该文章阅读的SDWebImage的版本为4.3.3。

这个分类提供了为UIButton设置网络图像的快捷方法。

1.公共方法

1.1.设置image的方法

/**获取当前图像链接地址*/
- (nullable NSURL *)sd_currentImageURL;
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/**获取指定状态图像链接地址*/
- (nullable NSURL *)sd_imageURLForState:(UIControlState)state;
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/**设置指定状态的图像链接地址*/
- (void)sd_setImageWithURL:(nullable NSURL *)urlforState:(UIControlState)state NS_REFINED_FOR_SWIFT;
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/**设置指定状态的图像链接地址和占位图*/
- (void)sd_setImageWithURL:(nullable NSURL *)urlforState:(UIControlState)stateplaceholderImage:(nullable UIImage *)placeholder NS_REFINED_FOR_SWIFT;
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/**设置指定状态的图像链接地址和占位图以及可选项*/
- (void)sd_setImageWithURL:(nullable NSURL *)urlforState:(UIControlState)stateplaceholderImage:(nullable UIImage *)placeholderoptions:(SDWebImageOptions)options NS_REFINED_FOR_SWIFT;
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/**设置指定状态的图像链接地址和完成回调*/
- (void)sd_setImageWithURL:(nullable NSURL *)urlforState:(UIControlState)statecompleted:(nullable SDExternalCompletionBlock)completedBlock;
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/**设置指定状态的图像链接地址和占位图以及完成回调*/
- (void)sd_setImageWithURL:(nullable NSURL *)urlforState:(UIControlState)stateplaceholderImage:(nullable UIImage *)placeholdercompleted:(nullable SDExternalCompletionBlock)completedBlock NS_REFINED_FOR_SWIFT;
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/**设置指定状态的图像链接地址、占位图、可选项以及完成回调*/
- (void)sd_setImageWithURL:(nullable NSURL *)urlforState:(UIControlState)stateplaceholderImage:(nullable UIImage *)placeholderoptions:(SDWebImageOptions)optionscompleted:(nullable SDExternalCompletionBlock)completedBlock;
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1.2.设置background image的方法

/**获取当前背景图像链接地址*/
- (nullable NSURL *)sd_currentBackgroundImageURL;/**获取指定状态背景图像链接地址*/
- (nullable NSURL *)sd_backgroundImageURLForState:(UIControlState)state;/**设置指定状态的背景图像链接地址*/
- (void)sd_setBackgroundImageWithURL:(nullable NSURL *)urlforState:(UIControlState)state NS_REFINED_FOR_SWIFT;
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/**设置指定状态的背景图像链接地址和占位图*/
- (void)sd_setBackgroundImageWithURL:(nullable NSURL *)urlforState:(UIControlState)stateplaceholderImage:(nullable UIImage *)placeholder NS_REFINED_FOR_SWIFT;
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/**设置指定状态的背景图像链接地址和占位图以及可选项*/
- (void)sd_setBackgroundImageWithURL:(nullable NSURL *)urlforState:(UIControlState)stateplaceholderImage:(nullable UIImage *)placeholderoptions:(SDWebImageOptions)options NS_REFINED_FOR_SWIFT;
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/**设置指定状态的背景图像链接地址和占位图以及完成回调*/
- (void)sd_setBackgroundImageWithURL:(nullable NSURL *)urlforState:(UIControlState)statecompleted:(nullable SDExternalCompletionBlock)completedBlock;
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/**设置指定状态的背景图像链接地址和占位图以及完成回调*/
- (void)sd_setBackgroundImageWithURL:(nullable NSURL *)urlforState:(UIControlState)stateplaceholderImage:(nullable UIImage *)placeholdercompleted:(nullable SDExternalCompletionBlock)completedBlock NS_REFINED_FOR_SWIFT;
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/**设置指定状态的背景图像链接地址、占位图、可选项以及完成回调*/
- (void)sd_setBackgroundImageWithURL:(nullable NSURL *)urlforState:(UIControlState)stateplaceholderImage:(nullable UIImage *)placeholderoptions:(SDWebImageOptions)optionscompleted:(nullable SDExternalCompletionBlock)completedBlock;复制代码

1.3.取消网络图像加载的方法

/**取消指定状态当前图像的网络加载*/
- (void)sd_cancelImageLoadForState:(UIControlState)state;
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/**取消指定状态当前背景图像的网络加载*/
- (void)sd_cancelBackgroundImageLoadForState:(UIControlState)state;
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2.私有静态函数

