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];  

#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];
}