iOS UICollectionView实现卡片效果-移动开发

这篇文章主要为大家详细介绍了iOS UICollectionView实现卡片效果，文中示例代码介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们可以参考一下

现在使用卡片效果的app很多，之前公司让实现一种卡片效果，就写了一篇关于实现卡片的文章。文章最后附有demo

实现上我选择了使用UICollectionView ；用UICollectionViewFlowLayout来定制样式；下面看看具体实现

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<UICollectionViewLayoutAttributes *> *)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<UICollectionViewLayoutAttributes *> *)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;
/