本文实例讲了IOS无限滚动效果，分享给大家供大家参考，具体内容如下
滑动到当前位置时候才去请求，本地有内容则直接显示（以来SDWebImage,UIView+Ext）
HZScrollView.h
#import <UIKit/UIKit.h>typedef void（^HZReturnBlock）（NSInteger index,CGFloat offset）;typedef NS_ENUM（NSUInteger, HZScrollViewPageControllPosition） {HZScrollViewPageControllPositionNone,HZScrollViewPageControllPositionLeft,HZScrollViewPageControllPositionCenter,HZScrollViewPageControllPositionRight,};@class HZScrollView;@protocol HZScrollViewDelegate <NSObject>@optional- （void）resetPosition:（HZScrollView *）scrollView AndIndex:（NSInteger）index;@end@interface HZScrollView : UIView/** * 返回当前位置 */@property （nonatomic, weak）id <HZScrollViewDelegate>delegate;/** * 默认图 */@property （nonatomic, strong） UIImage *hz_placeImage;/** * 图片列表哇 */@property （nonatomic, strong） NSArray *hz_ImageList;/** * pagecongroll 位置 */@property （nonatomic, assign） HZScrollViewPageControllPosition hz_PageControllPosition;/** * 变换自身frame * * @param offset 偏移量 */- （void）transformView:（CGFloat）offset;/** * 获取当前位置以及便宜 * * @param block 返回内容 */- （void）hz_getContent:（HZReturnBlock）block;@endHZScrollView.m
#import "UIImageView+WebCache.h"#import "HZScrollView.h"#import "UIView+DylanFramTool.h"#define HZ_FormatImage（val_imageView）- （UIImageView *）val_imageView{if （！_##val_imageView） {\_##val_imageView = [[UIImageView alloc] init];}
eturn _##val_imageView;}//宽度#define HZ_SWidthself.bounds.size.width//高度#define HZ_SHeightself.bounds.size.height#define HZ_PHeight16@interface HZScrollView （）<UIScrollViewDelegate>@property （nonatomic, copy） HZReturnBlock hz_block;/** * 总数 */@property （nonatomic,assign） NSInteger hz_MaxCount;/** * 当前位置 */@property （nonatomic,assign） NSInteger hz_currentIndex;/** * 容器 */@property （nonatomic, strong） UIScrollView *scrollView;/** * 你懂滴 */@property （nonatomic, strong） UIPageControl *pageControll;/**视图**/@property （nonatomic, strong） UIImageView *leftImageView;@property （nonatomic, strong） UIImageView *centerImageView;@property （nonatomic, strong） UIImageView *rightImageView;@end@implementation HZScrollView{CGRect _hz_Frame;}#pragma mark -#pragma mark - init- （instancetype）initWithFrame:（CGRect）frame{self = [super initWithFrame:frame];if （self） {_hz_Frame = frame;[self addSubview:self.scrollView];[self configImageView];[self addSubview:self.pageControll];}return self;}#pragma mark -#pragma mark - config- （void）configImageView{self.leftImageView.frame = CGRectMake（0, 0, HZ_SWidth, HZ_SHeight）;[self.scrollView addSubview:self.leftImageView];self.centerImageView.frame = CGRectMake（HZ_SWidth, 0, HZ_SWidth, HZ_SHeight）;[self.scrollView addSubview:self.centerImageView];self.rightImageView.frame = CGRectMake（HZ_SWidth * 2, 0, HZ_SWidth, HZ_SHeight）;[self.scrollView addSubview:self.rightImageView];}#pragma mark -#pragma mark - reSet- （void）setHz_placeImage:（UIImage *）hz_placeImage{_hz_placeImage = hz_placeImage;[self changeImageLeft:-1 center:-1 right:-1];if （self.hz_MaxCount） {[self setHz_MaxCount:self.hz_ImageList.count];}}- （void）setHz_ImageList:（NSArray *）hz_ImageList{_hz_ImageList = [hz_ImageList copy];[self setHz_MaxCount:_hz_ImageList.count];}- （void）setHz_MaxCount:（NSInteger）hz_MaxCount{_hz_MaxCount = hz_MaxCount;switch （_hz_MaxCount） {case 0:self.scrollView.scrollEnabled = NO;[self changeImageLeft:-1 center:-1 right:-1];break;case 1:self.scrollView.scrollEnabled = NO;[self changeImageLeft:0 center:0 