这个分类是给 UIImageView 针对不同的情况添加 UIImage。
.h
下面是 UIImageView 可以使用的不同的加载图片的方式:
1 /** 2 * Set the imageView `image` with an `url`. 3 * 4 * The download is asynchronous and cached. 5 * 6 * @param url The url for the image. 7 */ 8 - (void)sd_setImageWithURL:(nullable NSURL *)url;
根据 url 异步下载和缓存 image，并把返回的 image 赋给 UIImageView。
1 /** 2 * Set the imageView `image` with an `url` and a placeholder. 3 * 4 * The download is asynchronous and cached. 5 * 6 * @param url The url for the image. 7 * @param placeholder The image to be set initially, until the image request finishes. 8 * @see sd_setImageWithURL:placeholderImage:options: 9 */ 10 - (void)sd_setImageWithURL:(nullable NSURL *)url 11 placeholderImage:(nullable UIImage *)placeholder;
先用一个占位图片给 UIImageView 赋图，当图片下载完毕再用返回的图片把占位图替换了。
1 /** 2 * Set the imageView `image` with an `url`, placeholder and custom options. 3 * 4 * The download is asynchronous and cached. 5 * 6 * @param url The url for the image. 7 * @param placeholder The image to be set initially, until the image request finishes. 8 * @param options The options to use when downloading the image. @see SDWebImageOptions for the possible values. 9 */ 10 - (void)sd_setImageWithURL:(nullable NSURL *)url 11 placeholderImage:(nullable UIImage *)placeholder 12 options:(SDWebImageOptions)options;
添加一个下载选项 options。
1 /** 2 * Set the imageView `image` with an `url`. 3 * 4 * The download is asynchronous and cached. 5 * 6 * @param url The url for the image. 7 * @param completedBlock A block called when operation has been completed. This block has no return value 8 * and takes the requested UIImage as first parameter. In case of error the image parameter 9 * is nil and the second parameter may contain an NSError. The third parameter is a Boolean 10 * indicating if the image was retrieved from the local cache or from the network. 11 * The fourth parameter is the original image url. 12 */ 13 - (void)sd_setImageWithURL:(nullable NSURL *)url 14 completed:(nullable SDExternalCompletionBlock)completedBlock;
只有两个参数，一个是图片的 url，一个是完成的 completedBlock。这个 block 会在图像操作完毕的时候执行。
1 typedef void(^SDExternalCompletionBlock)(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL);
1 /** 2 * Set the imageView `image` with an `url`, placeholder. 3 * 4 * The download is asynchronous and cached. 5 * 6 * @param url The url for the image. 7 * @param placeholder The image to be set initially, until the image request finishes. 8 * @param completedBlock A block called when operation has been completed. This block has no return value 9 * and takes the requested UIImage as first parameter. In case of error the image parameter 10 * is nil and the second parameter may contain an NSError. The third parameter is a Boolean 11 * indicating if the image was retrieved from the local cache or from the network. 12 * The fourth parameter is the original image url. 13 */ 14 - (void)sd_setImageWithURL:(nullable NSURL *)url 15 placeholderImage:(nullable UIImage *)placeholder 16 completed:(nullable SDExternalCompletionBlock)completedBlock;
添加一个占位图片。
1 /** 2 * Set the imageView `image` with an `url`, placeholder and custom options. 3 * 4 * The download is asynchronous and cached. 5 * 6 * @param url The url for the image. 7 * @param placeholder The image to be set initially, until the image request finishes. 8 * @param options The options to use when downloading the image. @see SDWebImageOptions for the possible values. 9 * @param completedBlock A block called when operation has been completed. This block has no return value 10 * and takes the requested UIImage as first parameter. In case of error the image parameter 11 * is nil and the second parameter may contain an NSError. The third parameter is a Boolean 12 * indicating if the image was retrieved from the local cache or from the network. 13 * The fourth parameter is the original image url. 14 */ 15 - (void)sd_setImageWithURL:(nullable NSURL *)url 16 placeholderImage:(nullable UIImage *)placeholder 17 options:(SDWebImageOptions)options 18 completed:(nullable SDExternalCompletionBlock)completedBlock;
