SDWebImage使用简介

SDWebImage是一个缓存图片的第三方，下面介绍几种简单使用
GitHub下载地址：https://github.com/rs/SDWebImage

    NSLog(@"%@",[NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) lastObject]);
//打印沙盒路径，缓存图片保存在沙盒路径中。

#pragma mark 下载图片
- (IBAction)tapDownLoadPic:(UIButton *)sender {
    NSString *urlStr1 = @"http://img02.tooopen.com/images/20160327/tooopen_sy_157439572224.jpg";
    NSString *urlStr2 = @"http://img02.tooopen.com/images/20160320/tooopen_sy_156512393637.jpg";
    NSURL *url1 = [NSURL URLWithString:urlStr1];
    NSURL *url2 = [NSURL URLWithString:urlStr2];
    //直接下载缓存图片
    [self.image1 sd_setImageWithURL:url1];

    //带有占位图片的，缓存结束后自动替换
    [self.image2 sd_setImageWithURL:url2 placeholderImage:[UIImage imageNamed:@"111"]];

    //block中可以查看图片来源
     [self.image2 sd_setImageWithURL:url2 placeholderImage:[UIImage imageNamed:@"111"] completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, NSURL *imageURL) {
         NSLog(@"url == %@",imageURL);
         NSLog(@"图片来自：%ld",cacheType);
//cacheType 0- 网络 1-磁盘 2- 内存
     }];

    //可设置选项，SDWebImageOptions可以设置自动重试、仅保存内存中等
    [self.image2 sd_setImageWithURL:url2 placeholderImage:[UIImage imageNamed:@"111"] options:SDWebImageRetryFailed];
    
    //监测下载进度
    [self.image2 sd_setImageWithURL:url2 placeholderImage:[UIImage imageNamed:@"111"] options:SDWebImageRetryFailed progress:^(NSInteger receivedSize, NSInteger expectedSize) {
        NSLog(@"进度：%lf",(double)(receivedSize/expectedSize));
    } completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, NSURL *imageURL) {
        NSLog(@"图片来自：%ld",cacheType);
    }];
    
    //观察下载进度，不显示图片。
    [[SDWebImageManager sharedManager]downloadImageWithURL:url2 options:SDWebImageRetryFailed progress:^(NSInteger receivedSize, NSInteger expectedSize) {
        NSLog(@"进度：%lf",(double)(receivedSize/expectedSize));
    } completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, BOOL finished, NSURL *imageURL) {
        NSLog(@"图片来自：%ld",cacheType);
    }];
    
    //取消下载所有
    [[SDWebImageManager sharedManager] cancelAll];
    
}
#pragma mark 清除内存

- (IBAction)clearNeicun:(UIButton *)sender {
    [[SDImageCache sharedImageCache] clearMemory];
}

#pragma mark 清除过期图片（默认7天过期）

- (IBAction)clearDateOut:(UIButton *)sender {
    [[SDImageCache sharedImageCache] cleanDisk];
}

#pragma mark 清除磁盘

- (IBAction)clearDisk:(UIButton *)sender {
    [[SDImageCache sharedImageCache] clearDisk];
}