很多时候为了防止app显示图片重复下载，从而节约用户的流量，我们会考虑将下载好的一部分图片保存在本地，在OC中我们可以使用SDWebImage来实现自己的缓存机制，在SWIFT中我们也可以使用相应的第三方库Kingfisher来实现自己的缓存机制。
首先确定图片缓存到Disk的路劲，在Kingfisher中我们可以用
//缓存路径
let imageCache = ImageCache(name: "myImageSpace")
自定义缓存路劲，一般来说，如果我们不对cache进行定义
let cache = KingfisherManager.sharedManager.cache
那么默认的可以储存的图片为无限 默认时间是一周，以上两项属性可以通过****cache.maxDiskCacheSize****和****maxCachePeriodInSecond****来进行设置
这里附带一个获取缓存大小的方法
// 获取硬盘缓存的大小cache.cache.calculateDiskCacheSizeWithCompletionHandler { (size) -> () in println("disk size in bytes: \(size)")}
这里主要涉及到的是缓存管理类ImageCache，demo
public init(name: String, path: String? = nil) {
if name.isEmpty {
fatalError("[Kingfisher] You should specify a name for the cache. A cache with empty name is not permitted.")
}
let cacheName = "com.onevcat.Kingfisher.ImageCache.\(name)"
memoryCache.name = cacheName
let dstPath = path ?? NSSearchPathForDirectoriesInDomains(.cachesDirectory, .userDomainMask, true).first!
diskCachePath = (dstPath as NSString).appendingPathComponent(cacheName)
let ioQueueName = "com.onevcat.Kingfisher.ImageCache.ioQueue.\(name)"
ioQueue = DispatchQueue(label: ioQueueName)
let processQueueName = "com.onevcat.Kingfisher.ImageCache.processQueue.\(name)"
processQueue = DispatchQueue(label: processQueueName, attributes: .concurrent)
ioQueue.sync { fileManager = FileManager() }
#if !os(macOS) && !os(watchOS)
NotificationCenter.default.addObserver(
self, selector: #selector(clearMemoryCache), name: .UIApplicationDidReceiveMemoryWarning, object: nil)
NotificationCenter.default.addObserver(
self, selector: #selector(cleanExpiredDiskCache), name: .UIApplicationWillTerminate, object: nil)
NotificationCenter.default.addObserver(
self, selector: #selector(backgroundCleanExpiredDiskCache), name: .UIApplicationDidEnterBackground, object: nil)
#endif
}
判断该路径下是否有相应的图片
open func retrieveImageInDiskCache(forKey key: String, options: KingfisherOptionsInfo? = nil) -> Image? {
let options = options ?? KingfisherEmptyOptionsInfo
let computedKey = key.computedKey(with: options.processor.identifier)
return diskImage(forComputedKey: computedKey, serializer: options.cacheSerializer, options: options)
}
如果不存在image，获取该image,并存入本地磁盘，返回所需数据
KingfisherManager.shared.downloader.downloadImage(with: URL(string: urlString)!, options: nil, progressBlock: {(receivedSize, totalSize) in
}, completionHandler: {(_ image: Image?, _ error: NSError?, _ url: URL?, _ originalData: Data?) in
guard image != nil else {
print("获取图片失败")
return
}
//存入本地磁盘
imageCache.store(image!, forKey: urlString)
//返回数据
image1 = image
})
当然还有清楚缓存
//清楚缓存
//imageCache.clearDiskCache()
Kingfisher还提供了综合操作的相关方法，可以直接使用
KingfisherManager.shared.retrieveImage(with: <#T##Resource#>, options: <#T##KingfisherOptionsInfo?#>, progressBlock: <#T##DownloadProgressBlock?##DownloadProgressBlock?##(Int64, Int64) -> ()#>, completionHandler: <#T##CompletionHandler?##CompletionHandler?##(Image?, NSError?, CacheType, URL?) -> ()#>)
当然最简单的直接用
imageVeiw.kf.setImage(with: ImageResource(downloadURL:URL(string: (model.image)!)!))
哈哈，这个最重要
