IOS 轮播图[增加页码]

#import "ViewController.h"
@interface ViewController () <UIScrollViewDelegate>
@property (weak, nonatomic) IBOutlet UIScrollView *scrollView;
@property (weak, nonatomic) IBOutlet UIPageControl *pageControl;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    int count = 1;
    CGFloat width = self.scrollView.frame.size.width;
    CGFloat height = self.scrollView.frame.size.height;
    //设置滚动尺寸，宽度大于scrollView宽度才能滚动
    self.scrollView.contentSize = CGSizeMake(width * count, height);
    for (int i = 0; i < count; i++) {
        UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:[NSString stringWithFormat:@"%i.jpeg",i]]];
        imageView.frame = CGRectMake(i * width, 0, width, height);
        [self.scrollView addSubview:imageView];
    }
    //scrollView开启分页[IOS内置]
    self.scrollView.pagingEnabled = YES;

    //当轮播图只有一张时，最好是给页码隐藏掉
    if(count <= 1){
        //方式一:设置透明度为透明
        //self.pageControl.alpha = 0;
        //方式二:设置UIView的hidden属性
        //self.pageControl.hidden = YES;
        //方式三:使用pageControl的特有属性hidesForSinglePage
        self.pageControl.hidesForSinglePage = YES;
    }
    //---> 分页功能不需要滚动条，可以用代码，也可以在storyBoard中勾去:showsHorizontalScrollIndicator和showsVerticalScrollIndicator
    //设置分页标识的个数:---> 与轮播图数个数一致
    self.pageControl.numberOfPages = count;
}
//设置结束后正在结束动作
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
    //计算下标索引
    //int index = self.scrollView.contentOffset.x / self.scrollView.frame.size.width;
    //设置当前页码
    //self.pageControl.currentPage = index;
}
//设置结束拖拽后的动作
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{
    if(decelerate == NO){
        //计算下标索引
        //int index = self.scrollView.contentOffset.x / self.scrollView.frame.size.width;
        //设置当前页码
        //self.pageControl.currentPage = index;
    }
}
//另一种方案
-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
    //另一个方案:当图片超过一半显示需要将下标索引进一[四舍五入]
    int index = (self.scrollView.contentOffset.x / self.scrollView.frame.size.width + 0.5);
    self.pageControl.currentPage = index;
}
@end