iOS 轮播图-循环播放图片

直接上代码，有注释

//
//  ViewController.m
//  SlipPicture
//
//  Created by chenqianfeng on 15/12/7.
//  Copyright © 2015年 chenqianfeng. All rights reserved.
//
#import "ViewController.h"
@interface ViewController (){
    UIScrollView *_sView;
    UIPageControl *_pgControler;
    NSArray *_imageArr;
}
@end
@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
    //创建数据
    [self createImageArr];
    //创建ScrollView
    [self creatScrollView];
    //创建Pagecontroller
    [self createPagecontroller];
}
- (void)createImageArr
{
    _imageArr = [[NSArray alloc]initWithObjects:@"3",@"0",@"1",@"2",@"3",@"0", nil];
}
- (void)creatScrollView
{
    _sView = [[UIScrollView alloc]initWithFrame:CGRectMake(0, 100,[UIScreen mainScreen].bounds.size.width, 400)];
    //必须设置contentSize，要不然滚动不了（scrollEnabled默认为YES,可以滚动）
    _sView.contentSize = CGSizeMake(_sView.frame.size.width * _imageArr.count, 0);
    //设置翻页效果
    _sView.pagingEnabled = YES;
    //启动时候设置偏移量显示数组中的第二张图
    _sView.contentOffset = CGPointMake(_sView.frame.size.width, 0);
    //设置代理
    _sView.delegate = self;
    [self.view addSubview:_sView];
    //往ScrollView中加图片、（循环播放，）
    for (int i = 0; i<_imageArr.count; i++) {
        UIImageView *imgView = [[UIImageView alloc]initWithFrame:CGRectMake([UIScreen mainScreen].bounds.size.width * i, 0, [UIScreen mainScreen].bounds.size.width, 400)];
        imgView.image = [UIImage imageNamed:_imageArr[i]];
        [_sView addSubview:imgView];
    }
}
- (void)createPagecontroller
{
    //Pagecontroller
    _pgControler = [[UIPageControl alloc]initWithFrame:CGRectMake(([UIScreen mainScreen].bounds.size.width - 100)/2, 100+200, 100, 40)];
    _pgControler.numberOfPages = 4;//设置Pagecontroller的页数
    _pgControler.currentPage = 0;//设置Pagecontroller的当前页
    _pgControler.backgroundColor = [UIColor blackColor];
    [self.view addSubview:_pgControler];
}
#pragma  mark UIScrollViewDelegate
// scrollview 减速停止
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    if (scrollView.contentOffset.x == 0) {
        //从第一张图向左滑（左边提前放了一张最后一张图，障眼法），设置偏移量使得瞬间跳到最后一张图
        scrollView.contentOffset = CGPointMake(self.view.frame.size.width * (_imageArr.count - 2), 0);
    } else if (scrollView.contentOffset.x == (_imageArr.count - 1)*self.view.frame.size.width){
        //从最后一张图向右滑（右边提前放了一张第一张图，障眼法），设置偏移量使得瞬间跳到第一张图
        scrollView.contentOffset = CGPointMake(self.view.frame.size.width, 0);
    }else{
    }
    //pageController的currentPage
    _pgControler.currentPage = scrollView.contentOffset.x / self.view.frame.size.width - 1;
}
@end