swift iOS – 快速滚动后混合的UICollectionView图像

我是 swift和iOS编程的新手,但我已经能够在 Xcode中为我的应用程序构建一个基本稳定的启动界面. CollectionView从我家庭网络服务器上的csv文件创建的字典数组中获取图像和文本. cvs文件包含以下格式的数据(注意,已更改URL以保护许可图像)：

csv文件

csv file is @ url https://myserver.com/csv.txt and contains the following

Title";"SeriesImageURL
Title1";"https://licensedimage.com/url1
Title2";"https://licensedimage.com/url2
...
Title1000";"https://licensedimage.com/url1000

问题是当快速滚动CollectionView时,单元格将抓取不正确的图像.值得注意的是,如果您进行慢速或中速滚动,则在将正确的图像渲染到正确的单元格之前将显示不同的图像(单元格的标签文本始终是正确的,只有图像永远关闭).在图像与具有标签的正确单元格不匹配之后,CollectionView中的所有其他单元格也将显示不正确的图像.

例如.单元格1-9将显示具有正确Image1-9的Title1-9
当缓慢滚动时,单元格19-27将显示标题19-27,将简要显示图像10-18,然后显示正确的图像19-27.
当快速滚动大量单元格时(例如从单元格1-9到单元格90-99),单元格90-99将显示标题90-99,将显示图像10-50ish,然后将错误地保留在图像41-50 (或左右).当进一步滚动时,单元格100将显示正确的标题,但仅显示图像41-50范围内的图像.

我认为这个错误或者是因为没有正确处理单元重用,没有正确处理图像的缓存,或者两者兼而有之.它也可能是我作为初学者iOS / swift程序员看不到的东西.我试图用完成修饰符实现一个请求,但似乎无法使我的代码设置方式正常工作.我将不胜感激任何帮助,并解释为什么修复工作的方式.谢谢！

相关代码如下.

SeriesCollectionViewController.swift

class SeriesCollectionViewController: UICollectionViewController,UISearchBarDelegate {

let reuseIdentifier:String = "SeriesCell"

// Set Data Source Models & Variables
struct seriesModel {

    let title: AnyObject
    let seriesimageurl: AnyObject
}
var seriesDict = [String:AnyObject]()
var seriesArray = [seriesModel]()

// Image Cache
var imageCache = NSCache() 

override func viewDidLoad() {
    super.viewDidLoad()
    // Grab Data from Source
    do {

        let url = NSURL(string: "https://myserver.com/csv.txt")
        let fullText = try NSString(contentsOfURL: url!,encoding: NSUTF8StringEncoding)
        let readings = fullText.componentsSeparatedByString("n") as [String]
        var seriesDictCount = readings.count
        seriesDictCount -= 1
        for i in 1..<seriesDictCount {
            let seriesData = readings[i].componentsSeparatedByString("";"")
            seriesDict["Title"] = "(seriesData[0])"
            seriesDict["SeriesImageURL"] = "(seriesData[1])"
            seriesArray.append(seriesModel(
                title: seriesDict["Title"]!,seriesimageurl: seriesDict["SeriesImageURL"]!,))
        }
    } catch let error as NSError {
        print("Error: (error)")
    }
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    imageCache.removeAllObjects()
    // Dispose of any resources that can be recreated.
}

//...
//...skipping over some stuff that isn't relevant
//...

override func collectionView(collectionView: UICollectionView,cellForItemAtIndexPath indexPath: NSIndexPath) -> SeriesCollectionViewCell {
    let cell: SeriesCollectionViewCell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier,forIndexPath: indexPath) as! SeriesCollectionViewCell

    if (self.searchBarActive) {
        let series = seriesArrayForSearchResult[indexPath.row]
        do {
            // set image
            if let imageURL = NSURL(string: "(series.seriesimageurl)") {
                if let image = imageCache.objectForKey(imageURL) as? UIImage {
                        cell.seriesImage.image = image
                } else {
                    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND,0),{
                        if let tvimageData = NSData(contentsOfURL: imageURL) {
                            let image = UIImage(data: tvimageData)
                            self.imageCache.setObject(image!,forKey: imageURL)
                                dispatch_async(dispatch_get_main_queue(),{ () -> Void in
                                    cell.seriesImage.image = nil
                                    cell.seriesImage.image = image
                                })
                        }
                    })
                }
            }
            cell.seriesLabel.text = "(series.title)"
        }
    } else {
        let series = seriesArray[indexPath.row]
        do {
            // set image
            if let imageURL = NSURL(string: "(series.seriesimageurl)") {
                if let image = imageCache.objectForKey(imageURL) as? UIImage {
                        cell.seriesImage.image = image
                } else {
                    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND,forKey: imageURL)
                            dispatch_async(dispatch_get_main_queue(),{ () -> Void in
                                cell.seriesImage.image = nil
                                cell.seriesImage.image = image
                            })
                        }
                    })
                }

            }
            cell.seriesLabel.text = "(series.title)"
        }
    }
    cell.layer.shouldRasterize = true
    cell.layer.rasterizationScale = UIScreen.mainScreen().scale
    cell.prepareForReuse()
    return cell
}

SeriesCollectionViewCell

class SeriesCollectionViewCell: UICollectionViewCell {

@IBOutlet weak var seriesImage: UIImageView!
@IBOutlet weak var seriesLabel: UILabel!

}

let cell: SeriesCollectionViewCell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier,forIndexPath: indexPath) as! SeriesCollectionViewCell

cell.seriesImage.image = UIImage()    //nil

cell.seriesImage.indexPath = indexPath

if cell.seriesImage.indexPath == indexPath
cell.seriesImage.image = image