UICollectionView Cell Overlap

Question

Ich habe eine horizontale UICollectionView. Ich möchte, dass die Zellen sich um eine bestimmte Anzahl von 60 Pixeln überlappen, so dass die zweiten Zellen die erste um 60 Pixel überlappen und die dritte die zweite um den gleichen Betrag und so weiter überlappt.

Ich habe versucht, UICollectionViewFlowLayout sub-Klasse. Aber ich kann die UICollectionviewCell nicht übereinander legen.

Answer 1

mit diesem Tutorial starten: https://web-beta.archive.org/web/20151116053251/http://blog.tobiaswiedenmann.com/post/35135290759/stacklayout

ich die stacklayout speziell für eine horizontale UICollectionView

UICollectionViewStackLayout.h

#import <UIKit/UIKit.h> 

@interface UICollectionViewStackLayout : UICollectionViewFlowLayout 

#define STACK_OVERLAP 60 //this corresponds to 60 points which is probably what you want, not pixels 
#define ITEM_SIZE CGSizeMake(190,210) 

@end 

UICollectionViewStackLayout.m

#import "UICollectionViewStackLayout.h" 

@implementation UICollectionViewStackLayout 

-(id)init{ 

    self = [super init]; 

    if (self) { 
     [self commonInit]; 
    } 

    return self; 
} 

-(id)initWithCoder:(NSCoder *)aDecoder 
{ 
    if (self = [super init]) { 
     [self commonInit]; 
    } 

    return self; 
} 

-(void)commonInit 
{ 
    self.itemSize = ITEM_SIZE; 

    //set minimum layout requirements 
    self.scrollDirection = UICollectionViewScrollDirectionHorizontal; 
    self.minimumInteritemSpacing = 0; 
} 

-(CGSize)collectionViewContentSize 
{ 
    NSInteger xSize = [self.collectionView numberOfItemsInSection:0] 
    * self.itemSize.width; 
    NSInteger ySize = [self.collectionView numberOfSections] 
    * (self.itemSize.height); 

    CGSize contentSize = CGSizeMake(xSize, ySize); 

    if (self.collectionView.bounds.size.width > contentSize.width) 
     contentSize.width = self.collectionView.bounds.size.width; 

    if (self.collectionView.bounds.size.height > contentSize.height) 
     contentSize.height = self.collectionView.bounds.size.height; 

    return contentSize; 
} 

-(NSArray*)layoutAttributesForElementsInRect:(CGRect)rect 
{ 
    NSArray* attributesArray = [super layoutAttributesForElementsInRect:rect]; 
    int numberOfItems = [self.collectionView numberOfItemsInSection:0]; 

    for (UICollectionViewLayoutAttributes *attributes in attributesArray) { 
     CGFloat xPosition = attributes.center.x; 
     CGFloat yPosition = attributes.center.y; 

     if (attributes.indexPath.row == 0) { 
      attributes.zIndex = INT_MAX; // Put the first cell on top of the stack 
     } else { 
      xPosition -= STACK_OVERLAP * attributes.indexPath.row; 
      attributes.zIndex = numberOfItems - attributes.indexPath.row; //Other cells below the first one 
     } 

     attributes.center = CGPointMake(xPosition, yPosition); 
    } 

    return attributesArray; 
} 

- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)path { 
    UICollectionViewLayoutAttributes* attributes = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:path]; 
    return attributes; 
} 

@end 

Answer 2

geändert habe ich mdewitt des ein swer, verwandelte es in swift 3 und ich arbeite super! Für alle Interessierten:

class CollectionViewOverlappingLayout: UICollectionViewFlowLayout { 

var overlap: CGFloat = 30 

required init?(coder aDecoder: NSCoder) { 
    super.init(coder: aDecoder) 
    self.scrollDirection = .horizontal 
    self.minimumInteritemSpacing = 0 
} 

override var collectionViewContentSize: CGSize{ 
    let xSize = CGFloat(self.collectionView!.numberOfItems(inSection: 0)) * self.itemSize.width 
    let ySize = CGFloat(self.collectionView!.numberOfSections) * self.itemSize.height 

    var contentSize = CGSize(width: xSize, height: ySize) 

    if self.collectionView!.bounds.size.width > contentSize.width { 
     contentSize.width = self.collectionView!.bounds.size.width 
    } 

    if self.collectionView!.bounds.size.height > contentSize.height { 
     contentSize.height = self.collectionView!.bounds.size.height 
    } 

    return contentSize 
} 

override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? { 

    let attributesArray = super.layoutAttributesForElements(in: rect) 
    let numberOfItems = self.collectionView!.numberOfItems(inSection: 0) 

    for attributes in attributesArray! { 
     var xPosition = attributes.center.x 
     let yPosition = attributes.center.y 

     if attributes.indexPath.row == 0 { 
      attributes.zIndex = Int(INT_MAX) // Put the first cell on top of the stack 
     } else { 
      xPosition -= self.overlap * CGFloat(attributes.indexPath.row) 
      attributes.zIndex = numberOfItems - attributes.indexPath.row //Other cells below the first one 
     } 

     attributes.center = CGPoint(x: xPosition, y: yPosition) 
    } 

    return attributesArray 
} 

override func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? { 
    return UICollectionViewLayoutAttributes(forCellWith: indexPath) 
} 
}