right:0];break;default:self.scrollView.scrollEnabled = YES;[self changeImageLeft:_hz_MaxCount - 1 center:0 right:1];break;}self.pageControll.numberOfPages = _hz_MaxCount;[self setHz_PageControllPosition:_hz_PageControllPosition];}- （void）setHz_PageControllPosition:（HZScrollViewPageControllPosition）hz_PageControllPosition{_hz_PageControllPosition = hz_PageControllPosition;CGFloat width = self.hz_MaxCount * HZ_PHeight;switch （_hz_PageControllPosition） {case HZScrollViewPageControllPositionNone:self.pageControll.hidden = YES;break;case HZScrollViewPageControllPositionLeft:self.pageControll.hidden = NO;self.pageControll.frame = CGRectMake（10, self.pageControll.frame.origin.y, width, self.pageControll.frame.size.height）;break;case HZScrollViewPageControllPositionCenter:self.pageControll.hidden = NO;self.pageControll.frame = CGRectMake（（self.bounds.size.width - width）/2.f, self.pageControll.frame.origin.y, width, self.pageControll.frame.size.height）;break;case HZScrollViewPageControllPositionRight:self.pageControll.hidden = NO;self.pageControll.frame = CGRectMake（self.bounds.size.width - 10 - width, self.pageControll.frame.origin.y, width, self.pageControll.frame.size.height）;break;default:break;}if （width <= HZ_PHeight） {self.pageControll.hidden = YES;}}#pragma mark -#pragma mark - LZ- （UIScrollView *）scrollView{if （！_scrollView） {_scrollView = [[UIScrollView alloc] initWithFrame:self.bounds];_scrollView.pagingEnabled = YES;_scrollView.showsHorizontalScrollIndicator = NO;_scrollView.delegate = self;_scrollView.contentSize = CGSizeMake（HZ_SWidth * 3,0）;}return _scrollView;}- （UIPageControl *）pageControll{if （！_pageControll） {_pageControll = [[UIPageControl alloc] initWithFrame:CGRectMake（0,HZ_SHeight - HZ_PHeight,HZ_PHeight, 7）];_pageControll.pageIndicatorTintColor = [UIColor lightGrayColor];_pageControll.currentPageIndicatorTintColor = [UIColor whiteColor];_pageControll.numberOfPages = self.hz_MaxCount;_pageControll.currentPage = 0;}return _pageControll;}HZ_FormatImage（leftImageView）;HZ_FormatImage（centerImageView）;HZ_FormatImage（rightImageView）;#pragma mark -#pragma mark - private Method- （void）changeImageWithOffset:（CGFloat）offsetX{if （offsetX >= HZ_SWidth * 2） {self.hz_currentIndex++;if （self.hz_currentIndex == self.hz_MaxCount - 1） {[self changeImageLeft:self.hz_currentIndex - 1 center:self.hz_currentIndex right:0];}else if （self.hz_currentIndex == self.hz_MaxCount） {self.hz_currentIndex = 0;[self changeImageLeft:self.hz_MaxCount - 1 center:0 right:1];}else {[self changeImageLeft:self.hz_currentIndex-1 center:self.hz_currentIndex right:self.hz_currentIndex + 1];}if （self.hz_block） {self.hz_block（self.hz_currentIndex,offsetX）;}self.pageControll.currentPage = self.hz_currentIndex;}if （offsetX <= 0） {self.hz_currentIndex--;if （self.hz_currentIndex == 0） {[self changeImageLeft:self.hz_MaxCount-1 center:0 right:1];}else if （self.hz_currentIndex == -1） {self.hz_currentIndex = self.hz_MaxCount-1;[self changeImageLeft:self.hz_currentIndex-1 center:self.hz_currentIndex right:0];}else {[self changeImageLeft:self.hz_currentIndex-1 center:self.hz_currentIndex right:self.hz_currentIndex+1];}if （self.hz_block） {self.hz_block（self.hz_currentIndex,offsetX）;}self.pageControll.currentPage = self.hz_currentIndex;}[self setHz_PageControllPosition:_hz_PageControllPosition];}- （void）changeImageLeft:（NSInteger）leftIndex