SDWebImage -- 判断缓存图片的大小（所占字节数）、手動清除緩存的方法

1.找到SDImageCache类

2.添加如下方法：

- (float)checkTmpSize
{
    float totalSize = 0;
    NSDirectoryEnumerator *fileEnumerator = [[NSFileManager defaultManager] enumeratorAtPath:diskCachePath];
    for (NSString *fileName in fileEnumerator)
    {
        NSString *filePath = [diskCachePath stringByAppendingPathComponent:fileName];

        NSDictionary *attrs = [[NSFileManager defaultManager] attributesOfItemAtPath:filePath error:nil];

        unsigned long long length = [attrs fileSize];

        totalSize += length / 1024.0 / 1024.0;
    }
//    NSLog(@"tmp size is %.2f",totalSize);

    return totalSize;
}

新版的SDImageCache类，已增加此方法

 [[SDImageCache sharedImageCache] getSize];

3.在设置里这样使用

 #pragma 清理缓存图片

 - (void)clearTmpPics
 {
     [[SDImageCache sharedImageCache] clearDisk];

 //    [[SDImageCache sharedImageCache] clearMemory];//可有可无

     DLog(@"clear disk");

     float tmpSize = [[SDImageCache sharedImageCache] checkTmpSize];

     NSString *clearCacheName = tmpSize >= 1 ? [NSString stringWithFormat:@"清理缓存(%.2fM)",tmpSize] : [NSString stringWithFormat:@"清理缓存(%.2fK)",tmpSize * 1024];

     [configDataArray replaceObjectAtIndex:2 withObject:clearCacheName];

     [configTableView reloadData];
 }