1.创建_pageControl对象
UIPageControl 继承 UIControl

CGFloat PX = 0;
CGFloat PH = 20;
CGFloat PY = _scrollView.frame.size.height - PH;
CGFloat PW = _scrollView.frame.size.width;

UIPageControl * pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(PX, PY, PW, PH)];

2.显示在界面上

[self.view addSubview:_pageControl];

3.设置背景颜色

    _pageControl.backgroundColor = [UIColor blackColor];
    _pageControl.alpha = 0.5f;

核心设置

4.设置分页数据(默认0)

    _pageControl.numberOfPages = 6;

5.设置当前分页（默认0）

_pageControl.currentPage = 0;

6.没有选中的分页的填充颜色

 _pageControl.pageIndicatorTintColor = [UIColor redColor];

7.选中的分页的填充颜色

 _pageControl.currentPageIndicatorTintColor = [UIColor yellowColor];

8.关闭用户交互

 _pageControl.userInteractionEnabled = NO;