再添加一个下载选项。
1 /** 2 * Set the imageView `image` with an `url`, placeholder and custom options. 3 * 4 * The download is asynchronous and cached. 5 * 6 * @param url The url for the image. 7 * @param placeholder The image to be set initially, until the image request finishes. 8 * @param options The options to use when downloading the image. @see SDWebImageOptions for the possible values. 9 * @param progressBlock A block called while image is downloading 10 * @note the progress block is executed on a background queue 11 * @param completedBlock A block called when operation has been completed. This block has no return value 12 * and takes the requested UIImage as first parameter. In case of error the image parameter 13 * is nil and the second parameter may contain an NSError. The third parameter is a Boolean 14 * indicating if the image was retrieved from the local cache or from the network. 15 * The fourth parameter is the original image url. 16 */ 17 - (void)sd_setImageWithURL:(nullable NSURL *)url 18 placeholderImage:(nullable UIImage *)placeholder 19 options:(SDWebImageOptions)options 20 progress:(nullable SDWebImageDownloaderProgressBlock)progressBlock 21 completed:(nullable SDExternalCompletionBlock)completedBlock;
再添加一个下载进度的 block。
这个 progressBlock 在后台队列中执行。
1 /** 2 * Set the imageView `image` with an `url` and optionally a placeholder image. 3 * 4 * The download is asynchronous and cached. 5 * 6 * @param url The url for the image. 7 * @param placeholder The image to be set initially, until the image request finishes. 8 * @param options The options to use when downloading the image. @see SDWebImageOptions for the possible values. 9 * @param progressBlock A block called while image is downloading 10 * @note the progress block is executed on a background queue 11 * @param completedBlock A block called when operation has been completed. This block has no return value 12 * and takes the requested UIImage as first parameter. In case of error the image parameter 13 * is nil and the second parameter may contain an NSError. The third parameter is a Boolean 14 * indicating if the image was retrieved from the local cache or from the network. 15 * The fourth parameter is the original image url. 16 */ 17 - (void)sd_setImageWithPreviousCachedImageWithURL:(nullable NSURL *)url 18 placeholderImage:(nullable UIImage *)placeholder 19 options:(SDWebImageOptions)options 20 progress:(nullable SDWebImageDownloaderProgressBlock)progressBlock 21 completed:(nullable SDExternalCompletionBlock)completedBlock;
获取缓存里面的图片。
Animation of multiple images
1 /** 2 * Download an array of images and starts them in an animation loop 3 * 4 * @param arrayOfURLs An array of NSURL 5 */ 6 - (void)sd_setAnimationImagesWithURLs:(nonnull NSArray<NSURL *> *)arrayOfURLs;
下载一组图像并在动画循环中启动它们。
1 - (void)sd_cancelCurrentAnimationImagesLoad;
取消当前的图片操作。
.m
1 - (void)sd_setImageWithURL:(nullable NSURL *)url {
2 [self sd_setImageWithURL:url placeholderImage:nil options:0 progress:nil completed:nil];
3 }
4
5 - (void)sd_setImageWithURL:(nullable NSURL *)url placeholderImage:(nullable UIImage *)placeholder {
6 [self sd_setImageWithURL:url placeholderImage:placeholder options:0 progress:nil completed:nil];
7 }
8
