用UICollectionView实现上下轮播的案例

//

//  RecommendNewsCell.swift

//  XMLYFM

//

//  Created by Domo on 2018/8/2.

//  Copyright © 2018年 知言网络. All rights reserved.

//

import UIKit

class RecommendNewsCell: UICollectionViewCell {

private var topBuzz:[TopBuzzModel]?

private lazy var imageView : UIImageView = {

let imageView = UIImageView()

imageView.image = UIImage(named: "news.png")

return imageView

}()

private var moreBtn:UIButton = {

let button = UIButton.init(type: UIButtonType.custom)

button.setTitle("|  更多", for: UIControlState.normal)

button.setTitleColor(UIColor.gray, for: UIControlState.normal)

button.titleLabel?.font = UIFont.systemFont(ofSize: 15)

return button

}()

private lazy var collectionView: UICollectionView = {

let layout = UICollectionViewFlowLayout.init()

layout.sectionInset = UIEdgeInsetsMake(0, 0, 0, 0)

layout.minimumInteritemSpacing = 0

layout.minimumLineSpacing = 0

layout.itemSize = CGSize(width: (YYScreenWidth-150), height:40)

let collectionView = UICollectionView.init(frame:CGRect(x:80,y:5, width:YYScreenWidth-150, height:40), collectionViewLayout: layout)

layout.scrollDirection = UICollectionViewScrollDirection.vertical

collectionView.contentSize = CGSize(width: (YYScreenWidth-150), height: 40)

collectionView.delegate = self

collectionView.dataSource = self

collectionView.backgroundColor = UIColor.white

collectionView.showsVerticalScrollIndicator = false

collectionView.showsHorizontalScrollIndicator = false

collectionView.isPagingEnabled = true

collectionView.isScrollEnabled = false

collectionView.register(NewsCell.self, forCellWithReuseIdentifier:"NewsCell")

return collectionView

}()

var timer: Timer?

override init(frame: CGRect) {

super.init(frame: frame)

setUpUI()

// 开启定时器

starTimer()

}

func setUpUI(){

self.addSubview(self.imageView)

self.imageView.snp.makeConstraints { (make) in

make.left.equalToSuperview().offset(10)

make.width.equalTo(60)

make.height.equalTo(30)

make.top.equalTo(10)

}

self.addSubview(self.moreBtn)

self.moreBtn.snp.makeConstraints { (make) in

make.right.equalToSuperview().offset(-5)

make.width.equalTo(60)

make.height.equalTo(40)

make.top.equalTo(5)

}

self.addSubview(self.collectionView)

}

var topBuzzList:[TopBuzzModel]? {

didSet{

guard let model = topBuzzList else { return }

self.topBuzz = model

self.collectionView.reloadData()

}

}

required init?(coder aDecoder: NSCoder) {

super.init(coder: aDecoder)

}

}

extension RecommendNewsCell : UICollectionViewDelegate, UICollectionViewDataSource {

func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {

return (self.topBuzz?.count ?? 0)*100

}

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

let cell:NewsCell = collectionView.dequeueReusableCell(withReuseIdentifier: "NewsCell", for: indexPath) as! NewsCell

cell.titleLabel.text = self.topBuzzList?[indexPath.row%(self.topBuzz?.count)!].title

return cell

}

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {

print(indexPath.row%(self.topBuzz?.count)!)

}

/// 开启定时器

func starTimer () {

let timer = Timer.init(timeInterval: 2, target: self, selector: #selector(nextPage), userInfo: nil, repeats: true)

// 这一句代码涉及到runloop 和 主线程的知识,则在界面上不能执行其他的UI操作

RunLoop.main.add(timer, forMode: RunLoopMode.commonModes)

self.timer = timer

}

/// 在1秒后,自动跳转到下一页

@objc func nextPage() {

// 1.获取collectionView的X轴滚动的偏移量

let currentOffsetY = collectionView.contentOffset.y

let offsetY = currentOffsetY + collectionView.bounds.height

// 2.滚动该位置

collectionView.setContentOffset(CGPoint(x: 0, y: offsetY), animated: true)

}

/// 当collectionView开始拖动的时候,取消定时器

func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {

self.timer?.invalidate()

self.timer = nil

}

/// 当用户停止拖动的时候,开启定时器

func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {

starTimer()

}

}

class NewsCell: UICollectionViewCell {

lazy var titleLabel : UILabel = {

let label = UILabel()

label.font = UIFont.systemFont(ofSize: 16)

return label

}()

override init(frame: CGRect) {

super.init(frame: frame)

self.addSubview(self.titleLabel)

self.titleLabel.snp.makeConstraints { (make) in

make.left.right.height.top.equalToSuperview()

}

}

required init?(coder aDecoder: NSCoder) {

super.init(coder: aDecoder)

}

}