#import "ViewController.h"

#define IMAGENUMBER  5

#define SIZE  self.view.bounds.size

@interface ViewController ()

{

    UIScrollView *_scrollerView ;

    UIImageView *_leftImageView ;

    UIImageView *_centerImageVIew;

    UIImageView *_rightImagView;

    UIPageControl *_pageCoontroller;

　　//当前索引下标

    NSInteger _curremtIndex;

}

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    self.view.backgroundColor =[UIColor brownColor];

    [self createScrollerView];

}

-(void)createScrollerView

{

    _scrollerView =[[UIScrollView alloc]initWithFrame:[[UIScreen mainScreen]bounds]];

    [self.view addSubview:_scrollerView];

　　//创建左，中，右，三个ImageView视图

    _leftImageView =[[UIImageView alloc]initWithImage:[UIImage imageNamed:@"0.jpg"]];

    _centerImageVIew =[[UIImageView alloc]initWithImage:[UIImage imageNamed:@"1.jpg"]];

    _rightImagView =[[UIImageView alloc]initWithImage:[UIImage imageNamed:@"2.jpg"]];

    _leftImageView.frame =CGRectMake(, , SIZE.width, SIZE.height);

    _centerImageVIew.frame =CGRectMake(SIZE.width, , SIZE.width, SIZE.height);

    _rightImagView.frame =CGRectMake(SIZE.width*, , SIZE.width, SIZE.height);

　　//添加

    [_scrollerView addSubview:_leftImageView];

    [_scrollerView addSubview:_centerImageVIew];

    [_scrollerView addSubview:_rightImagView];

    _scrollerView.contentSize=CGSizeMake(SIZE.width*, SIZE.height);

    _scrollerView.pagingEnabled=YES;

    _scrollerView.delegate=self;

   _scrollerView.contentOffset=CGPointMake(SIZE.width, );

    _scrollerView.showsHorizontalScrollIndicator=NO;

    _scrollerView.showsVerticalScrollIndicator=NO;

　　//页码指示器

    _pageCoontroller =[[UIPageControl alloc]initWithFrame:CGRectMake((SIZE.width-)/, SIZE.height-, SIZE.width-, )];

    _curremtIndex=;

    _pageCoontroller.numberOfPages=IMAGENUMBER;

    _pageCoontroller.backgroundColor=[UIColor clearColor];

    _pageCoontroller.pageIndicatorTintColor=[UIColor orangeColor];

    _pageCoontroller.currentPageIndicatorTintColor=[UIColor purpleColor];

    _pageCoontroller.currentPage=_curremtIndex;

    [_pageCoontroller addTarget:self action:@selector(NextImageClicked) forControlEvents:UIControlEventValueChanged];

    [self.view addSubview:_pageCoontroller];

}

-(void)NextImageClicked

{

    NSInteger pageImage =_pageCoontroller.currentPage;

    if (pageImage==_pageCoontroller.currentPage+) {

        pageImage+=;

    }else{

        pageImage-=;

    }

    _curremtIndex=pageImage;

    _scrollerView.contentOffset=CGPointMake(SIZE.width*pageImage, );

}

-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView

{

    [self loadImage];

    [UIView animateWithDuration:0.5 animations:^{

          _pageCoontroller.currentPage= _curremtIndex;

     }];

}

-(void)loadImage

{

    //创建动画效果

    CATransition *transaction =[[CATransition alloc]init];

    CGPoint offset =_scrollerView.contentOffset;

　　//向右滚动

    if (offset.x>) {

　　　//动画类型

        transaction.type =@"fade";

　　//通过取余运算获取当前索引下标　　

        _curremtIndex=(_curremtIndex+)%IMAGENUMBER;

        NSString *rightImage =[NSString stringWithFormat:@"%li.jpg",_curremtIndex];

        _rightImagView.image=[UIImage imageNamed:rightImage];

    }else{//向左滚动

        transaction.type=@"fade";

        _curremtIndex=(_curremtIndex-+IMAGENUMBER)%IMAGENUMBER;

        NSString *leftImage =[NSString stringWithFormat:@"%li.jpg",_curremtIndex];

        _leftImageView.image=[UIImage imageNamed:leftImage];

    }

　　 //添加动画效果

    [_scrollerView.layer addAnimation:transaction forKey:@"transaction"];

}