支持靠左，居中，靠右，等间距对齐。
靠左等间距.png
居中等间距.png
靠右等间距.png
#importtypedef NS_ENUM(NSInteger,AlignType){ AlignWithLeft, AlignWithCenter, AlignWithRight};@interface EqualSpaceFlowLayoutEvolve : UICollectionViewFlowLayout//两个Cell之间的距离@property (nonatomic,assign)CGFloat betweenOfCell;//cell对齐方式@property (nonatomic,assign)AlignType cellType;-(instancetype)initWthType : (AlignType)cellType;@end
#import "EqualSpaceFlowLayoutEvolve.h"@interface EqualSpaceFlowLayoutEvolve(){ //在居中对齐的时候需要知道这行所有cell的宽度总和 CGFloat _sumWidth ;}@end@implementation EqualSpaceFlowLayoutEvolve-(instancetype)init{ self = [super init]; if (self){ self.scrollDirection = UICollectionViewScrollDirectionVertical; self.minimumLineSpacing = 5; self.minimumInteritemSpacing = 5; self.sectionInset = UIEdgeInsetsMake(5, 5, 5, 5); _betweenOfCell = 5.0; _cellType = AlignWithLeft; } return self;}-(instancetype)initWthType:(AlignType)cellType{ self = [super init]; if (self){ self.scrollDirection = UICollectionViewScrollDirectionVertical; self.minimumLineSpacing = 5; self.minimumInteritemSpacing = 5; self.sectionInset = UIEdgeInsetsMake(5, 5, 5, 5); _betweenOfCell = 5.0; _cellType = cellType; } return self;}-(void)setBetweenOfCell:(CGFloat)betweenOfCell{ _betweenOfCell = betweenOfCell; self.minimumInteritemSpacing = betweenOfCell;}- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect { NSArray * layoutAttributes_t = [super layoutAttributesForElementsInRect:rect]; NSArray * layoutAttributes = [[NSArray alloc]initWithArray:layoutAttributes_t copyItems:YES]; //用来临时存放一行的Cell数组 NSMutableArray * layoutAttributesTemp = [[NSMutableArray alloc]init]; for (NSUInteger index = 0; index < layoutAttributes.count ; index++) { UICollectionViewLayoutAttributes *currentAttr = layoutAttributes[index]; // 当前cell的位置信息 UICollectionViewLayoutAttributes *previousAttr = index == 0 ? nil : layoutAttributes[index-1]; // 上一个cell 的位置信 UICollectionViewLayoutAttributes *nextAttr = index + 1 == layoutAttributes.count ? nil : layoutAttributes[index+1];//下一个cell 位置信息 //加入临时数组 [layoutAttributesTemp addObject:currentAttr]; _sumWidth += currentAttr.frame.size.width; CGFloat previousY = previousAttr == nil ? 0 : CGRectGetMaxY(previousAttr.frame); CGFloat currentY = CGRectGetMaxY(currentAttr.frame); CGFloat nextY = nextAttr == nil ? 0 : CGRectGetMaxY(nextAttr.frame); //如果当前cell是单独一行 if (currentY != previousY && currentY != nextY){ if ([currentAttr.representedElementKind isEqualToString:UICollectionElementKindSectionHeader]) { [layoutAttributesTemp removeAllObjects]; _sumWidth = 0.0; }else if ([currentAttr.representedElementKind isEqualToString:UICollectionElementKindSectionFooter]){ [layoutAttributesTemp removeAllObjects]; _sumWidth = 0.0; }else{ [self setCellFrameWith:layoutAttributesTemp]; } } //如果下一个不cell在本行，则开始调整Frame位置 else if( currentY != nextY) { [self setCellFrameWith:layoutAttributesTemp]; } } return layoutAttributes;}-(void)setCellFrameWith:(NSMutableArray*)layoutAttributes{ CGFloat nowWidth = 0.0; switch (_cellType) { case AlignWithLeft: nowWidth = self.sectionInset.left; for (UICollectionViewLayoutAttributes * attributes in layoutAttributes) { CGRect nowFrame = attributes.frame; nowFrame.origin.x = nowWidth; attributes.frame = nowFrame; nowWidth += nowFrame.size.width + self.betweenOfCell; } _sumWidth = 0.0; [layoutAttributes removeAllObjects]; break; case AlignWithCenter: nowWidth = (self.collectionView.frame.size.width - _sumWidth - (layoutAttributes.count * _betweenOfCell)) / 2; for (UICollectionViewLayoutAttributes * attributes in layoutAttributes) { CGRect nowFrame = attributes.frame; nowFrame.origin.x = nowWidth; attributes.frame = nowFrame; nowWidth += nowFrame.size.width + self.betweenOfCell; } _sumWidth = 0.0; [layoutAttributes removeAllObjects]; break; case AlignWithRight: nowWidth = self.collectionView.frame.size.width - self.sectionInset.right; for (NSInteger index = layoutAttributes.count - 1 ; index >= 0 ; index-- ) { UICollectionViewLayoutAttributes * attributes = layoutAttributes[index]; CGRect nowFrame = attributes.frame; nowFrame.origin.x = nowWidth - nowFrame.size.width; attributes.frame = nowFrame; nowWidth = nowWidth - nowFrame.size.width - _betweenOfCell; } _sumWidth = 0.0; [layoutAttributes removeAllObjects]; break; }}@end