CollectionView Cell add 1px boarder become 2px - ios

Question

The designer need my each collectionView Cell have a 1px boarder,Like below:
And my implementation show,seem some border overlap and become 2px，Is there other easy way to get it done? Thanks for help.
Here is the main code:
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
ServiceCategoryCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"ServiceCategoryCollectionViewCell" forIndexPath:indexPath];
cell.entity = _categoryList[indexPath.row];
[cell.contentView addBorderWithWidth:0.5f hexColorString:#"#EFEFF4" cornerRadius:0];
return cell;
}
- (void)setupCollectionView{
UICollectionViewFlowLayout *flowFayout = [[UICollectionViewFlowLayout alloc] init];
flowFayout.scrollDirection = UICollectionViewScrollDirectionVertical;
flowFayout.minimumInteritemSpacing = 0;
flowFayout.minimumLineSpacing = 0;
flowFayout.itemSize = CGSizeMake(self.contentView.keyWindowWidth/4, self.contentView.height);
_categoryCollectionVIew.delegate = self;
_categoryCollectionVIew.dataSource = self;
_categoryCollectionVIew.scrollEnabled = NO;
_categoryCollectionVIew.collectionViewLayout = flowFayout;
[_categoryCollectionVIew registerNib:[UINib nibWithNibName:#"ServiceCategoryCollectionViewCell" bundle:nil] forCellWithReuseIdentifier:#"ServiceCategoryCollectionViewCell"];
}
-(void)addBorderWithWidth:(float)width hexColorString:(NSString *)color cornerRadius:(CGFloat)cornerRadius{
self.layer.borderWidth = width;
self.layer.borderColor = [UIColor colorWithHexString:color alpha:1].CGColor;
self.layer.cornerRadius = cornerRadius;
self.layer.masksToBounds = YES;
}

Answer 1

Solution Of Overlapping CollectionView Cell Border:
add bottom and right side border through CALayer()
Objective c:
CALayer *bottomBorder = [CALayer layer];
bottomBorder.borderColor = [UIColor darkGrayColor].CGColor;
bottomBorder.frame = CGRectMake(0, cell.contentView.frame.height - 1,
cell.contentView.frame.width, 1);
[cell.layer.layer addSublayer:bottomBorder];
CALayer *rightBorder = [CALayer layer];
rightBorder.borderColor = [UIColor darkGrayColor].CGColor;
rightBorder.frame = CGRectMake(cell.contentView.frame.width, 0, 1,
cell.contentView.frame.height);
[cell.layer.layer addSublayer:rightBorder];
Swift :
let rightborder = CALayer()
rightborder.frame = CGRect(x:cell.frame.width - 1,y: 0, width: 1, height: cell.frame.height)
rightborder.backgroundColor = UIColor.darkGray.cgColor;
cell.layer.addSublayer(rightborder)
let bottomborder = CALayer()
bottomborder.frame = CGRect(x: 0, y: cell.frame.height - 1, width: cell.frame.width, height: 1)
bottomborder.backgroundColor = UIColor.darkGray.cgColor;
cell.layer.addSublayer(bottomborder)

Answer 2

I don't know its work but first try open simulator in fullscreen.

Answer 3

This is simulator problem, check you code in device and then compare.