iOS UICollectionView 實現卡片效果
阿新 • • 發佈:2018-11-13
現在使用卡片效果的app很多,之前公司讓實現一種卡片效果,就寫了一篇關於實現卡片的文章。文章最後附有demo
實現上我選擇了使用UICollectionView ;用UICollectionViewFlowLayout來定製樣式;下面看看具體實現
具體實現
1、建立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、實現具體代理方法 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; } // 返回每個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點選事件 - (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{ CollModel *infoModel = self.modelArray[indexPath.row]; NSLog(@"infoModelArray----%@",infoModel.title); }
3、自定義UICollectionViewFlowLayout
LHLeftCollocationView.m 實現
#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; //垂直縮放除以係數 CGFloat ScaleFactor = 0.50; //縮放係數 越大縮放越大 - (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); //底部顯示效果 attributes.frame = CGRectMake(attributes.frame.origin.x, attributes.frame.origin.y + zoom, attributes.size.width, attributes.size.height); //居中顯示效果 // 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; } ////設定放大動畫 //-(NSArray<UICollectionViewLayoutAttributes *> *)layoutAttributesForElementsInRect:(CGRect)rect //{ // NSArray *arr = [self getCopyOfAttributes:[super layoutAttributesForElementsInRect:rect]]; // //螢幕中線 // CGFloat centerX = self.collectionView.contentOffset.x + self.collectionView.bounds.size.width/2.0f; // //重新整理cell縮放 // for (UICollectionViewLayoutAttributes *attributes in arr) { // CGFloat distance = fabs(attributes.center.x - centerX); // //移動的距離和螢幕寬度的的比例 // CGFloat apartScale = distance/self.collectionView.bounds.size.width; // //把卡片移動範圍固定到 -π/4到 +π/4這一個範圍內 // CGFloat scale = fabs(cos(apartScale * M_PI/4)); // //設定cell的縮放 按照餘弦函式曲線 越居中越趨近於1 // attributes.transform = CGAffineTransformMakeScale(1.0, scale); // } // return arr; //} //防止報錯 先複製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、自定義cell 和model
model
#import <Foundation/Foundation.h>
@interface CollModel : NSObject
@property (nonatomic,strong)NSString *imgUrl;
@property (nonatomic,strong)NSString *title;
@property (nonatomic,strong)NSString *url;
@end
cell 自定義
#import <UIKit/UIKit.h>
#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()
/**
* 存放所有下載操作的佇列
*/
@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
執行效果