/**获取指定状态的图像链接键*/
static inline NSString * imageURLKeyForState(UIControlState state) {return [NSString stringWithFormat:@"image_%lu", (unsigned long)state];
}
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/**获取指定状态的背景图像链接键*/
static inline NSString * backgroundImageURLKeyForState(UIControlState state) {return [NSString stringWithFormat:@"backgroundImage_%lu", (unsigned long)state];
}
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/**获取指定状态的图像选项键*/
static inline NSString * imageOperationKeyForState(UIControlState state) {return [NSString stringWithFormat:@"UIButtonImageOperation%lu", (unsigned long)state];
}
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/**获取指定状态的背景图像选项键*/
static inline NSString * backgroundImageOperationKeyForState(UIControlState state) {return [NSString stringWithFormat:@"UIButtonBackgroundImageOperation%lu", (unsigned long)state];
}
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3.私有方法

/**获取保存图像链接的字典对象*/
- (SDStateImageURLDictionary *)sd_imageURLStorage {SDStateImageURLDictionary *storage = objc_getAssociatedObject(self, &imageURLStorageKey);if (!storage) {storage = [NSMutableDictionary dictionary];objc_setAssociatedObject(self, &imageURLStorageKey, storage, OBJC_ASSOCIATION_RETAIN_NONATOMIC);}return storage;
}
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4.实现

4.1.设置image的方法实现

- (nullable NSURL *)sd_currentImageURL {// 获取当前状态的图像地址NSURL *url = self.sd_imageURLStorage[imageURLKeyForState(self.state)];// 如果没有就获取普通状态的图像地址if (!url) {url = self.sd_imageURLStorage[imageURLKeyForState(UIControlStateNormal)];}return url;
}- (nullable NSURL *)sd_imageURLForState:(UIControlState)state {// 获取指定状态的图像地址return self.sd_imageURLStorage[imageURLKeyForState(state)];
}- (void)sd_setImageWithURL:(nullable NSURL *)url forState:(UIControlState)state {// 调用全能方法[self sd_setImageWithURL:url forState:state placeholderImage:nil options:0 completed:nil];
}- (void)sd_setImageWithURL:(nullable NSURL *)url forState:(UIControlState)state placeholderImage:(nullable UIImage *)placeholder {// 调用全能方法[self sd_setImageWithURL:url forState:state placeholderImage:placeholder options:0 completed:nil];
}- (void)sd_setImageWithURL:(nullable NSURL *)url forState:(UIControlState)state placeholderImage:(nullable UIImage *)placeholder options:(SDWebImageOptions)options {[self sd_setImageWithURL:url forState:state placeholderImage:placeholder options:options completed:nil];
}- (void)sd_setImageWithURL:(nullable NSURL *)url forState:(UIControlState)state completed:(nullable SDExternalCompletionBlock)completedBlock {// 调用全能方法[self sd_setImageWithURL:url forState:state placeholderImage:nil options:0 completed:completedBlock];
}- (void)sd_setImageWithURL:(nullable NSURL *)url forState:(UIControlState)state placeholderImage:(nullable UIImage *)placeholder completed:(nullable SDExternalCompletionBlock)completedBlock {// 调用全能方法[self sd_setImageWithURL:url forState:state placeholderImage:placeholder options:0 completed:completedBlock];
}- (void)sd_setImageWithURL:(nullable NSURL *)urlforState:(UIControlState)stateplaceholderImage:(nullable UIImage *)placeholderoptions:(SDWebImageOptions)optionscompleted:(nullable SDExternalCompletionBlock)completedBlock {if (!url) {// 不传链接就移除掉指定状态对应的值[self.sd_imageURLStorage removeObjectForKey:imageURLKeyForState(state)];} else {// 根据指定状态保存链接self.sd_imageURLStorage[imageURLKeyForState(state)] = url;}// 调用UIView+WebCache分类方法加载图像__weak typeof(self)weakSelf = self;[self sd_internalSetImageWithURL:urlplaceholderImage:placeholderoptions:optionsoperationKey:imageOperationKeyForState(state)setImageBlock:^(UIImage *image, NSData *imageData) {[weakSelf setImage:image forState:state];}progress:nilcompleted:completedBlock];
}
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4.2.设置background image的方法实现

