swift中使用UIColllectionView实现横向轮播的一般方法

//

//  HomeLiveRankCell.swift

//  YYSwiftProject

//

//  Created by Domo on 2018/7/28.

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

//

import UIKit

class HomeLiveRankCell: UICollectionViewCell {

private var multidimensionalRankVosList: [MultidimensionalRankVosModel]?

private let LiveRankCellID = "LiveRankCell"

// MARK: - 滚动排行榜

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-30), height:self.frame.size.height)

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

layout.scrollDirection = UICollectionViewScrollDirection.horizontal

let collectionView = UICollectionView.init(frame:.zero, collectionViewLayout: layout)

collectionView.contentSize = CGSize(width: (YYScreenWidth-30), height: self.frame.size.height)

collectionView.delegate = self

collectionView.dataSource = self

collectionView.backgroundColor = UIColor.white

collectionView.showsVerticalScrollIndicator = false

collectionView.showsHorizontalScrollIndicator = false

collectionView.isPagingEnabled = true

collectionView.register(LiveRankCell.self, forCellWithReuseIdentifier:LiveRankCellID)

return collectionView

}()

var timer: Timer?

override init(frame: CGRect) {

super.init(frame: frame)

self.backgroundColor = UIColor.white

self.addSubview(self.collectionView)

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

make.width.height.equalToSuperview()

make.center.equalToSuperview()

}

// 开启定时器

starTimer()

}

required init?(coder aDecoder: NSCoder) {

super.init(coder: aDecoder)

}

// 界面赋值并刷新

var multidimensionalRankVos:[MultidimensionalRankVosModel]? {

didSet {

guard let model = multidimensionalRankVos else { return }

self.multidimensionalRankVosList = model

self.collectionView.reloadData()

}

}

}

extension HomeLiveRankCell: UICollectionViewDataSource, UICollectionViewDelegate {

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

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

}

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

let cell:LiveRankCell = collectionView.dequeueReusableCell(withReuseIdentifier: LiveRankCellID, for: indexPath) as! LiveRankCell

cell.backgroundColor = UIColor.init(red: 248/255.0, green: 245/255.0, blue: 246/255.0, alpha: 1)

cell.multidimensionalRankVos = self.multidimensionalRankVosList?[indexPath.row%(self.multidimensionalRankVosList?.count)!]

return cell

}

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

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

}

/// 开启定时器

func starTimer () {

let timer = Timer.init(timeInterval: 3, 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 currentOffsetX = collectionView.contentOffset.x

let offsetX = currentOffsetX + collectionView.bounds.width

// 2.滚动该位置

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

}

//    // 监听collectionView的滚到

//    func scrollViewDidScroll(_ scrollView: UIScrollView) {

//        // 1、获取滚动的偏移量 + scrollView.bounds.width * 0.5给偏移量加一半，当滑动一般就滚动pageControl的当前选中

//        let offsetX = scrollView.contentOffset.x + scrollView.bounds.width * 0.5

//        // 2、计算pageContra的currentIndex。这 % (cycleModelArr?.count ?? 1)也是跟上同样道理

//        pageControl.currentPage = Int(offsetX / scrollView.bounds.width) % (imageArray?.count ?? 1)

//    }

//

/// 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()

}

}

//

//  LiveRankCell.swift

//  YYSwiftProject

//

//  Created by Domo on 2018/7/28.

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

//

import UIKit

class LiveRankCell: UICollectionViewCell {

private lazy var imageView : UIView = {

let imageView = UIView()

return imageView

}()

private lazy var titleLabel : UILabel = {

let label = UILabel()

label.font = UIFont.systemFont(ofSize: 18)

return label

}()

private lazy var label : UILabel = {

let label = UILabel()

label.text = ">"

label.textColor = UIColor.lightGray

return label

}()

override init(frame: CGRect) {

super.init(frame: frame)

self.addSubview(self.titleLabel)

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

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

make.height.equalTo(40)

make.width.equalTo(100)

make.centerY.equalToSuperview()

}

self.addSubview(self.imageView)

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

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

make.top.equalToSuperview().offset(5)

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

make.width.equalTo(180)

}

self.imageView.addSubview(self.label)

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

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

make.height.width.equalTo(10)

make.centerY.equalToSuperview()

}

}

required init?(coder aDecoder: NSCoder) {

super.init(coder: aDecoder)

}

var multidimensionalRankVos:MultidimensionalRankVosModel? {

didSet {

guard let model = multidimensionalRankVos else { return }

self.titleLabel.text = model.dimensionName

let num:Int = (model.ranks?.count)!

let margin:CGFloat = 50

for index in 0..<num {

let picView = UIImageView.init(frame: CGRect(x:margin*CGFloat(index)+5*CGFloat(index),y:5,width:margin,height:margin))

picView.layer.masksToBounds = true

picView.layer.cornerRadius = picView.frame.size.width/2

picView.kf.setImage(with: URL(string: (model.ranks?[index].coverSmall!)!))

self.imageView.addSubview(picView)

}

}

}

}