SDWebImage---iOS笔记摘录

目录

1. 简介

    异步图像下载
    支持GIF动画
    保证相同的url不会下载多次
    保证主线程永远不会被阻塞

2. 使用

  pod 'SDWebImage'

2.1 UIImageView

  #import "UIImageView+WebCache.h"

    [imgV sd_setImageWithURL:[NSURL URLWithString:@""]];
    [imgV sd_setImageWithURL:[NSURL URLWithString:@""] completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
    }];
    [imgV sd_setImageWithURL:[NSURL URLWithString:@""] placeholderImage:[UIImage imageNamed:@""] options:SDWebImageLowPriority];
    [imgV sd_setImageWithURL:[NSURL URLWithString:@""] placeholderImage:[UIImage imageNamed:@""] completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
    }];
    [imgV sd_setImageWithURL:[NSURL URLWithString:@""] placeholderImage:[UIImage imageNamed:@""] options:SDWebImageLowPriority completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
    }];
    // 以上方法都会调用如下方法（这是通常的做法）
    [imgV sd_setImageWithURL:[NSURL URLWithString:@""] placeholderImage:[UIImage imageNamed:@""] options:SDWebImageLowPriority progress:^(NSInteger receivedSize, NSInteger expectedSize, NSURL * _Nullable targetURL) {
    } completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
    }];
    /*
options:
     SDWebImageRetryFailed（失败后重试）
     SDWebImageLowPriority（交互时就下载，影响流畅）
     SDWebImageCacheMemoryOnly（只进行内存缓存）
     SDWebImageProgressiveDownload（渐进式下载）
     SDWebImageRefreshCached（刷新缓存,若地址改变图片不变则使用）
     SDWebImageContinueInBackground（后台下载）
     SDWebImageHandleCookies
     SDWebImageAllowInvalidSSLCertificates（允许使用无效SSL）
     SDWebImageHighPriority（优先下载）
     SDWebImageDelayPlaceholder
     SDWebImageTransformAnimatedImage
     */


    // 动画
    [imgV sd_setAnimationImagesWithURLs:@[[NSURL URLWithString:@""]]];
    // 取消当前动画
    [imgV sd_cancelCurrentAnimationImagesLoad];

图片加载流程

2.2 UIButton

  #import "UIButton+WebCache.h"


    [completeButton sd_setImageWithURL:[NSURL URLWithString:@""] forState:UIControlStateNormal];
    [completeButton sd_setImageWithURL:[NSURL URLWithString:@""] forState:UIControlStateNormal completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
    }];
    [completeButton sd_setImageWithURL:[NSURL URLWithString:@""] forState:UIControlStateNormal placeholderImage:[UIImage imageNamed:@""]];
    [completeButton sd_setImageWithURL:[NSURL URLWithString:@""] forState:UIControlStateNormal placeholderImage:[UIImage imageNamed:@""] options:SDWebImageRetryFailed];
    [completeButton sd_setImageWithURL:[NSURL URLWithString:@""] forState:UIControlStateNormal placeholderImage:[UIImage imageNamed:@""] completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
    }];
    // 以上方法都会调用如下方法（常见封装方式）
    [completeButton sd_setImageWithURL:[NSURL URLWithString:@""] forState:UIControlStateNormal placeholderImage:[UIImage imageNamed:@""] options:SDWebImageRetryFailed completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
    }];
    
    
    [completeButton sd_setBackgroundImageWithURL:[NSURL URLWithString:@""] forState:UIControlStateNormal];
    [completeButton sd_setBackgroundImageWithURL:[NSURL URLWithString:@""] forState:UIControlStateNormal completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
    }];
    [completeButton sd_setBackgroundImageWithURL:[NSURL URLWithString:@""] forState:UIControlStateNormal placeholderImage:[UIImage imageNamed:@""]];
    [completeButton sd_setBackgroundImageWithURL:[NSURL URLWithString:@""] forState:UIControlStateNormal placeholderImage:[UIImage imageNamed:@""] options:SDWebImageRetryFailed];
    [completeButton sd_setBackgroundImageWithURL:[NSURL URLWithString:@""] forState:UIControlStateNormal placeholderImage:[UIImage imageNamed:@""] completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
    }];
    // 以上方法都会调用如下方法（常见封装方式）
    [completeButton sd_setBackgroundImageWithURL:[NSURL URLWithString:@""] forState:UIControlStateNormal placeholderImage:[UIImage imageNamed:@""] options:SDWebImageRetryFailed completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
    }];

2.3 异步下载

#import "SDWebImageDownloader.h"


    // 下载图片
    SDWebImageDownLoader *downLoader=[SDWebImageDownloader sharedDownloader]downloadImageWithURL:[NSURL URLWithString:@""] options:SDWebImageDownloaderLowPriority progress:^(NSInteger receivedSize, NSInteger expectedSize, NSURL * _Nullable targetURL) {
    } completed:^(UIImage * _Nullable image, NSData * _Nullable data, NSError * _Nullable error, BOOL finished) {
    };
    /*
     options:
     
    SDWebImageDownloaderLowPriority             低优先级
    SDWebImageDownloaderProgressiveDownload     下载过程中逐步显示
    SDWebImageDownloaderUseNSURLCache           使用NSURLCache
    SDWebImageDownloaderIgnoreCachedResponse    组合SDWebImageDownloaderUseNSURLCache使用，当图片从缓存中获取时，completed中的image是nil
    SDWebImageDownloaderContinueInBackground    支持后台下载
    SDWebImageDownloaderHandleCookies           使用Cookies
    SDWebImageDownloaderAllowInvalidSSLCertificates     支持不安全的SSL连接（用于测试）
    SDWebImageDownloaderHighPriority            高优先级
    SDWebImageDownloaderScaleDownLargeImages    缩放大图片
     */

2.4 缓存

#import "SDImageCache.h"

    //
    SDImageCache *imgCache=[SDImageCache sharedImageCache];
    
    // 缓存
    // 缓存图片到沙盒
    [imgCache storeImageDataToDisk:[NSData data] forKey:@""];
    // 缓存图片到沙盒和内存
    [imgCache storeImage:[UIImage imageNamed:@""] forKey:@"" completion:^{
    }];
    // 缓存图片到内存,是否沙盒
    [imgCache storeImage:[UIImage imageNamed:@""] forKey:@"" toDisk:true completion:^{
    }];
    // 缓存图片到内存,是否沙盒
    [imgCache storeImage:[UIImage imageNamed:@""] imageData:nil forKey:@"" toDisk:true completion:^{
    }];
    
    // 获取
    // 获取缓存图片（先从内存再从沙盒）
    UIImage *img=[imgCache imageFromCacheForKey:@"key"];
    // 获取缓存图片（从内存）
    UIImage *img2=[imgCache imageFromMemoryCacheForKey:@"key"];
    // 获取缓存图片（从沙盒）
    UIImage *img3=[imgCache imageFromDiskCacheForKey:@"key"];