一句代码搞定无限图片轮播器,抽取API

项目介绍：

最近闲来无事,封装了一个无限图片轮播器,基于collectionView完成,抽取了两个API,一个是创建轮播器,一个是点击图片的跳转,使用的话,直接把JZLCycleView这个文件夹拖进项目,调用API就完成了,非常简单。

1.无限轮播思路:
建了图片数量*3个数的cell,然后去一直显示中间的cell,到最后一组的第一个,无动画滚动到中间一组的第一个,到第一组的最后一个,无动画滚动到中间一组的最后一个

2.调用的方法,使用直接调用API

_cycleView = [JZLCycleView cycleCollectionViewWithFrame:CGRectMake(0, 0, JZLScreenWidth, JZLCycleViewHeight) PlaceholderImage:[UIImage imageNamed:@'placeholderImage']]; //小圆点颜色设置,自己根据需求更改,默认黑色和白色 _cycleView.pageControl.pageIndicatorTintColor = [UIColor orangeColor]; _cycleView.pageControl.currentPageIndicatorTintColor = [UIColor whiteColor]; //如果要跳转记得遵守协议,设置代理 _cycleView.delegate = self; _cycleView.clickItemBlock = ^(NSInteger index){ NSLog(@'%ld',(long)index); }; [self.view addSubview:_cycleView];

2.1跳转这一块封装了两个,一个block,一个代理,个人认为代理更清晰一些

//block跳转 _cycleView.clickItemBlock = ^(NSInteger index){ NSLog(@'%ld',(long)index); };//代理跳转 - (void)selectItemAtIndex:(NSInteger)index { NSLog(@'%ld',index); }

3.实现
1.初始化轮播器,这里抽取了两个,一个是加载本地图片,一个是加载网路url,一般开发中第二个用的比较多

/** 加载后端获取的url图片 @param frame 图片轮播器的frame @param placeholderImage 占位图 @return 图片轮播图 */ + (instancetype)cycleCollectionViewWithFrame: (CGRect)frame PlaceholderImage: (UIImage *)placeholderImage; /** 加载本地图片 @param frame 图片轮播器frame @param imageArray 本地图片数组(数组里元素为imageView) @param placeholderImage 占位图 @return 图片轮播器 */ + (instancetype)cycleCollectionViewWithFrame: (CGRect)frame imageArray: (NSArray *)imageArray PlaceholderImage: (UIImage *)placeholderImage;

2.主要的就是去完成collectionView

//设置collectionView - (void)setupCollcetionView { //collcetionView UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init]; UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:self.bounds collectionViewLayout:flowLayout]; flowLayout.itemSize = CGSizeMake(self.bounds.size.width, self.bounds.size.height); flowLayout.scrollDirection = UICollectionViewScrollDirectionHorizontal; flowLayout.minimumLineSpacing = 0; collectionView.pagingEnabled = YES; collectionView.bounces = NO; collectionView.showsHorizontalScrollIndicator = NO; collectionView.delegate = self; collectionView.dataSource = self; [collectionView registerClass:[JZLCollectionViewCell class] forCellWithReuseIdentifier: reuseID]; [self addSubview:collectionView]; self.collectionView = collectionView; //pageControl self.pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(self.bounds.size.width / 2 - 50, self.bounds.size.height - 20, 100, 20)]; //默认一张,加载图片后自动更新 self.pageControl.numberOfPages = 1; self.pageControl.currentPage = 0; [self addSubview:self.pageControl]; }

3.添加定时器以及手动滚动和自动滚动的切换

//设置页码 - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView { self.pageControl.currentPage = (NSInteger)(scrollView.contentOffset.x / scrollView.bounds.size.width)%self.imageArray.count; } //添加定时器 - (void)addTimer { self.timer = [NSTimer scheduledTimerWithTimeInterval:automaticTime target:self selector:@selector(automaticScrollCollectionCell) userInfo:nil repeats:YES]; [[NSRunLoop currentRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes]; } //删除定时器 - (void)deleteTimer { [self.timer invalidate]; self.timer = nil; } //自动滚动 - (void)automaticScrollCollectionCell { self.index++; if (self.imageArray.count == 0) { return; }else { NSIndexPath *indexPath = [NSIndexPath indexPathForItem:self.index inSection:0]; [self.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:0 animated:YES]; if (indexPath.row == self.imageArray.count * 2) { dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ NSIndexPath *indexPath = [NSIndexPath indexPathForItem:self.imageArray.count inSection:0]; [self.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:0 animated:NO]; }); } self.pageControl.currentPage = self.index % self.imageArray.count ; } } //手动滚动时删除定时器 - (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView { [self deleteTimer]; if (self.imageArray.count == 0) { return; }else { if (self.index == self.imageArray.count - 1) { [self.collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:self.imageArray.count * 2 - 1 inSection:0] atScrollPosition:0 animated:NO]; } if (self.index == self.imageArray.count * 2) { [self.collectionView scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:self.imageArray.count inSection:0] atScrollPosition:0 animated:NO]; } } } //停止滚动时打开定时器 - (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate { [self addTimer]; } - (void)scrollViewDidScroll:(UIScrollView *)scrollView { self.index = (NSInteger)(scrollView.contentOffset.x / scrollView.bounds.size.width); }

git地址:https://github.com/allenjzl/JZLCycleView.git

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