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Collection View, with custom layouts, cells do not work properly when scrolling

I am trying to create a custom broken layout using a UICollectionView. When I launch my application, it performs its best in the simulator.

But at the moment when I look at the view and return it all changes to the cell frame, and the cells overlap, leaving spaces at random.

I can not solve this problem in the last 2 days. Here is the code from my own layout class.

-(void)prepareLayout{ [self createCellSizeArray];//cellSizeArray holds cell sizes for all the cells(calculated statically) [self createAttributeArrayOfAll];//attributeArrayOfAll holds attributes for all the cells and also calculates their frames using cellSizeArray } -(CGSize)collectionViewContentSize{ return CGSizeMake(768, 1500);//The size is static to check for scrolling, is this creating problems? } -(UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath{ UICollectionViewLayoutAttributes * layoutAttributes = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath]; return layoutAttributes; } -(NSArray *)layoutAttributesForElementsInRect:(CGRect)rect{ NSMutableArray *attArray =[NSMutableArray array]; for (NSInteger i =0; i< attributeArrayOfAll.count; i++) { UICollectionViewLayoutAttributes * attribute = (UICollectionViewLayoutAttributes*)[attributeArrayOfAll objectAtIndex:i]; if(CGRectIntersectsRect(rect, attribute.frame)){ [attArray addObject:attribute]; } } return attArray; } -(BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds{ return YES; }

Please help in advance.

Edit : In my [self createAttributeArrayOfAll]; I have these lines of code

 CGRect frame = CGRectMake(_startNewRowPoint.x, _startNewRowPoint.y, cellSize.width, cellSize.height); UICollectionViewLayoutAttributes * attribute = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:[NSIndexPath indexPathForItem:i inSection:0]]; attribute.alpha = 1.0; attribute.frame = frame; [attributeArrayOfAll addObject:attribute];

So far I've been layoutAttributesForItemAtIndexPath: to see something like this

 -(UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath{ UICollectionViewLayoutAttributes * layoutAttributes = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath]; layoutAttributes.frame = ((UICollectionViewLayoutAttributes*)[attributeArrayOfAll objectAtIndex:indexPath.item]).frame; return layoutAttributes; }

In addition, the layoutAttributesForItemAtIndexPath: method will never be called implicitly. I even tried this:

 -(NSArray *)layoutAttributesForElementsInRect:(CGRect)rect{ NSMutableArray *attArray =[NSMutableArray arrayWithCapacity:attributeArrayOfAll.count]; for (NSInteger i =0; i< attributeArrayOfAll.count; i++) { UICollectionViewLayoutAttributes * attribute = (UICollectionViewLayoutAttributes*)[attributeArrayOfAll objectAtIndex:i]; if(CGRectIntersectsRect(rect, attribute.frame)){ [attArray insertObject:[self layoutAttributesForItemAtIndexPath:[NSIndexPath indexPathForItem:i inSection:0]] atIndex:i]; } } return attArray; }

But still, the result is the same distorted set of cells when scrolling. I worked with 5 cells, the first time it is displayed correctly, when scrolling and then returning to the visible rectangle, it is distorted if I scroll away again and return it to the visible rectangle that it displays correctly. However, when I do this with approximately 400 cells, as soon as I scroll through it, it will never display correctly. Even when the collection is overloaded, the cells are distorted. Please, help.

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2 answers

So, finally, a workaround was made !!! delete each cell with a unique cell id in cellForRow:

 [self.summaryView registerClass:[BFSSummaryViewCell class] forCellWithReuseIdentifier:[NSString stringWithFormat:@"%@%d",CellIdentifier,indexPath.row]]; UICollectionViewCell *collectionCell = [collectionView dequeueReusableCellWithReuseIdentifier:[NSString stringWithFormat:@"%@%d",CellIdentifier,indexPath.row] forIndexPath:indexPath];

These two lines inside cellForRow worked for me, however, when my browsing the collection has about 1000 cells, it significantly increases the size of my application. Let's hope that the apple corrects this error as soon as possible.

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Your layoutAttributesForItemAtIndexPath: method layoutAttributesForItemAtIndexPath: not set any properties of the layoutAttributes object before returning it. It should set frame (or center and size ).

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