在项目中把banner图片UIImageView一张一张的放入UIScrollView中，通过设置UIScrollView的pagingEnabled属性为YES，则可以做到当用户滑动banner时图片一张一张的显示，但当用户想从第一张图到最后一张图，或者从最后一张图到第一张图的时候就会卡住，简单点的做法就是判断用户swipe的方向，然后让UIScrollView自动滑动到最后一张或者第一张，这样做在动画中又显得不够自然，一下是解决办法

　　假设banner图片有3张，在banner的UIScrollView中用以下的方式进行排列

UIScrollView默认滚动到第二张图片的位置，当用户滑动到第一张时，则UIScrollView自动滚动到第4张去，同理当用户滑动到最后一张时，UIScrollView自动滚动到第二张去，这些滚动都设置动画效果为NO

代码如下

h文件

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@PRoperty (weak, nonatomic) IBOutlet UIScrollView *mainScroll;
@property (weak, nonatomic) IBOutlet UIPageControl *pageControl;

@end

m文件

#import "ViewController.h"

@interface ViewController ()<UIScrollViewDelegate>
{
    CGFloat w;
    NSMutableArray *imgArr;
    NSMutableArray *pageArr;
}

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    w = self.view.frame.size.width;
    //page的个数
    pageArr = [NSMutableArray array];
    for (int i = 1; i <= 3; i++) {
        [pageArr addObject:[NSString stringWithFormat:@"%d.jpg",i]];
    }
    //重新获取imgView的个数，将显示的第最后一张图片放在第一张，而在最后一张放置显示的第一张图片
    imgArr = [NSMutableArray array];
    [imgArr addObject:pageArr[pageArr.count - 1]];
    for (NSString *imgSrc in pageArr) {
        [imgArr addObject:imgSrc];
    }
    [imgArr addObject:pageArr[0]];
    self.mainScroll.contentSize = CGSizeMake(w*imgArr.count, 0);
    //开始塞入图片
    for (int i = 0; i < imgArr.count; i++) {
        NSString *imgSrc = imgArr[i];
        UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(i*w, 0, w, self.mainScroll.frame.size.height)];
        [imgView setImage:[UIImage imageNamed:imgSrc]];
        [self.mainScroll addSubview:imgView];
    }
    self.pageControl.numberOfPages = pageArr.count;
    self.mainScroll.bounces = NO;
    self.mainScroll.pagingEnabled = YES;
    self.mainScroll.showsHorizontalScrollIndicator = NO;
    self.mainScroll.showsVerticalScrollIndicator = NO;
    self.mainScroll.delegate = self;
    //自动将scrollView移动显示的第一张图片处
    [self.mainScroll setContentOffset:CGPointMake(w, 0) animated:NO];
}

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
    CGFloat offsetX = scrollView.contentOffset.x;
    int index = offsetX/w;
    if (index == 0) {
        [self.mainScroll setContentOffset:CGPointMake(w*(imgArr.count-2), 0) animated:NO];
        self.pageControl.currentPage = pageArr.count - 1;
    }else if (index == imgArr.count -1){
        [self.mainScroll setContentOffset:CGPointMake(w, 0) animated:NO];
        self.pageControl.currentPage = 0;
    }else{
        self.pageControl.currentPage = index - 1;
    }
    
}



@end