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这篇文章主要讲解了iOS UICollectionView如何实现卡片效果,内容清晰明了,对此有兴趣的小伙伴可以学习一下,相信大家阅读完之后会有帮助。
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具体实现
1、创建UICollectionView
- (void)createCollectionView { CGFloat pading = 0 * SCREEN_WIDTH/375; LHLeftCollocationView * layout = [[LHLeftCollocationView alloc]init]; layout.scrollDirection = UICollectionViewScrollDirectionHorizontal; layout.minimumLineSpacing = pading; layout.minimumInteritemSpacing = pading; // UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc]init]; // layout.scrollDirection = UICollectionViewScrollDirectionHorizontal; _collectionView3 = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 100, [UIScreen mainScreen].bounds.size.width, imageHeight * SCREEN_RATE) collectionViewLayout:layout]; _collectionView3.tag = 33; _collectionView3.dataSource = self; _collectionView3.delegate = self; _collectionView3.bounces = NO; _collectionView3.alwaysBounceHorizontal = NO; _collectionView3.alwaysBounceVertical = NO; _collectionView3.backgroundColor = [UIColor grayColor]; _collectionView3.showsHorizontalScrollIndicator = NO; _collectionView3.showsVerticalScrollIndicator = NO; [self.view addSubview:_collectionView3]; [_collectionView3 registerClass:[CollectionViewCell class] forCellWithReuseIdentifier:collectionViewCell]; }
2、实现具体代理方法 UICollectionViewDelegate,UICollectionViewDataSource
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{ return self.modelArray.count; } - (NSMutableArray *)modelArray { if (!_modelArray) { _modelArray = [NSMutableArray array]; } return _modelArray; } - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath { CollModel *infoModel = self.modelArray[indexPath.row]; NSLog(@"section:%ld --- row:%ld -----%@",indexPath.section,indexPath.row,infoModel.title); CollectionViewCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier:collectionViewCell forIndexPath:indexPath]; cell.itemModel = infoModel; return cell; } // 返回每个item的大小 - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath { CGFloat CWidth = 80 * SCREEN_RATE; CGFloat CHeight = 80 * SCREEN_RATE; return CGSizeMake(CWidth, CHeight); } #pragma mark - UICollectionViewDelegate点击事件 - (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{ CollModel *infoModel = self.modelArray[indexPath.row]; NSLog(@"infoModelArray----%@",infoModel.title); }
3、自定义UICollectionViewFlowLayout
LHLeftCollocationView.m 实现
#import "LHLeftCollocationView.h" @implementation LHLeftCollocationView - (CGPoint)targetContentOffsetForProposedContentOffset:(CGPoint)proposedContentOffset withScrollingVelocity:(CGPoint)velocity { CGRect targectRect = CGRectMake(proposedContentOffset.x, 0.0, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height); NSArray * attriArray = [super layoutAttributesForElementsInRect:targectRect]; CGFloat horizontalCenterX = proposedContentOffset.x + ([UIScreen mainScreen].bounds.size.width); CGFloat offsetAdjustment = CGFLOAT_MAX; for (UICollectionViewLayoutAttributes * layoutAttributes in attriArray) { CGFloat itemHorizontalCenterX = layoutAttributes.center.x; if (fabs(itemHorizontalCenterX-horizontalCenterX) < fabs(offsetAdjustment)) { offsetAdjustment = itemHorizontalCenterX - horizontalCenterX; } } return CGPointMake(proposedContentOffset.x , proposedContentOffset.y); } CGFloat ActiveDistance = 400; //垂直缩放除以系数 CGFloat ScaleFactor = 0.50; //缩放系数 越大缩放越大 - (NSArray*)layoutAttributesForElementsInRect:(CGRect)rect { NSArray * array = [super layoutAttributesForElementsInRect:rect]; CGRect visibleRect = CGRectZero; visibleRect.origin = self.collectionView.contentOffset; visibleRect.size = self.collectionView.bounds.size; for (UICollectionViewLayoutAttributes *attributes in array) { CGFloat distance = CGRectGetMidX(visibleRect) - attributes.center.x; CGFloat normalizedDistance = fabs(distance / ActiveDistance); CGFloat zoom = 1 - ScaleFactor * normalizedDistance; NSLog(@"zoom----%f",zoom); attributes.transform3D = CATransform3DMakeScale(1.0, zoom, 1.0); //底部显示效果 attributes.frame = CGRectMake(attributes.frame.origin.x, attributes.frame.origin.y + zoom, attributes.size.width, attributes.size.height); //居中显示效果 // CGFloat scrollDirectionItemHeight = self.itemSize.height; // CGFloat sideItemFixedOffset = 0; // sideItemFixedOffset = (scrollDirectionItemHeight - scrollDirectionItemHeight * 0.7) / 2; // attributes.center = CGPointMake(attributes.center.x, attributes.center.y + zoom); } return array; } ////设置放大动画 //-(NSArray *)layoutAttributesForElementsInRect:(CGRect)rect //{ // NSArray *arr = [self getCopyOfAttributes:[super layoutAttributesForElementsInRect:rect]]; // //屏幕中线 // CGFloat centerX = self.collectionView.contentOffset.x + self.collectionView.bounds.size.width/2.0f; // //刷新cell缩放 // for (UICollectionViewLayoutAttributes *attributes in arr) { // CGFloat distance = fabs(attributes.center.x - centerX); // //移动的距离和屏幕宽度的的比例 // CGFloat apartScale = distance/self.collectionView.bounds.size.width; // //把卡片移动范围固定到 -π/4到 +π/4这一个范围内 // CGFloat scale = fabs(cos(apartScale * M_PI/4)); // //设置cell的缩放 按照余弦函数曲线 越居中越趋近于1 // attributes.transform = CGAffineTransformMakeScale(1.0, scale); // } // return arr; //} //防止报错 先复制attributes - (NSArray *)getCopyOfAttributes:(NSArray *)attributes { NSMutableArray *copyArr = [NSMutableArray new]; for (UICollectionViewLayoutAttributes *attribute in attributes) { [copyArr addObject:[attribute copy]]; } return copyArr; } - (BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds { return true; } @end
4、自定义cell 和model
model
#import@interface CollModel : NSObject @property (nonatomic,strong)NSString *imgUrl; @property (nonatomic,strong)NSString *title; @property (nonatomic,strong)NSString *url; @end
cell 自定义
#import#import "CollModel.h" @interface CollectionViewCell : UICollectionViewCell @property (nonatomic, strong) CollModel * itemModel; @end #import "CollectionViewCell.h" #define SCREEN_RATE ([UIScreen mainScreen].bounds.size.width/375.0) @interface CollectionViewCell() /** * 存放所有下载操作的队列 */ @property (nonatomic, strong) UIImageView *itemIcon; @property (nonatomic, strong) UILabel *itemLabel; @property (nonatomic, strong) UILabel *priceLabel; @end @implementation CollectionViewCell @synthesize itemModel = _itemModel; - (instancetype)initWithFrame:(CGRect)frame { if (self = [super initWithFrame:frame]) { self.contentView.backgroundColor = [UIColor clearColor]; [self initView]; } return self; } - (void)initView { _itemIcon = [[UIImageView alloc] init]; [self.contentView addSubview:_itemIcon]; _itemIcon.backgroundColor = [UIColor clearColor]; // CGFloat iconWidth = ([UIScreen mainScreen].bounds.size.width / 5.0) * SCREEN_RATE; _itemIcon.frame = CGRectMake(0, 0, self.contentView.frame.size.width, self.contentView.frame.size.height); _itemIcon.center = self.contentView.center; } - (CollModel *)itemModel { return _itemModel; } - (void)setItemModel:(CollModel *)itemModel { if (!itemModel) { return; } _itemModel = itemModel; [self setCellWithModel:_itemModel]; } - (void)setCellWithModel:(CollModel *)itemModel { [[NSOperationQueue mainQueue] addOperationWithBlock:^{ _itemIcon.image = [UIImage imageNamed:itemModel.url]; }]; } @end
运行效果
看完上述内容,是不是对iOS UICollectionView如何实现卡片效果有进一步的了解,如果还想学习更多内容,欢迎关注创新互联行业资讯频道。