滚动CollectionView控制PageControl实现分页浏览的效果

来源：互联网发布：房租占收入比例知乎编辑：程序博客网时间：2024/04/27 05:50

#pragma mark -- 主要实现在于自定义UICollectionViewFlowLayout

#pragma mark - SSGiftCollectionViewFlowLayout.h文件

#import <UIKit/UIKit.h>

@protocol CustomViewFlowLayoutDelegate <UICollectionViewDelegateFlowLayout>

- (void)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout cellCenteredAtIndexPath:(NSIndexPath *)indexPath page:(int)page;

@end

@interface SSGiftCollectionViewFlowLayout : UICollectionViewFlowLayout

@property (nonatomic, weak) id<CustomViewFlowLayoutDelegate> delegate;

@end

#pragma mark - SSGiftCollectionViewFlowLayout.m文件

@implementation SSGiftCollectionViewFlowLayout

- (void)prepareLayout{

[super prepareLayout];

}

- (id)init {

if (self = [super init]) {

self.scrollDirection = UICollectionViewScrollDirectionHorizontal;

self.minimumInteritemSpacing = 0.0f;

self.sectionInset = UIEdgeInsetsZero;

self.itemSize = CGSizeMake(100.f ,100.f);

self.minimumLineSpacing = 0;

}

return self;

}

- (BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds {

return YES;

}

- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect {

NSArray *attributes = [super layoutAttributesForElementsInRect:rect];

CGRect visibleRect;

visibleRect.origin = self.collectionView.contentOffset;

visibleRect.size = self.collectionView.bounds.size;

for (UICollectionViewLayoutAttributes *attribute in attributes) {

if (CGRectIntersectsRect(attribute.frame, rect)) {

if (visibleRect.origin.x == 0) {

[self.delegate collectionView:self.collectionView layout:self cellCenteredAtIndexPath:attribute.indexPath page:0];

}else{

// 除法取整取余数

div_t x = div(visibleRect.origin.x,visibleRect.size.width);

if (x.quot > 0 && x.rem > 0) {

[self.delegate collectionView:self.collectionView layout:self cellCenteredAtIndexPath:attribute.indexPath page:x.quot + 1];

}

if (x.quot > 0 && x.rem == 0) {

[self.delegate collectionView:self.collectionView layout:self cellCenteredAtIndexPath:attribute.indexPath page:x.quot];

}

return attributes;

}

#pragma mark - CollectionView创建的主要代码

- (UICollectionView *)aCollectionView{

if (_aCollectionView != nil) {

return _aCollectionView;

}

SSGiftCollectionViewFlowLayout *viewFlowLayout = [[SSGiftCollectionViewFlowLayout alloc] init];

viewFlowLayout.delegate = self;

_aCollectionView = [[UICollectionView alloc] initWithFrame:CGRectZero collectionViewLayout:viewFlowLayout];

_aCollectionView.showsHorizontalScrollIndicator = FALSE; // 去掉滚动条

_aCollectionView.alwaysBounceHorizontal = YES;

_aCollectionView.pagingEnabled = YES;

_aCollectionView.scrollEnabled = YES;

_aCollectionView.delegate = self;

_aCollectionView.dataSource = self;

[_aCollectionView registerClass:[CustomCollectionViewCell class] forCellWithReuseIdentifier:identifier];

return _aCollectionView;

}

#pragma mark - 实现CustomViewFlowLayoutDelegate

- (void)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout cellCenteredAtIndexPath:(NSIndexPath *)indexPath page:(int)page{

self.pageControl.currentPage = page; // 分页控制器当前显示的页数

}

效果如下：

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