#import "ViewController.h"

#define ImageCount 10#define SCREEN_WIDTH [UIScreen mainScreen].bounds.size.width#define SCREEN_HEIGHT [UIScreen mainScreen].bounds.size.height ViewController ()<UIScrollViewDelegate>{     UIScrollView *_scrollView;    UIImageView *_leftImageView;    UIImageView *_middleImageView;    UIImageView *_rightImageView;    int currentImage;        UIPageControl *_pageControl;} @implementation ViewController- (void)viewDidLoad {     [super viewDidLoad];        _scrollView = [[UIScrollView alloc]initWithFrame:[UIScreen mainScreen].bounds];    [self.view addSubview:_scrollView];        _scrollView.delegate = self;    _scrollView.contentSize = CGSizeMake(_scrollView.frame.size.width*3, _scrollView.frame.size.height);    //设置当前scrollView显示中间区域    _scrollView.contentOffset = CGPointMake(_scrollView.frame.size.width, 0);        _scrollView.pagingEnabled = YES;        //添加imageView    //左    _leftImageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT)];    _leftImageView.contentMode = UIViewContentModeScaleAspectFill;    [_scrollView addSubview:_leftImageView];    //右    _rightImageView = [[UIImageView alloc]initWithFrame:CGRectMake(SCREEN_WIDTH*2, 0, SCREEN_WIDTH, SCREEN_HEIGHT)];    _rightImageView.contentMode = UIViewContentModeScaleAspectFill;    [_scrollView addSubview:_rightImageView];    //中    _middleImageView = [[UIImageView alloc]initWithFrame:CGRectMake(SCREEN_WIDTH, 0, SCREEN_WIDTH, SCREEN_HEIGHT)];    _middleImageView.contentMode = UIViewContentModeScaleAspectFill;    [_scrollView addSubview:_middleImageView];        currentImage = 0;        //初始化pageControl    _pageControl = [[UIPageControl alloc]init];    //根据页数返回pageControl合适的大小    CGSize size = [_pageControl sizeForNumberOfPages:ImageCount];    _pageControl.center = CGPointMake(SCREEN_WIDTH/2, 580);    _pageControl.bounds = CGRectMake(0, 0, size.width, size.height);//    _pageControl.backgroundColor = [UIColor whiteColor];    //设置颜色    _pageControl.pageIndicatorTintColor = [UIColor redColor];    _pageControl.currentPageIndicatorTintColor = [UIColor grayColor];    _pageControl.numberOfPages = ImageCount;    _pageControl.currentPage = currentImage;    [self.view addSubview:_pageControl];            [self setImage];        [NSTimer scheduledTimerWithTimeInterval:2.0f target:self selector:@selector(changeImage) userInfo:nil repeats:YES];    }-(void)changeImage{     [UIView beginAnimations:nil context:nil];    [UIView setAnimationDuration:1.0f];    _scrollView.contentOffset = CGPointMake(SCREEN_WIDTH*2, 0);    [UIView commitAnimations];    currentImage = (currentImage+1)%ImageCount;    _scrollView.contentOffset = CGPointMake(SCREEN_WIDTH, 0);    [self setImage];}-(void) setImage{      _pageControl.currentPage = currentImage;//    加载默认图片    _leftImageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"%d",(ImageCount+currentImage-1)%ImageCount]];    _rightImageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"%d",(currentImage+1)%ImageCount]];    _middleImageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"%d",currentImage]];}-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{     //如果向右滑动    if (scrollView.contentOffset.x == SCREEN_WIDTH*2) {         currentImage = (currentImage+1)%ImageCount;        scrollView.contentOffset = CGPointMake(SCREEN_WIDTH, 0);        [self setImage];    }    //如果向左滑动    else if(scrollView.contentOffset.x == 0)    {         currentImage = (ImageCount+currentImage-1)%ImageCount;        scrollView.contentOffset = CGPointMake(SCREEN_WIDTH, 0);        [self setImage];    }}