9 - (void)sd_setImageWithURL:(nullable NSURL *)url placeholderImage:(nullable UIImage *)placeholder options:(SDWebImageOptions)options {
10 [self sd_setImageWithURL:url placeholderImage:placeholder options:options progress:nil completed:nil];
11 }
12
13 - (void)sd_setImageWithURL:(nullable NSURL *)url completed:(nullable SDExternalCompletionBlock)completedBlock {
14 [self sd_setImageWithURL:url placeholderImage:nil options:0 progress:nil completed:completedBlock];
15 }
16
17 - (void)sd_setImageWithURL:(nullable NSURL *)url placeholderImage:(nullable UIImage *)placeholder completed:(nullable SDExternalCompletionBlock)completedBlock {
18 [self sd_setImageWithURL:url placeholderImage:placeholder options:0 progress:nil completed:completedBlock];
19 }
20
21 - (void)sd_setImageWithURL:(nullable NSURL *)url placeholderImage:(nullable UIImage *)placeholder options:(SDWebImageOptions)options completed:(nullable SDExternalCompletionBlock)completedBlock {
22 [self sd_setImageWithURL:url placeholderImage:placeholder options:options progress:nil completed:completedBlock];
23 }
占位图默认是 nil，下载选项默认是 0，即没有下载选项（SDWebImageOptions 是从 1 开始的），completed 默认是 nil。
1 - (void)sd_setImageWithURL:(nullable NSURL *)url
2 placeholderImage:(nullable UIImage *)placeholder
3 options:(SDWebImageOptions)options
4 progress:(nullable SDWebImageDownloaderProgressBlock)progressBlock
5 completed:(nullable SDExternalCompletionBlock)completedBlock {
6 [self sd_internalSetImageWithURL:url
7 placeholderImage:placeholder
8 options:options
9 operationKey:nil
10 setImageBlock:nil
11 progress:progressBlock
12 completed:completedBlock];
13 }
依然是调用 UIView 分类 WebCache 里面的方法。operationkey 和 setImageBlock 默认是 nil。
1 - (void)sd_setImageWithPreviousCachedImageWithURL:(nullable NSURL *)url
2 placeholderImage:(nullable UIImage *)placeholder
3 options:(SDWebImageOptions)options
4 progress:(nullable SDWebImageDownloaderProgressBlock)progressBlock
5 completed:(nullable SDExternalCompletionBlock)completedBlock {
6 NSString *key = [[SDWebImageManager sharedManager] cacheKeyForURL:url];
7 UIImage *lastPreviousCachedImage = [[SDImageCache sharedImageCache] imageFromCacheForKey:key];
8
9 [self sd_setImageWithURL:url placeholderImage:lastPreviousCachedImage ?: placeholder options:options progress:progressBlock completed:completedBlock];
10 }
从缓存里面读取图片，做占位图片。
1 - (void)sd_setAnimationImagesWithURLs:(nonnull NSArray<NSURL *> *)arrayOfURLs {
2 [self sd_cancelCurrentAnimationImagesLoad];
3 __weak __typeof(self)wself = self;
4
5 NSMutableArray<id<SDWebImageOperation>> *operationsArray = [[NSMutableArray alloc] init];
6
7 for (NSURL *logoImageURL in arrayOfURLs) {
8 id <SDWebImageOperation> operation = [SDWebImageManager.sharedManager loadImageWithURL:logoImageURL options:0 progress:nil completed:^(UIImage *image, NSData *data, NSError *error, SDImageCacheType cacheType, BOOL finished, NSURL *imageURL) {
9 if (!wself) return;
10 dispatch_main_async_safe(^{
11 __strong UIImageView *sself = wself;
12 [sself stopAnimating];
13 if (sself && image) {
14 NSMutableArray<UIImage *> *currentImages = [[sself animationImages] mutableCopy];
15 if (!currentImages) {
16 currentImages = [[NSMutableArray alloc] init];
17 }
18 [currentImages addObject:image];
19
20 sself.animationImages = currentImages;
21 [sself setNeedsLayout];
22 }
23 [sself startAnimating];
24 });
25 }];
26 [operationsArray addObject:operation];
27 }
28
29 [self sd_setImageLoadOperation:[operationsArray copy] forKey:@"UIImageViewAnimationImages"];
30 }
下载一组图片添加到 UIImageView 的 animationImages 里面。
1 - (void)sd_cancelCurrentAnimationImagesLoad {
2 [self sd_cancelImageLoadOperationWithKey:@"UIImageViewAnimationImages"];
3 }
调用 UIView 的分类 WebCacheOperation 里面的方法。取消所有的操作。
END