IOS 分页（pagingEnabled）

   
self.scrollView.pagingEnabled = YES;

- (void)nextImage
{
    // 1.增加pageControl的页码
    int page = 0;
    if (self.pageControl.currentPage == MJImageCount - 1) {
        page = 0;
    } else {
        page = self.pageControl.currentPage + 1;
    }
    
    // 2.计算scrollView滚动的位置
    CGFloat offsetX = page * self.scrollView.frame.size.width;
    CGPoint offset = CGPointMake(offsetX, 0);
    [self.scrollView setContentOffset:offset animated:YES];
}


#pragma mark - 代理方法
/**
 *  当scrollView正在滚动就会调用
 */
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    // 根据scrollView的滚动位置决定pageControl显示第几页
    CGFloat scrollW = scrollView.frame.size.width;
    int page = (scrollView.contentOffset.x + scrollW * 0.5) / scrollW;
    self.pageControl.currentPage = page;
}