Collection view cells and headings which, together, give a nice grid with light gray borders between each element.

FDRCollectionViewCell.h

//
//  FDRCollectionViewCell.h
//  
//
//  Created by Brent Royal-Gordon on 7/10/13.
//
//

#import <UIKit/UIKit.h>

@interface FDRCollectionViewCell : UICollectionViewCell

@end

FDRCollectionViewCell.m

//
//  FDRCollectionViewCell.m
//  
//
//  Created by Brent Royal-Gordon on 7/10/13.
//
//

#import "FDRCollectionViewCell.h"
#import "FDRCollectionViewFlowLayout.h"

@interface FDRCollectionViewCellBackgroundView : UIView

@property (assign, nonatomic) BOOL rightBorderHidden;
@property (assign, nonatomic) BOOL bottomBorderHidden;

@end

@implementation FDRCollectionViewCell

- (void)awakeFromNib {
    [super awakeFromNib];
    
    self.backgroundView = [FDRCollectionViewCellBackgroundView new];
    self.backgroundView.backgroundColor = self.backgroundColor;
    self.backgroundView.opaque = self.opaque;
    
    self.selectedBackgroundView = [UIView new];
    self.selectedBackgroundView.backgroundColor = [UIColor colorWithWhite:0.0 alpha:0.03];
    self.selectedBackgroundView.opaque = NO;
}

- (void)setBackgroundColor:(UIColor *)backgroundColor {
    super.backgroundColor = backgroundColor;
    
    self.backgroundView.backgroundColor = backgroundColor;
}

- (void)setOpaque:(BOOL)opaque {
    super.opaque = opaque;
    
    self.backgroundView.opaque = opaque;
}

- (void)applyLayoutAttributes:(FDRCollectionViewLayoutAttributes *)layoutAttributes {
    [super applyLayoutAttributes:layoutAttributes];
    
    FDRCollectionViewCellBackgroundView * background = (id)self.backgroundView;
    background.bottomBorderHidden = layoutAttributes.inLastRowOfSection && !layoutAttributes.inLastSection;
    background.rightBorderHidden = layoutAttributes.againstRightEdge;
}

@end

@implementation FDRCollectionViewCellBackgroundView

- (void)setBottomBorderHidden:(BOOL)bottomBorderHidden {
    _bottomBorderHidden = bottomBorderHidden;
    [self setNeedsDisplay];
}

- (void)setRightBorderHidden:(BOOL)rightBorderHidden {
    _rightBorderHidden = rightBorderHidden;
    [self setNeedsDisplay];
}

- (void)drawRect:(CGRect)rect {
    [super drawRect:rect];
    
    [[UIColor colorWithWhite:0.74 alpha:1.0] set];
    
    CGFloat thickness = 1 / self.contentScaleFactor;
    
    if(!self.rightBorderHidden) {
        UIRectFill(CGRectMake(CGRectGetMaxX(self.bounds) - thickness, 0, thickness, CGRectGetHeight(self.bounds)));
    }
    if(!self.bottomBorderHidden) {
        UIRectFill(CGRectMake(0, CGRectGetMaxY(self.bounds) - thickness, CGRectGetWidth(self.bounds), thickness));
    }
}

@end

FDRCollectionViewFlowLayout.h

//
//  FDRCollectionViewFlowLayout.h
//  Feeder
//
//  Created by Brent Royal-Gordon on 7/11/13.
//  Copyright (c) 2013 Architechies. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface FDRCollectionViewFlowLayout : UICollectionViewFlowLayout

@end

@interface FDRCollectionViewLayoutAttributes : UICollectionViewLayoutAttributes

@property (assign, nonatomic, getter = isInLastRowOfSection) BOOL inLastRowOfSection;
@property (assign, nonatomic, getter = isInLastSection) BOOL inLastSection;

@property (assign, nonatomic, getter = isAgainstRightEdge) BOOL againstRightEdge;

@end

FDRCollectionViewFlowLayout.m

//
//  FDRCollectionViewFlowLayout.m
//  Feeder
//
//  Created by Brent Royal-Gordon on 7/11/13.
//  Copyright (c) 2013 Architechies. All rights reserved.
//

#import "FDRCollectionViewFlowLayout.h"

@implementation FDRCollectionViewFlowLayout

+ (Class)layoutAttributesClass {
    return [FDRCollectionViewLayoutAttributes class];
}

- (void)intuitSectioningAttributes:(FDRCollectionViewLayoutAttributes*)attributes {
    NSIndexPath * lastIndexPath = [NSIndexPath indexPathForItem:[self.collectionView numberOfItemsInSection:attributes.indexPath.section] - 1 inSection:attributes.indexPath.section];
    attributes.inLastRowOfSection = [lastIndexPath isEqual:attributes.indexPath] || attributes.center.y == [super layoutAttributesForItemAtIndexPath:lastIndexPath].center.y;
    
    attributes.inLastSection = attributes.indexPath.section == self.collectionView.numberOfSections - 1;
    
    attributes.againstRightEdge = CGRectGetMaxX(attributes.frame) == CGRectGetMaxX(self.collectionView.bounds);
}

- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath {
    FDRCollectionViewLayoutAttributes * attributes = (id)[super layoutAttributesForItemAtIndexPath:indexPath];
    
    [self intuitSectioningAttributes:attributes];
    
    return attributes;
}

- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect {
    NSArray * attributesArray = [super layoutAttributesForElementsInRect:rect];
    for(FDRCollectionViewLayoutAttributes * attrs in attributesArray) {
        [self intuitSectioningAttributes:attrs];
    }
    return attributesArray;
}

@end

@implementation FDRCollectionViewLayoutAttributes

- (id)copyWithZone:(NSZone *)zone {
    FDRCollectionViewLayoutAttributes * copy = [super copyWithZone:zone];
    
    copy.inLastRowOfSection = self.inLastRowOfSection;
    copy.inLastSection = self.inLastSection;
    
    copy.againstRightEdge = self.againstRightEdge;
    
    return copy;
}

@end

FDRSectionHeaderView.h

//
//  FDRSectionHeaderView.h
//  Feeder
//
//  Created by Brent Royal-Gordon on 7/11/13.
//  Copyright (c) 2013 Architechies. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface FDRSectionHeaderView : UICollectionReusableView

@property (weak, nonatomic) IBOutlet UILabel * titleLabel;

@end

FDRSectionHeaderView.m

//
//  FDRSectionHeaderView.m
//  Feeder
//
//  Created by Brent Royal-Gordon on 7/11/13.
//  Copyright (c) 2013 Architechies. All rights reserved.
//

#import "FDRSectionHeaderView.h"

@implementation FDRSectionHeaderView

- (void)drawRect:(CGRect)rect {
    [super drawRect:rect];
    
    [[UIColor colorWithWhite:0.74 alpha:1.0] set];
    
    CGFloat thickness = 1 / self.contentScaleFactor;
    
    UIRectFill(CGRectMake(0, 0, CGRectGetWidth(self.bounds), thickness));
    UIRectFill(CGRectMake(0, CGRectGetMaxY(self.bounds) - thickness, CGRectGetWidth(self.bounds), thickness));
}

@end

I am using different cell sizes for Portrait and Landscape orientations and calling
[self.collectionView performBatchUpdates:nil completion:nil] on didRotateFromInterfaceOrientation
But it seems the drawRect is not called and the borders remain the same.
The borders should also resize accordingly. How can it be achieved?

Hi am two months of experience in ios. i don't know how to use those classes. so please explain briefly