使用collectionView做一個簡單的相簿滑動demo

首先建立一個LineFlowLayout

LineFlowLayout.h

@interface LineFlowLayout : UICollectionViewFlowLayout

@end

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#import "LineFlowLayout.h"

@implementation LineFlowLayout

//初始化時會呼叫

- (instancetype)init{

if(self = [superinit

self.itemSize =CGSizeMake(150,150);

self.scrollDirection =UICollectionViewScrollDirectionHorizontal;

self.minimumInteritemSpacing =50;

self.minimumLineSpacing =50;

    }

returnself;

}

//當UIcollectionView只要一滑動就會詢問是否重新整理介面

//重新整理介面時會呼叫 layoutAttributesForElementsInRect方法

- (BOOL)shouldInvalidateLayoutForBoundsChange:(

returnYES;

}

- (NSArray<UICollectionViewLayoutAttributes *> *)layoutAttributesForElementsInRect:(CGRect)rect{

//    CGFloat centerX = self.collectionView.center.x;

CGFloat screenCenterX =self.collectionView.contentOffset.x +self.collectionView.bounds.size.width * 0.5;

//

NSArray *array = [superlayoutAttributesForElementsInRect:rect];

for (UICollectionViewLayoutAttributes *attrsin array) {

//ABS 取絕對值方法

CGFloat offset = ABS(screenCenterX - attrs.center.x);

        offset = offset / 100;

CGFloat scale =1.0 + 0.5 * (1.0 - offset);

//形變屬性

        attrs.transform =CGAffineTransformMakeScale(scale, scale);

    }

return array;

}

@end

#import "ViewController.h"

#import "LineFlowLayout.h"

@interfaceViewController ()<UICollectionViewDataSource>

@end

@implementation ViewController

- (void)viewDidLoad {

    [superviewDidLoad];

LineFlowLayout *layout = [[LineFlowLayoutalloc] init];

UICollectionView *collectionView = [[UICollectionViewalloc] initWithFrame:CGRectMake(0,200, self.view.frame.size.width,300) collectionViewLayout:layout];

    [self.viewaddSubview:collectionView];

    collectionView.dataSource =self;

NSString *ID = @"cell";

    [collectionView registerClass:[UICollectionViewCellclass] forCellWithReuseIdentifier:ID];

}

#pragma mark -- UICollectionViewDataSource 資料來源方法

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{

return50;

}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{

NSString *ID = @"cell";

UICollectionViewCell *cell = [collectionViewdequeueReusableCellWithReuseIdentifier:IDforIndexPath:indexPath];

    cell.backgroundColor = [UIColorredColor];

return cell;

}

@end