iOS 清理缓存功能的实现第二种方法

/**
 *  清理缓存第二种方法
 *
 *  @param sender <#sender description#>
 */
- (void)clearCache:(id)sender
{
    //彻底清除缓存第一种方法
    UIButton * button = sender;
    [button setTitle:@"清理完毕" forState:UIControlStateNormal];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
    NSString *path = [paths lastObject];

    NSString *str = [NSString stringWithFormat:@"缓存已清除%.1fM", [self folderSizeAtPath:path]];
    NSLog(@"%@",str);
    NSArray *files = [[NSFileManager defaultManager] subpathsAtPath:path];
    for (NSString *p in files) {
        NSError *error;
        NSString *Path = [path stringByAppendingPathComponent:p];
        if ([[NSFileManager defaultManager] fileExistsAtPath:Path]) {
            [[NSFileManager defaultManager] removeItemAtPath:Path error:&error];
        }
    }
}
/**
 *  计算单个文件大小
 */
- (long long) fileSizeAtPath:(NSString*) filePath{
    NSFileManager* manager = [NSFileManager defaultManager];
    if ([manager fileExistsAtPath:filePath]){
        return [[manager attributesOfItemAtPath:filePath error:nil] fileSize];
    }
    return 0;
}

/**
 *  计算目录大小  遍历文件夹获得文件夹大小，返回多少M
 */
- (float ) folderSizeAtPath:(NSString*) folderPath{
    NSFileManager* manager = [NSFileManager defaultManager];
    if (![manager fileExistsAtPath:folderPath]) return 0;
    NSEnumerator *childFilesEnumerator = [[manager subpathsAtPath:folderPath] objectEnumerator];
    NSString* fileName;
    long long folderSize = 0;
    while ((fileName = [childFilesEnumerator nextObject]) != nil){
        NSString* fileAbsolutePath = [folderPath stringByAppendingPathComponent:fileName];
        folderSize += [self fileSizeAtPath:fileAbsolutePath];
    }
    return folderSize/(1024.0*1024.0);
}