ScrollView的循环播放

1、封装Scrollview代码.h：

//  WHScrollAndPageView.h
//  循环滚动视图
//

#import <UIKit/UIKit.h>

@protocol WHcrollViewViewDelegate;

@interface WHScrollAndPageView : UIView <UIScrollViewDelegate>
{
    __unsafe_unretained id <WHcrollViewViewDelegate> _delegate;
}

@property (nonatomic, assign) id <WHcrollViewViewDelegate> delegate;

@property (nonatomic, assign) NSInteger currentPage;

@property (nonatomic, strong) NSMutableArray *imageViewAry;

@property (nonatomic, readonly) UIScrollView *scrollView;

@property (nonatomic, readonly) UIPageControl *pageControl;

-(void)shouldAutoShow:(BOOL)shouldStart;

@end

@protocol WHcrollViewViewDelegate <NSObject>

@optional
- (void)didClickPage:(WHScrollAndPageView *)view atIndex:(NSInteger)index;

@end

2、封装Scrollview代码.m:

//  WHScrollAndPageView.m
//  循环滚动视图
//
#import "WHScrollAndPageView.h"

@interface WHScrollAndPageView ()
{
    UIView *_firstView;
    UIView *_middleView;
    UIView *_lastView;
    
    float _viewWidth;
    float _viewHeight;
    
    NSTimer *_autoScrollTimer;
    
    UITapGestureRecognizer *_tap;
}

@end

@implementation WHScrollAndPageView

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
    
        _viewWidth = self.bounds.size.width;
        _viewHeight = self.bounds.size.height;
        
        //设置scrollview
        _scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, _viewWidth, _viewHeight)];
        _scrollView.delegate = self;
        _scrollView.contentSize = CGSizeMake(_viewWidth * 3, _viewHeight);
        _scrollView.showsHorizontalScrollIndicator = NO;
        _scrollView.pagingEnabled = YES;
        _scrollView.backgroundColor = [UIColor blackColor];
        _scrollView.delegate = self;
        [self addSubview:_scrollView];
        
        //设置分页
        _pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(0, _viewHeight-30, _viewWidth, 30)];
        _pageControl.userInteractionEnabled = NO;
        _pageControl.currentPageIndicatorTintColor = [UIColor redColor];
        _pageControl.pageIndicatorTintColor = [UIColor whiteColor];
        [self addSubview:_pageControl];
        
        //设置单击手势
        _tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(handleTap:)];
        _tap.numberOfTapsRequired = 1;
        _tap.numberOfTouchesRequired = 1;
        [_scrollView addGestureRecognizer:_tap];
    }
    return self;
}

#pragma mark 单击手势
-(void)handleTap:(UITapGestureRecognizer*)sender
{
    if ([_delegate respondsToSelector:@selector(didClickPage:atIndex:)]) {
        [_delegate didClickPage:self atIndex:_currentPage+1];
    }
}

#pragma mark 设置imageViewAry
-(void)setImageViewAry:(NSMutableArray *)imageViewAry
{
    if (imageViewAry) {
        _imageViewAry = imageViewAry;
        _currentPage = 0; //默认为第0页
        
        _pageControl.numberOfPages = _imageViewAry.count;
    }
    
    [self reloadData];
}

#pragma mark 刷新view页面
-(void)reloadData
{
    [_firstView removeFromSuperview];
    [_middleView removeFromSuperview];
    [_lastView removeFromSuperview];
    
    //从数组中取到对应的图片view加到已定义的三个view中
    if (_currentPage==0) {
        _firstView = [_imageViewAry lastObject];
        _middleView = [_imageViewAry objectAtIndex:_currentPage];
        _lastView = [_imageViewAry objectAtIndex:_currentPage+1];
    }
    else if (_currentPage == _imageViewAry.count-1)
    {
        _firstView = [_imageViewAry objectAtIndex:_currentPage-1];
        _middleView = [_imageViewAry objectAtIndex:_currentPage];
        _lastView = [_imageViewAry firstObject];
    }
    else
    {
        _firstView = [_imageViewAry objectAtIndex:_currentPage-1];
        _middleView = [_imageViewAry objectAtIndex:_currentPage];
        _lastView = [_imageViewAry objectAtIndex:_currentPage+1];
    }
    
