custom collection view

#import "CategoryCollectionViewLayout2.h"

static NSString * const BHPhotoAlbumLayoutPhotoCellKind = @"Cell";

CGFloat spacingX, spacingY;

@implementation CategoryCollectionViewLayout2

#pragma mark - Lifecycle

- (id)init
{
    self = [super init];
    if (self) {
        [self setup];
    }

    return self;
}

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

    return self;
}

- (void)setup
{
    self.itemInsets = UIEdgeInsetsMake(2.0f, 2.0f, 0.0f, 0.0f);

    if ( UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad ) {
        self.itemSize = CGSizeMake(160.0f, 160.0f);
    } else {
        self.itemSize = CGSizeMake(70.0f, 70.0f);
    }

    self.interItemSpacingY = 2.0f;

   UIInterfaceOrientation iOrientation = [UIApplication sharedApplication].statusBarOrientation;

    if(iOrientation == 1)
    {
        self.numberOfColumns = 3;
        self.numberOfRows = 4;
    }
    else{
        self.numberOfColumns = 5;
        self.numberOfRows = 3;
    }

}


#pragma mark - Layout

- (void)prepareLayout
{
    NSMutableDictionary *newLayoutInfo = [NSMutableDictionary dictionary];
    NSMutableDictionary *cellLayoutInfo = [NSMutableDictionary dictionary];

    NSInteger sectionCount = [self.collectionView numberOfSections];
    NSIndexPath *indexPath = [NSIndexPath indexPathForItem:0 inSection:0];

    for (NSInteger section = 0; section < sectionCount; section++) {
        NSInteger itemCount = [self.collectionView numberOfItemsInSection:section];

        for (NSInteger item = 0; item < itemCount; item++) {
            indexPath = [NSIndexPath indexPathForItem:item inSection:section];

            UICollectionViewLayoutAttributes *itemAttributes =
            [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];
            itemAttributes.frame = [self frameForAlbumPhotoAtIndexPath:indexPath];

            cellLayoutInfo[indexPath] = itemAttributes;
        }
    }

    newLayoutInfo[BHPhotoAlbumLayoutPhotoCellKind] = cellLayoutInfo;

    self.layoutInfo = newLayoutInfo;

}

#pragma mark - Private

- (CGRect)frameForAlbumPhotoAtIndexPath:(NSIndexPath *)indexPath
{
    NSInteger row = indexPath.row / self.numberOfColumns;
    NSInteger column = indexPath.row % self.numberOfColumns;

    if ( UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad ) {
        /*spacingX = self.collectionView.bounds.size.width -
        self.itemInsets.left -
        self.itemInsets.right -
        (self.numberOfColumns * self.itemSize.width);

        spacingY = self.collectionView.bounds.size.height - self.itemInsets.top - self.itemInsets.bottom - (self.numberOfRows * self.itemSize.height);*/

        spacingX = 7.0f;

        spacingY = 7.0f;

    } else {

        spacingX = 2.0f;

        spacingY = 2.0f;

    }



    //CGFloat spacingY = 10.0f;

    if(self.numberOfRows > 1) spacingY = spacingY / (self.numberOfRows - 1);

    //CGFloat spacingX = 0.0f;

    if (self.numberOfColumns > 1) spacingX = spacingX / (self.numberOfColumns - 1);

    CGFloat originX = floorf(self.itemInsets.left + (self.itemSize.width + spacingX) * column);

    CGFloat originY = floor(self.itemInsets.top +
                            (self.itemSize.height + spacingY) * row);

    //CGFloat originY = floor((self.itemSize.height + spacingY) * row);

    return CGRectMake(originX, originY, self.itemSize.width, self.itemSize.height);


}

- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
{

    NSMutableArray *allAttributes = [NSMutableArray arrayWithCapacity:self.layoutInfo.count];

    [self.layoutInfo enumerateKeysAndObjectsUsingBlock:^(NSString *elementIdentifier,
                                                         NSDictionary *elementsInfo,
                                                         BOOL *stop) {
        [elementsInfo enumerateKeysAndObjectsUsingBlock:^(NSIndexPath *indexPath,
                                                          UICollectionViewLayoutAttributes *attributes,
                                                          BOOL *innerStop) {
            if (CGRectIntersectsRect(rect, attributes.frame)) {
                [allAttributes addObject:attributes];
            }
        }];
    }];

    return allAttributes;
}

- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath
{
    return self.layoutInfo[BHPhotoAlbumLayoutPhotoCellKind][indexPath];
}

- (CGSize)collectionViewContentSize
{
    NSInteger rowCount = [self.collectionView numberOfSections] / self.numberOfColumns;
    // make sure we count another row if one is only partially filled
    if ([self.collectionView numberOfSections] % self.numberOfColumns) rowCount++;

    CGFloat height = self.itemInsets.top +
    rowCount * self.itemSize.height + (rowCount - 1) * self.interItemSpacingY +
    self.itemInsets.bottom;

    return CGSizeMake(self.collectionView.bounds.size.width, height);
}

@end