【iOS】Class对构造简洁代码很有帮助

（这到底取的是什么标题啊）
首先先看这段代码（有删减）

@property (nonatomic, copy)NSMutableArray <NSMutableArray *>*datas;
- (void)viewDidLoad {
     NSMutableArray *section0 = @[
                   @{@"title" : @"我的借阅",
                     @"leftIcon" : @"my_borrow",
                     @"vc" : @"ManageBooksViewController"}.mutableCopy,
                   @{@"title" : @"我的书籍",
                     @"leftIcon" : @"my_book",
                     @"vc" : @"MyFileViewController"}.mutableCopy,
                   ].mutableCopy
                   ...
    self.datas = @[section0,section1,section2, section3].mutableCopy;
}
#pragma mark 选择事件
- (void) tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    NSInteger row = indexPath.row;
    NSInteger section = indexPath.section;
    NSString *vcStr = self.datas[section][row][@"vc"];

    if ([vcStr isEqualToString:@"MineIntroductionViewController"]) {
        ActivityWebViewController *vc = [[ActivityWebViewController alloc]initWithContentUrl:@"http://librarymanager.30days-tech.com/h5/introduce.html"
                                                                                       title:@"使用说明"
                                                                                  presenting:NO];
        vc.hidesBottomBarWhenPushed = YES;
        [self.navigationController pushViewController:vc
                                              animated:YES];
    }
    if ([vcStr isEqualToString:@"MyFileViewController"]) {
        ManageBooksViewController *vc = [[ManageBooksViewController alloc]init];
        vc.hidesBottomBarWhenPushed = YES;
        [self.navigationController pushViewController:vc
                                             animated:YES];

    } else if ([vcStr isEqualToString:@"MyBooksViewController"]) {
        MyFileViewController *vc = [[MyFileViewController alloc]init];
        vc.hidesBottomBarWhenPushed = YES;
        [self.navigationController pushViewController:vc
                                             animated:YES];
    } else if ([vcStr isEqualToString:@"MyMoreSettingViewController"]) {
        MyMoreSettingViewController *vc = [[MyMoreSettingViewController alloc]init];
        vc.hidesBottomBarWhenPushed = YES;
        [self.navigationController pushViewController:vc
                                             animated:YES];
    }
    .......
}

着看之下貌似没什么问题，语法也说得过去，而且总比用indexPath来判断进入哪个控制器要简单得多，后期修改也不存在太大的问题，但随着需求的增加我们会发现每多出一个控制器，push控制器代码又会多出一段：

XXX *vc = [[XXX alloc]init];
        vc.hidesBottomBarWhenPushed = YES;
        [self.navigationController pushViewController:vc
                                             animated:YES];

so，利用Class就可以瞬间把代码缩减好了。

#pragma mark 选择事件
- (void) tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    NSInteger row = indexPath.row;
    NSInteger section = indexPath.section;
    NSString *vcStr = self.datas[section][row][@"vc"];
    Class vcClass = NSClassFromString(vcStr) ;
    if (vcClass) {
        UIViewController *vc = [[vcClass alloc]init];
        vc.hidesBottomBarWhenPushed = YES;
        [self.navigationController pushViewController:vc
                                             animated:YES];
        return ;
    }
}

看，很方便吧！