    //设置三个view的frame，加到scrollview上
    _firstView.frame = CGRectMake(0, 0, _viewWidth, _viewHeight);
    _middleView.frame = CGRectMake(_viewWidth, 0, _viewWidth, _viewHeight);
    _lastView.frame = CGRectMake(_viewWidth*2, 0, _viewWidth, _viewHeight);
    [_scrollView addSubview:_firstView];
    [_scrollView addSubview:_middleView];
    [_scrollView addSubview:_lastView];
    
    //设置当前的分页
    _pageControl.currentPage = _currentPage;
    
    //显示中间页
    _scrollView.contentOffset = CGPointMake(_viewWidth, 0);
}

#pragma mark scrollvie停止滑动
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    //手动滑动时候暂停自动替换
    [_autoScrollTimer invalidate];
    _autoScrollTimer = nil;
    _autoScrollTimer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(autoShowNextImage) userInfo:nil repeats:YES];
    
    //得到当前页数
    float x = _scrollView.contentOffset.x;
    
    //往前翻
    if (x<=0) {
        if (_currentPage-1<0) {
            _currentPage = _imageViewAry.count-1;
        }else{
            _currentPage --;
        }
    }
    
    //往后翻
    if (x>=_viewWidth*2) {
        if (_currentPage==_imageViewAry.count-1) {
            _currentPage = 0;
        }else{
            _currentPage ++;
        }
    }
    
    [self reloadData];
}

#pragma mark 自动滚动
-(void)shouldAutoShow:(BOOL)shouldStart
{
    if (shouldStart)  //开启自动翻页
    {
        if (!_autoScrollTimer) {
            _autoScrollTimer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(autoShowNextImage) userInfo:nil repeats:YES];
        }
    }
    else   //关闭自动翻页
    {
        if (_autoScrollTimer.isValid) {
            [_autoScrollTimer invalidate];
            _autoScrollTimer = nil;
        }
    }
}

#pragma mark 展示下一页
-(void)autoShowNextImage
{
    if (_currentPage == _imageViewAry.count-1) {
        _currentPage = 0;
    }else{
        _currentPage ++;
    }
    
    [self reloadData];
}

@end

3、使用封装好的Scrollview代码.m:

//  ViewController.m
//  循环滚动视图
//
#import "ViewController.h"
#import "WHScrollAndPageView.h"
#define NUM 10

@interface ViewController ()<WHcrollViewViewDelegate>
{
    WHScrollAndPageView *_whView;
}

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    //创建view （view中包含UIScrollView、UIPageControl，设置frame）
    _whView = [[WHScrollAndPageView alloc] initWithFrame:CGRectMake(0, 44, 320, 400)];
    
    //把N张图片放到imageview上
    NSMutableArray *tempAry = [NSMutableArray array];
    for (int i=1; i<NUM; i++) {
        UIImageView *imageView = [[UIImageView alloc] init];
        imageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"image%i.jpg",i]];
        [tempAry addObject:imageView];
    }
    
    //把imageView数组存到whView里
    [_whView setImageViewAry:tempAry];
    
    //把图片展示的view加到当前页面
    [self.view addSubview:_whView];
    
    //开启自动翻页
    [_whView shouldAutoShow:YES];
    
    //遵守协议
    _whView.delegate = self;
}

#pragma mark 协议里面方法，点击某一页
-(void)didClickPage:(WHScrollAndPageView *)view atIndex:(NSInteger)index
{
    NSLog(@"点击了第%li页",index);
}

#pragma mark 界面消失的时候，停止自动滚动
-(void)viewDidDisappear:(BOOL)animated
{
    [_whView shouldAutoShow:NO];
}

@end