful app idea. 🐧⛺️✨", featuredImage: UIImage(named: "wave")!),
            CollectionModel(title: "Dark Varder, #emoji", descriptions: "Meet life with full presence. We walked to Antartica yesterday, and camped with some cute pinguines, and talked about this wonderful app idea. 🐧⛺️✨", featuredImage: UIImage(named: "darkvarder")!),
            CollectionModel(title: "I have no idea, bitch", descriptions: "Get up to date with breaking-news. We walked to Antartica yesterday, and camped with some cute pinguines, and talked about this wonderful app idea. 🐧⛺️✨", featuredImage: UIImage(named: "hhhhh")!),
        ]
    }
}

CollectionCell.swift

import UIKit

class CollectionCell: UICollectionViewCell {
    
    let featureImageView = UIImageView(frame: CGRect(x: 0.0, y: 0.0, width: ItemWidth, height: ItemHeight))
    let interestTitleLabel = UILabel(frame: CGRect(x: 0.0, y: ItemHeight-50, width: ItemWidth, height: 20))
    let interestDetailLabel = UILabel(frame: CGRect(x: 0.0, y: ItemHeight-30, width: ItemWidth, height: 30))
    var data: CollectionModel? {
        /*属性观察器
         willSet 在新的值被设置之前调用
         didSet 在新的值被设置之后立即调用
         */
        didSet {
            updateUI()
        }
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        interestTitleLabel.backgroundColor = .gray
        interestTitleLabel.textColor = .white
        interestTitleLabel.textAlignment = .center
        interestTitleLabel.font = UIFont.systemFont(ofSize: 16, weight: 4)
        interestDetailLabel.backgroundColor = .white
        interestDetailLabel.backgroundColor = .gray
        interestDetailLabel.textColor = .white
        interestDetailLabel.textAlignment = .center
        interestDetailLabel.numberOfLines = 0
        interestDetailLabel.font = UIFont.systemFont(ofSize: 10)
        contentView.addSubview(featureImageView)
        contentView.addSubview(interestTitleLabel)
        contentView.addSubview(interestDetailLabel)
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    private func updateUI() {
        featureImageView.image = data?.featuredImage
        interestTitleLabel.text = data?.title
        interestDetailLabel.text = data?.descriptions
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        
        self.layer.cornerRadius = 5.0
        featureImageView.clipsToBounds = true
    }
    
}

ViewController.swift

import UIKit

let YHRect = UIScreen.main.bounds
let YHHeight = YHRect.size.height
let YHWidth = YHRect.size.width

let ItemWidth = YHWidth-40.0
let ItemHeight = YHHeight/3.0

class ViewController: UIViewController {
    
    let backgroundImageView = UIImageView(frame: YHRect)
    var collectionView: UICollectionView!
    let data = CollectionModel.createInterests()
    let reuseIdentifier = "CollectionCell"
    let visualEffectView = UIVisualEffectView(effect: UIBlurEffect(style: .light))

    override func viewDidLoad() {
        super.viewDidLoad()
        setupView()
    }
    
    func setupView() {
        backgroundImageView.image = UIImage(named: "blue")
        
        let collectionLayout = UICollectionViewFlowLayout()
        collectionLayout.scrollDirection = .horizontal//滚动方向
        collectionLayout.itemSize = CGSize(width: ItemWidth, height: ItemHeight)//cell大小
        collectionLayout.minimumLineSpacing = 20//上下间隔
        collectionLayout.minimumInteritemSpacing = 20//左右间隔
        collectionLayout.sectionInset = UIEdgeInsets(top: 0, left: 20, bottom: 0, right: 20)//section边界
        collectionView = UICollectionView(frame: CGRect(x: 0.0, y: (YHHeight-ItemHeight)/2, width: YHWidth, height: ItemHeight), collectionViewLayout: collectionLayout)
        collectionView.backgroundColor = .clear
        collectionView.dataSource = self
        collectionView.delegate = self
        collectionView .register(CollectionCell.self, forCellWithReuseIdentifier: reuseIdentifier)
        
        visualEffectView.frame = YHRect
        
        view.addSubview(backgroundImageView)
        view.addSubview(visualEffectView)
        view.addSubview(collectionView)
    }
    
    override var preferredStatusBarStyle: UIStatusBarStyle {
        return .lightContent
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

/*扩展ViewController支持协议*/
extension ViewController: UICollectionViewDataSource, UICollectionViewDelegate {
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1
    }
    
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return data.count
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as! CollectionCell
        
        cell.data = self.data[indexPath.row]
        
        return cell
    }
}