只言片语 - cell 图片复用问题

一、 今日做项目遇到图片复用问题，返回cell高度相同，由于网络不好出现图片复用，发现问题

 

Cell 图片加载方法如下：

- (void)sd_setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder {

    [selfsd_setImageWithURL:url placeholderImage:placeholder options:0progress:nilcompleted:nil];

}

 

更改为：

- (void)sd_setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder options:(SDWebImageOptions)options {

    [selfsd_setImageWithURL:url placeholderImage:placeholder options:options progress:nilcompleted:nil];

}

options 方法如下：

 

    /**

 

     * By default, when a URL fail to be downloaded, the URL is blacklisted so the library won't keep trying.

 

     * This flag disable this blacklisting.

     失败后重新下载

 

     */

 

    SDWebImageRetryFailed = 1 << 0,

    /**

 

     * By default, image downloads are started during UI interactions, this flags disable this feature,

 

     * leading to delayed download on UIScrollView deceleration for instance.

     Scrollview 滑动的时候，或者交互的时候，禁止下载图片，等非滑动时刻开始下载，默认情况下,图片会在交互发生的时候下载(例如你滑动tableview的时候),这个flag会禁止这个特性,导致的结果就是在scrollview减速的时候才会开始下载

 

     */

 

    SDWebImageLowPriority = 1 << 1,

    /**

 

     * This flag disables on-disk caching

     禁止磁盘缓存

 

     */

 

    SDWebImageCacheMemoryOnly = 1 << 2,

    /**

 

     * This flag enables progressive download, the image is displayed progressively during download as a browser would do.

 

     * By default, the image is only displayed once completely downloaded.

     图片逐步下载,这个flag会使图片边下载边显示，不用此方法是下载完成再一次性显示

 

     */

 

    SDWebImageProgressiveDownload = 1 << 3,

    /**

 

     * Even if the image is cached, respect the HTTP response cache control, and refresh the image from remote location if needed.

 

     * The disk caching will be handled by NSURLCache instead of SDWebImage leading to slight performance degradation.

 

     * This option helps deal with images changing behind the same request URL, e.g. Facebook graph api profile pics.

 

     * If a cached image is refreshed, the completion block is called once with the cached image and again with the final image.

 

     *

 

     * Use this flag only if you can't make your URLs static with embedded cache busting parameter.

     更换头像的时候使用 

 

     */

 

    SDWebImageRefreshCached = 1 << 4,

 

 

 

    /**

 

     * In iOS 4+, continue the download of the image if the app goes to background. This is achieved by asking the system for

 

     * extra time in background to let the request finish. If the background task expires the operation will be cancelled.

     返回后台继续下载图片

 

     */

    SDWebImageContinueInBackground = 1 << 5,

    /**

 

     * Handles cookies stored in NSHTTPCookieStore by setting

 

     * NSMutableURLRequest.HTTPShouldHandleCookies = YES;

     使用Cookies的方法

 

     */

    SDWebImageHandleCookies = 1 << 6,

 

    /**

 

     * Enable to allow untrusted SSL certificates.

 

     * Useful for testing purposes. Use with caution in production.

     允许不被信任的SSL证书

 

     */

    SDWebImageAllowInvalidSSLCertificates = 1 << 7,

 

 

 

    /**

 

     * By default, images are loaded in the order in which they were queued. This flag moves them to

 

     * the front of the queue.

     图片下载优先级最高，优先下载图片

 

     */

 

    SDWebImageHighPriority = 1 << 8,

    /**

 

     * By default, placeholder images are loaded while the image is loading. This flag will delay the loading

 

     * of the placeholder image until after the image has finished loading.

     默认情况下,占位图会在图片下载的时候显示.这个flag开启会延迟占位图显示的时间,等到图片下载完成之后才会显示占位图(有何意义？

 

     */

 

    SDWebImageDelayPlaceholder = 1 << 9,

    /**

 

     * We usually don't call transformDownloadedImage delegate method on animated images,

 

     * as most transformation code would mangle it.

 

     * Use this flag to transform them anyway.

     我们通常不会在动画图像上调用transformDownloadedImage委托方法，因为大多数转换代码会对它进行转换，使用此标志来转换它们

 

     */

 

    SDWebImageTransformAnimatedImage = 1 << 10,

 

    /**

 

     * By default, image is added to the imageView after download. But in some cases, we want to

 

     * have the hand before setting the image (apply a filter or add it with cross-fade animation for instance)

 

     * Use this flag if you want to manually set the image in the completion when success

     在图片下载完，显示处理之后的图片

 

     */

 

    SDWebImageAvoidAutoSetImage = 1 << 11