轮播图为一种常见的方式，常用于各种网站，或者App中，当然，作为APP的启动视图也是不错的选择。

闲时封装了一个，仅供新手参考。

1.新建工程，建立轮播图类

建立一个空的工程，新建一个类，起名为Carousel，继承于UIView

2.编写Carousel类接口

 1 @interface Carousel : UIView
 2 typedef NS_ENUM(NSInteger,UICarouselPageType){
 3     //建立一个枚举型，来设置Carousel的样式
 4     UICarouselPageTypeCenter,//设置pageControl在中心
 5     UICarouselPageTypeLeft,  //设置pageControl在左侧
 6     UICarouselPageTypeRight, //设置pageControl在右侧
 7 };
 8 @property(nonatomic,strong)NSArray *ImageArry;//用于接收来自外部的图片
 9 @property(nonatomic,assign)NSTimeInterval duration;//用于接收每张图片的持续时间
10 @property(nonatomic,assign)UICarouselPageType PageType;
11 @end

3.内部代码

1.用懒加载的方式定义UIScrollView和UIPageControl

(1)为Carousel类建立延展

1 @interface Carousel()<UIScrollViewDelegate>
2 @property(nonatomic,strong)UIScrollView *scroll;
3 @property(nonatomic,strong)UIPageControl *pageControl;
4 @property(nonatomic,assign)int index;
5 @property(nonatomic,strong)NSTimer *timer;
6 @end

(2)重写初始化方法

1 -(instancetype)initWithFrame:(CGRect)frame{
2     self =[super initWithFrame:frame];
3     if (self) {
4         _timer =[[NSTimer alloc]init];
5         _index=0;
6     }
7     return self;
8 }

（3）scrollView

 1 -(UIScrollView *)scroll{
 2     if (_scroll==nil) {
 3         _scroll =[[UIScrollView alloc]initWithFrame:self.bounds];
 4         _scroll.delegate=self;
 5         _scroll.contentSize=CGSizeMake([_ImageArry count]*WIDTH,HEIGHT);
 6         _scroll.pagingEnabled=YES;//允许整页翻动
 7         _scroll.bounces=NO;
 8         _scroll.showsHorizontalScrollIndicator=NO;
 9         _scroll.showsVerticalScrollIndicator=NO;
10         for (int i=0; i<[_ImageArry count]; i++) {
11             UIImageView *imageView =[[UIImageView alloc]initWithFrame:CGRectMake(i*WIDTH, 0, WIDTH, HEIGHT)];
12             UIImage *image=[_ImageArry objectAtIndex:i];
13             imageView.image=image;
14             [_scroll addSubview:imageView];
15         }
16     }
17     return _scroll;
18 }

(4)pageControl

 1 -(UIPageControl *)pageControl{
 2     if (_pageControl ==nil) {
 3         _pageControl =[[UIPageControl alloc]init];
 4         [self setPageControlFrame];
 5         _pageControl.numberOfPages=[_ImageArry count];
 6         _pageControl.pageIndicatorTintColor=[UIColor greenColor];
 7         _pageControl.currentPageIndicatorTintColor=[UIColor redColor];
 8         [_pageControl addTarget:self action:@selector(change:) forControlEvents:UIControlEventValueChanged];
 9     }
10     return _pageControl;
11 }
12 -(void)setPageControlFrame{
13     //当PageType有不同值的时候 有不同的frame
14     if (_PageType==UICarouselPageTypeLeft) {
15         _pageControl.frame=CGRectMake(0,HEIGHT-20,150,20);
16     }else if (_PageType ==UICarouselPageTypeRight){
17         _pageControl.frame=CGRectMake(WIDTH-150,HEIGHT-20,150,20);
18     }else{
19         _pageControl.frame=CGRectMake(WIDTH/2-75,HEIGHT-20,150,20);
20     }
21 }
22 -(void)change:(UIPageControl *)page{
23     [_timer invalidate];
24     _timer=nil;
25     _scroll.contentOffset=CGPointMake(page.currentPage*WIDTH, 0);
26     _index=(int)page.currentPage;//重新给index赋值
27     _timer =[NSTimer scheduledTimerWithTimeInterval:_duration target:self selector:@selector(lunbo) userInfo:nil repeats:YES];
28 }

(5) 重写ImageArray的set方法

1 -(void)setImageArry:(NSArray *)ImageArry{
2     //重写Set方法 当ImageArray有值的时候显示scrollView和PageControl
3     if (_ImageArry!=ImageArry) {
4         _ImageArry =ImageArry;
5         [self addSubview:self.scroll];
6         [self addSubview:self.pageControl];
7         _timer =[NSTimer scheduledTimerWithTimeInterval:_duration target:self selector:@selector(lunbo) userInfo:nil repeats:YES];
8     }
9 }

(6)Scroll的代理方法

 1 -(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
 2     //开始拖动时销毁计时器
 3     [_timer invalidate];
 4     _timer =nil;
 5 }
 6 -(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
 7     //减速结束时重新生成计时器
 8     _index=(int)_pageControl.currentPage;//重新给index赋值
 9     _timer =[NSTimer scheduledTimerWithTimeInterval:_duration target:self selector:@selector(lunbo) userInfo:nil repeats:YES];
10 }
11 -(void)scrollViewDidScroll:(UIScrollView *)scrollView{
12     _pageControl.currentPage=scrollView.contentOffset.x/WIDTH;
13 }

4.应用Carousel类

 1 #import "ViewController.h"
 2 #import "Carousel.h"
 3 @interface ViewController ()
 4 @end
 5 @implementation ViewController
 6
 7 - (void)viewDidLoad {
 8     [super viewDidLoad];
 9     Carousel *lunbo =[[Carousel alloc]initWithFrame:CGRectMake(0, 100, 414, 300)];
10     NSMutableArray *arr=[[NSMutableArray alloc]initWithCapacity:9];
11     for (int index=1; index<10; index++) {
12         UIImage *image =[UIImage imageNamed:[NSString stringWithFormat:@"%d.jpg",index]];
13         [arr addObject:image];
14     }
15     lunbo.duration=1;
16     lunbo.PageType=UICarouselPageTypeCenter;
17     lunbo.ImageArry=arr;
18     [self.view addSubview:lunbo];
19     // Do any additional setup after loading the view, typically from a nib.
20 }

效果图：