顶部滚动菜单

属性：

//菜单内容
@property (nonatomic, strong) NSArray *titles;
//默认颜色 default:BlackColor
@property (nonatomic, strong) UIColor *nomalColor;
//选中颜色 default:RedColor
@property (nonatomic, strong) UIColor *selectedColor;
//指示器颜色 default:BlackColor
@property (nonatomic, strong) UIColor *IndicatorColor;
//高度 default:40
@property (nonatomic, assign) CGFloat menuHeight;
//delegate
@property (nonatomic, weak) id<LBTopScrollMenuDelegate> delegate_topMenu;

代理方法：

//index:选中的item编号
- (void)topScrollMenu:(LBTopScrollMenu *)scrollMenu didSelectedItemInIndex:(NSUInteger)index;

公共方法:

//init titles:菜单内容
- (instancetype)initWithFrame:(CGRect)frame titles:(NSArray *)titles;
//更新指示器 index:当前选中的item的编号
- (void)updateIndicatorWithSelectedItemIndex:(NSUInteger)index;

使用方法：

//懒加载
- (LBTopScrollMenu *)topMenu
{
    if (!_topMenu) {
        //初始化有三种方法，init、initWithFrame、initWithFrame: titles:
        _topMenu = [[LBTopScrollMenu alloc] init];
        _topMenu.backgroundColor = [UIColor greenColor];
        _topMenu.menuHeight = 40;
        _topMenu.titles = self.titles;
        _topMenu.delegate_topMenu = self;
        _topMenu.nomalColor = [UIColor yellowColor];
        _topMenu.selectedColor = [UIColor redColor];
        _topMenu.lineColor = [UIColor blueColor];
    }
    return _topMenu;
}
//<LBTopScrollMenuDelegate>
- (void)topScrollMenu:(LBTopScrollMenu *)scrollMenu didSelectedItemInIndex:(NSUInteger)index
{
    //偏移
    [self.scrollView setContentOffset:CGPointMake(index * CGRectGetWidth(self.view.frame), 0) animated:YES];
}
//<UIScrollViewDelegate>
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    NSUInteger index = scrollView.contentOffset.x / CGRectGetWidth(self.view.frame);
    //更新指示器
    [self.topMenu updateIndicatorWithSelectedItemIndex:index];
}