Swift 使用CollectionView 实现图片轮播封装就是这样简单

Posted 2020-07-30 专注it

前言: 这篇你可以学会自定义视图,创建collectionView,协议的使用,定时器;

自制图片

先上Demo:Github上封装好的下载即用, 好用请Star Thanks
首先新建一个继承于UIView的视图, 且用collectionView实现所以需要签订两个协议代码如下:

let sectionNum: Int = 100 // 区的数量
let width =  UIScreen.mainScreen().bounds.size.width // 屏幕宽度
let height = UIScreen.mainScreen().bounds.size.width // 屏幕高度 
// 因为要实现轮播图片可以点击定义一个协议
// 协议
protocol XTCycleViewDelegate {
    func didSelectIndexCollectionViewCell(index: Int)->Void
}

class XTCycleScrollView: UIView, UICollectionViewDelegate, UICollectionViewDataSource{

使用到的变量以及创建视图

    var delegate: XTCycleViewDelegate?
    var cycleCollectionView: UICollectionView?
    var images = NSMutableArray()
    var pageControl = UIPageControl()
    var flowlayout = UICollectionViewFlowLayout()
    var timer = NSTimer()
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.createSubviews(frame)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

布局必要的UI以及创建定时器

    func createSubviews(frame: CGRect){
        cycleCollectionView = UICollectionView.init(frame: CGRectMake(0, 0, frame.size.width, frame.size.height), collectionViewLayout: flowlayout)
        flowlayout.itemSize = CGSizeMake(frame.size.width, frame.size.height);
        flowlayout.minimumInteritemSpacing = 0;
        flowlayout.minimumLineSpacing = 0;
        flowlayout.scrollDirection = UICollectionViewScrollDirection.Horizontal;
        cycleCollectionView!.backgroundColor = UIColor.lightGrayColor()
        cycleCollectionView!.pagingEnabled = true
        cycleCollectionView!.dataSource  = self
        cycleCollectionView!.delegate = self
        cycleCollectionView!.showsHorizontalScrollIndicator = false
        cycleCollectionView!.showsVerticalScrollIndicator = false
        cycleCollectionView!.registerClass(ZJCustomCycleCell.self, forCellWithReuseIdentifier: "cellId")
        self.addSubview(cycleCollectionView!)
        pageControl = UIPageControl.init(frame: CGRectMake(0, 0, frame.size.width / 2, 30))
        pageControl.center = CGPointMake(frame.size.width / 2, frame.size.height - 20);
        self.addSubview(pageControl);
        self.addTimer()
    }

定时器初始化

func addTimer(){
        let timer1 = NSTimer.init(timeInterval: 2, target: self, selector: "nextPageView", userInfo: nil, repeats: true)
        NSRunLoop.currentRunLoop().addTimer(timer1, forMode: NSRunLoopCommonModes)
        timer = timer1
    }

销毁定时器

func removeTimer(){
        self.timer.invalidate()
    }

实现循环滚动

 func returnIndexPath()->NSIndexPath{
        var currentIndexPath = cycleCollectionView!.indexPathsForVisibleItems().last
        currentIndexPath = NSIndexPath.init(forRow: (currentIndexPath?.row)!, inSection: sectionNum / 2)
        cycleCollectionView!.scrollToItemAtIndexPath(currentIndexPath!, atScrollPosition: UICollectionViewScrollPosition.Left, animated: false)
        return currentIndexPath!;
    }
 func nextPageView(){

        let indexPath = self.returnIndexPath()
        var item = indexPath.row + 1;
        var section = indexPath.section;
        if item == images.count {
            item = 0
            section++
        }
        self.pageControl.currentPage = item;
        let nextIndexPath = NSIndexPath.init(forRow: item, inSection: section)
        cycleCollectionView!.scrollToItemAtIndexPath(nextIndexPath, atScrollPosition: UICollectionViewScrollPosition.Left, animated: true)
    }

collectionView Delegate

     // 重用池
     func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        // 这里使用的自定义cell, 下面会贴出自定义cell代码
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("cellId", forIndexPath: indexPath) as! ZJCustomCycleCell
        // 这个Label实现显示数字,表示是第几张图片
        cell.labelTitle.text = NSString(format: "%d", indexPath.row) as String
        // 这里是图片赋值
        let url:String = self.images[indexPath.row] as! String
        // 这里我使用的是一个赋值图片的三方库,看自己喜好,为方便我没有自己写
        cell.imageView.hnk_setImageFromURL(NSURL.init(string: url)!)
        return cell
    }
    func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
        return sectionNum
    }
    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        // 在这里给出了pageControl的数量
        pageControl.numberOfPages = images.count
        return images.count
    }

    //  重新添加定时器
    func scrollViewDidEndDragging(scrollView: UIScrollView, willDecelerate decelerate: Bool) {
        self.addTimer()
    }
    // 手动滑动的时候销毁定时器
    func scrollViewWillBeginDragging(scrollView: UIScrollView) {
        self.removeTimer()
    }

设置当前的pagecontrol

func scrollViewDidEndDecelerating(scrollView: UIScrollView) {
        let page = (Int(scrollView.contentOffset.x) / Int(width)) % images.count
        pageControl.currentPage = page
    }

点击方法

func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
        self.delegate?.didSelectIndexCollectionViewCell(indexPath.row)
    }

下面是我在自定义cell中的代码

    var urlImage: String = ""
    var imageView = UIImageView()
    var labelTitle = UILabel()
    override init(frame: CGRect) {
        super.init(frame: frame)
        self.createSubviews(frame)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    func createSubviews(frame: CGRect){
        imageView = UIImageView.init(frame: CGRectMake(0, 0, frame.size.width, frame.size.height))
        self.contentView.addSubview(imageView)
        labelTitle = UILabel.init(frame: CGRectMake(10, 10, 30, 30))
        imageView.addSubview(labelTitle)
    }

封装基本完成了, 下面看看如何使用

        // 创建
        let cycle = XTCycleScrollView.init(frame: CGRectMake(0, 70, width, 175))
        // 要实现点击需要制定代理人
        cycle.delegate = self;
        // 图片链接数组
        let images: NSMutableArray = ["", "", "", ""]
        // 数组赋值
        cycle.images = images
        self.view.addSubview(cycle)

实现代理方法

func didSelectIndexCollectionViewCell(index: Int) {
        print("\\(index)")
    }

总结: 这样就实现了简单的图片轮播效果,并且带有点击方法, 都看到这里就点个赞吧. 哈哈

文／夏天然后（简书作者）
原文链接：http://www.jianshu.com/p/f5fa66699a96
著作权归作者所有，转载请联系作者获得授权，并标注“简书作者”。