swift_06_Carousel Effect

知识点

1.UICollectionView的使用

2.横向滚动

完整代码

ViewController.swift

import UIKit

class ViewController: UIViewController {

    fileprivate var interests = Interest.createInterests()
  
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        initView()
    }

    fileprivate struct My {
        static let CellIdentifier = "InterestCell"
        static let CellPadding: CGFloat = 16.0
    }
  
    func initView(){
        var collectionView : UICollectionView?
        let layout = UICollectionViewFlowLayout()
  
        layout.sectionInset = UIEdgeInsets(top: 0, left: 5, bottom: 0, right: 5);
        layout.minimumInteritemSpacing = 5; // this number could be anything <=5. Need it here because the default is 10.
        layout.minimumLineSpacing = 4.0 //设置行间距
        layout.itemSize = CGSize(width: 100, height: 44)
        layout.scrollDirection = .horizontal//横向滚动
        collectionView = UICollectionView(frame:CGRect(x: 16, y: 100, width: UIScreen.main.bounds.width-16, height: 450), collectionViewLayout: layout)
        //注册一个cell
        collectionView!.register(InterestCollectionViewCell.self, forCellWithReuseIdentifier:My.CellIdentifier)
        collectionView?.delegate = self;
        collectionView?.dataSource = self;
        collectionView?.backgroundColor = UIColor.gray
        
        collectionView?.showsHorizontalScrollIndicator = true
        collectionView?.showsVerticalScrollIndicator = false
        collectionView?.isPagingEnabled = true
        
        self.view.addSubview(collectionView!)
 
    }
}




extension ViewController : UICollectionViewDataSource {
    
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1
    }
    
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return interests.count
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: My.CellIdentifier, for: indexPath) as! InterestCollectionViewCell
        
        cell.interest = self.interests[indexPath.item]
        
        return cell
        
    }
    
}


extension ViewController : UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: UIScreen.main.bounds.width - 2 * My.CellPadding, height: 450)
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return  My.CellPadding
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        return UIEdgeInsets(top: 0, left: My.CellPadding/2, bottom: 0, right: My.CellPadding)
    }
}
extension ViewController : UIScrollViewDelegate {
    func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
        let originPoint = targetContentOffset.pointee;
        var index = Int(originPoint.x / UIScreen.main.bounds.width)
        let offset = Int(originPoint.x) % Int(UIScreen.main.bounds.width)
        index += (offset > Int(UIScreen.main.bounds.width/2) ? 1 : 0)
        targetContentOffset.pointee = CGPoint(x: index * Int(UIScreen.main.bounds.width) , y: 0)
    }

}

 

数据相关Interest.swift

import UIKit

class Interest {

    // MARK: - Public API
    var title = ""
    var description = ""
    var numberOfMembers = 0
    var numberOfPosts = 0
    var featuredImage: UIImage!
    
    
    init(title: String, description: String, featuredImage: UIImage!)
    {
        self.title = title
        self.description = description
        self.featuredImage = featuredImage
        numberOfMembers = 1
        numberOfPosts = 1
    }
    
    // MARK: - Private
    // dummy data
    static func createInterests() -> [Interest]
    {
        return [
            Interest(title: "Hello there, i miss u.", description: "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")!),
            Interest(title: "🐳🐳🐳🐳🐳", description: "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")!),
            Interest(title: "Training like this, #bodyline", description: "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")!),
            Interest(title: "I'm hungry, indeed.", description: "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")!),
            Interest(title: "Dark Varder, #emoji", description: "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")!),
            Interest(title: "I have no idea, bitch", description: "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")!),
        ]
    }
}

 

自定义cell之 InterestCollectionViewCell.swift

import UIKit

class InterestCollectionViewCell: UICollectionViewCell {
    
    
    var interest: Interest! {
        didSet {
            updateUI()
        }
    }
    
    var titleLabel:UILabel?//title
    var featuredImageView: UIImageView!
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        initView()
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    func initView(){
        titleLabel = UILabel(frame: CGRect(x: 0, y: 300, width: frame.width, height: 44))
        titleLabel?.layer.cornerRadius = 4
        titleLabel?.layer.borderWidth = 0.5
        titleLabel?.textAlignment = NSTextAlignment.center
        titleLabel?.layoutMargins = UIEdgeInsets(top:0, left:0, bottom:0, right:0)
        
        self .addSubview(titleLabel!)
        
        
        featuredImageView = UIImageView(frame: CGRect(x: 0, y: 0, width: frame.width, height: 280))
        
        
        self .addSubview(featuredImageView!)
    }
    
    fileprivate func updateUI() {
        
        titleLabel?.text = interest.title
        featuredImageView?.image = interest.featuredImage
    }
}