- (nullable NSURL *)sd_currentBackgroundImageURL {// 获取当前状态的背景图像地址NSURL *url = self.sd_imageURLStorage[backgroundImageURLKeyForState(self.state)];// 如果没有就获取普通状态的背景图像地址if (!url) {url = self.sd_imageURLStorage[backgroundImageURLKeyForState(UIControlStateNormal)];}return url;
}- (nullable NSURL *)sd_backgroundImageURLForState:(UIControlState)state {// 获取指定状态的背景图像地址return self.sd_imageURLStorage[backgroundImageURLKeyForState(state)];
}- (void)sd_setBackgroundImageWithURL:(nullable NSURL *)url forState:(UIControlState)state {// 调用全能方法[self sd_setBackgroundImageWithURL:url forState:state placeholderImage:nil options:0 completed:nil];
}- (void)sd_setBackgroundImageWithURL:(nullable NSURL *)url forState:(UIControlState)state placeholderImage:(nullable UIImage *)placeholder {// 调用全能方法[self sd_setBackgroundImageWithURL:url forState:state placeholderImage:placeholder options:0 completed:nil];
}- (void)sd_setBackgroundImageWithURL:(nullable NSURL *)url forState:(UIControlState)state placeholderImage:(nullable UIImage *)placeholder options:(SDWebImageOptions)options {// 调用全能方法[self sd_setBackgroundImageWithURL:url forState:state placeholderImage:placeholder options:options completed:nil];
}- (void)sd_setBackgroundImageWithURL:(nullable NSURL *)url forState:(UIControlState)state completed:(nullable SDExternalCompletionBlock)completedBlock {// 调用全能方法[self sd_setBackgroundImageWithURL:url forState:state placeholderImage:nil options:0 completed:completedBlock];
}- (void)sd_setBackgroundImageWithURL:(nullable NSURL *)url forState:(UIControlState)state placeholderImage:(nullable UIImage *)placeholder completed:(nullable SDExternalCompletionBlock)completedBlock {// 调用全能方法[self sd_setBackgroundImageWithURL:url forState:state placeholderImage:placeholder options:0 completed:completedBlock];
}- (void)sd_setBackgroundImageWithURL:(nullable NSURL *)urlforState:(UIControlState)stateplaceholderImage:(nullable UIImage *)placeholderoptions:(SDWebImageOptions)optionscompleted:(nullable SDExternalCompletionBlock)completedBlock {if (!url) {// 不传链接就移除掉指定状态对应的值[self.sd_imageURLStorage removeObjectForKey:backgroundImageURLKeyForState(state)];} else {// 根据指定状态保存链接self.sd_imageURLStorage[backgroundImageURLKeyForState(state)] = url;}// 调用UIView+WebCache分类方法加载背景图像__weak typeof(self)weakSelf = self;[self sd_internalSetImageWithURL:urlplaceholderImage:placeholderoptions:optionsoperationKey:backgroundImageOperationKeyForState(state)setImageBlock:^(UIImage *image, NSData *imageData) {[weakSelf setBackgroundImage:image forState:state];}progress:nilcompleted:completedBlock];
}
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4.3.取消网络图像加载的方法实现

- (void)sd_cancelImageLoadForState:(UIControlState)state {// 取消指定key的图像加载操作[self sd_cancelImageLoadOperationWithKey:imageOperationKeyForState(state)];
}- (void)sd_cancelBackgroundImageLoadForState:(UIControlState)state {// 取消指定key的背景图像加载操作[self sd_cancelImageLoadOperationWithKey:backgroundImageOperationKeyForState(state)];
}
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源码阅读系列：SDWebImage

源码阅读：SDWebImage（一）——从使用入手

源码阅读：SDWebImage（二）——SDWebImageCompat

源码阅读：SDWebImage（三）——NSData+ImageContentType

源码阅读：SDWebImage（四）——SDWebImageCoder

源码阅读：SDWebImage（五）——SDWebImageFrame

源码阅读：SDWebImage（六）——SDWebImageCoderHelper

源码阅读：SDWebImage（七）——SDWebImageImageIOCoder

源码阅读：SDWebImage（八）——SDWebImageGIFCoder

源码阅读：SDWebImage（九）——SDWebImageCodersManager

源码阅读：SDWebImage（十）——SDImageCacheConfig

源码阅读：SDWebImage（十一）——SDImageCache

源码阅读：SDWebImage（十二）——SDWebImageDownloaderOperation

源码阅读：SDWebImage（十三）——SDWebImageDownloader

源码阅读：SDWebImage（十四）——SDWebImageManager

源码阅读：SDWebImage（十五）——SDWebImagePrefetcher

源码阅读：SDWebImage（十六）——SDWebImageTransition

源码阅读：SDWebImage（十七）——UIView+WebCacheOperation

源码阅读：SDWebImage（十八）——UIView+WebCache

源码阅读：SDWebImage（十九）——UIImage+ForceDecode/UIImage+GIF/UIImage+MultiFormat

源码阅读：SDWebImage（二十）——UIButton+WebCache

源码阅读：SDWebImage（二十一）——UIImageView+WebCache/UIImageView+HighlightedWebCache