center:（NSInteger）centerIndex right:（NSInteger）rightIndex{if （self.hz_currentIndex > self.hz_MaxCount） {return;}if （leftIndex == -1 && centerIndex == -1 && rightIndex == -1） {self.leftImageView.image = self.hz_placeImage;self.centerImageView.image = self.hz_placeImage;self.rightImageView.image = self.hz_placeImage;} else {[self checkExistImage:self.hz_ImageList[leftIndex]ImageView:self.leftImageView CurrentIndex:@（leftIndex）];[self checkExistImage:self.hz_ImageList[centerIndex]ImageView:self.centerImageView CurrentIndex:@（centerIndex）] ;[self checkExistImage:self.hz_ImageList[rightIndex]ImageView:self.rightImageView CurrentIndex:@（rightIndex）];}[self.scrollView setContentOffset:CGPointMake（HZ_SWidth, 0）];}- （void）checkExistImage:（NSString *）urlString ImageView:（UIImageView *）currentImageViewCurrentIndex:（NSNumber *）index{if （[[[SDWebImageManager sharedManager] imageCache] imageFromDiskCacheForKey:urlString]）{currentImageView.image = [[[SDWebImageManager sharedManager] imageCache] imageFromMemoryCacheForKey:urlString];return;} else {currentImageView.image = self.hz_placeImage;if （self.hz_currentIndex ！= [index integerValue]） {return;}[self performSelector:@selector（downLoadImage:） withObject:@[urlString,currentImageView] afterDelay:0 inModes:@[NSDefaultRunLoopMode]];}}- （void）downLoadImage:（NSArray *）param{NSString *urlString = [param firstObject];__weak UIImageView *currentImageView = [param lastObject];[[SDWebImageManager sharedManager] downloadImageWithURL:[NSURL URLWithString:urlString] options:0 progress:^（NSInteger receivedSize, NSInteger expectedSize） {NSLog（@"received:%@",@（receivedSize））;} completed:^（UIImage *image, NSError *error, SDImageCacheType cacheType, BOOL finished, NSURL *imageURL） {currentImageView.image = image;//[[[SDWebImageManager sharedManager] imageCache] storeImage:image forKey:urlString];[[[SDWebImageManager sharedManager] imageCache] storeImage:image forKey:urlString toDisk:YES];}];}#pragma mark -#pragma mark - UIScrollViewDelegate- （void）scrollViewDidScroll:（UIScrollView *）scrollView{[self changeImageWithOffset:scrollView.contentOffset.x];}- （void）scrollViewDidEndDecelerating:（UIScrollView *）scrollView{NSInteger index = scrollView.contentOffset.x/scrollView.width;if （[self.delegate respondsToSelector:@selector（resetPosition:AndIndex:）]） {[self.delegate resetPosition:self AndIndex:self.hz_currentIndex];}}#pragma mark -#pragma mark - public method- （void）transformView:（CGFloat）offset{if （offset > 0） {return;}CGFloat currentHeight = 210 - offset;self.height = currentHeight ;CGFloat currentScale = currentHeight / _hz_Frame.size.height;self.left = _hz_Frame.origin.x - （_hz_Frame.size.width * currentScale - _hz_Frame.size.width）/2.f;self.width = _hz_Frame.size.width * currentScale;self.top = offset;self.scrollView.size = self.size;self.leftImageView.size = self.size;self.centerImageView.size = self.size;self.rightImageView.size = self.size;self.centerImageView.x = self.width;self.rightImageView.x = self.width * 2;self.scrollView.contentSize = CGSizeMake（self.width *3, self.height）;[self.scrollView setContentOffset:CGPointMake（HZ_SWidth, 0）];}- （void）hz_getContent:（HZReturnBlock）block{self.hz_block = block;}- （void）layoutSubviews{[super layoutSubviews];}@end以上就是本文的全部内容，希望对大家的学习有所帮助。
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