1.获取路径：

// 获取Caches目录路径
- (NSString *)getCachesPath{ 
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask,YES);
    NSString *cachesDir = [paths lastObject];
    return cachesDir;
}

2.计算目录大小

- (CGFloat)folderSizeAtPath:(NSString *)path{
    NSFileManager *manager = [NSFileManager defaultManager];
    CGFloat size = 0;
    if ([manager fileExistsAtPath:path]) {
        // 目录下的文件计算大小
        NSArray *childrenFile = [manager subpathsAtPath:path];
        for (NSString *fileName in childrenFile) {
            NSString *absolutePath = [path stringByAppendingPathComponent:fileName];
            size += [manager attributesOfItemAtPath:absolutePath error:nil].fileSize;
        }
        //SDWebImage的缓存计算
        size += [[SDImageCache sharedImageCache] getSize]/1024.0/1024.0;
        // 将大小转化为M,size单位b,转，KB,MB除以两次1024
        return size / 1024.0 / 1024.0;
    }
    return 0;
}

3.根据路径删除文件

- (void)cleanCaches:(NSString *)path{
    NSFileManager *fileManager = [NSFileManager defaultManager];
    if ([fileManager fileExistsAtPath:path]) {
        NSArray *childrenFiles = [fileManager subpathsAtPath:path];
        for (NSString *fileName in childrenFiles) {
            // 拼接路径
            NSString *absolutePath = [path stringByAppendingPathComponent:fileName];
            // 将文件删除
            [fileManager removeItemAtPath:absolutePath error:nil];
        }
    }
    //SDWebImage的清除功能
    [[SDImageCache sharedImageCache] clearDisk];
    [[SDImageCache sharedImageCache] clearMemory];
}

4.清除缓存按钮的点击事件

- (void)cleanButtonAction:(UIButton *)btn{
    CGFloat size = [self folderSizeAtPath:NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).lastObject] + [self folderSizeAtPath:NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES).lastObject] + [self folderSizeAtPath:NSTemporaryDirectory()];
    
    NSString *message = size > 1 ? [NSString stringWithFormat:@"缓存%.2fM", size] : [NSString stringWithFormat:@"缓存%.2fK", size * 1024.0];
    
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"删除缓存" message:message preferredStyle:UIAlertControllerStyleAlert];
    
    UIAlertAction *action = [UIAlertAction actionWithTitle:@"确定" style:(UIAlertActionStyleDefault) handler:^(UIAlertAction *action) {
        
        [self cleanCaches:[self getCachesPath]];
    }];

    UIAlertAction *cancel = [UIAlertAction actionWithTitle:@"取消" style:(UIAlertActionStyleCancel) handler:nil];
    [alertController addAction:action];
    [alertController addAction:cancel];
    [self presentViewController:alertController animated:YES completion:nil];
}