UIcollectionViewFlowLayout class for changing the scroll direction based on device orientation.

CollectionViewOrientingFlowLayout.m

//
//  CollectionViewOrientingFlowLayout.m
//  iP2
//
//  Created by Lee Probert on 08/03/2013.
//
//

#define ITEM_SIZE 150.0f
#define PADDING 20

#import "CollectionViewOrientingFlowLayout.h"

@interface CollectionViewOrientingFlowLayout (){
    
    UIInterfaceOrientation _orientation;
}

-(void)initLayoutProperties;

@end

@implementation CollectionViewOrientingFlowLayout

-(void)prepareLayout {
    
    [super prepareLayout];
    [self initLayoutProperties];
}

-(void)initLayoutProperties {
    
    _orientation = [[UIApplication sharedApplication] statusBarOrientation];
    
    self.itemSize = CGSizeMake(ITEM_SIZE, ITEM_SIZE);
    self.scrollDirection = UIInterfaceOrientationIsPortrait(_orientation)? UICollectionViewScrollDirectionVertical : UICollectionViewScrollDirectionHorizontal;
    self.minimumLineSpacing = PADDING;
    self.minimumInteritemSpacing = PADDING;
}

@end