一个UICollectionView自定义layout的实现

#import "DraggableCircleLayout.h"
#import "LSCollectionViewLayoutHelper.h"

@interface DraggableCircleLayout()
{
LSCollectionViewLayoutHelper *_layoutHelper;
}
@end

@implementation DraggableCircleLayout

- (LSCollectionViewLayoutHelper *)layoutHelper
{
if(_layoutHelper == nil) {
_layoutHelper = [[LSCollectionViewLayoutHelper alloc] initWithCollectionViewLayout:self];
}
return _layoutHelper;
}

- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
{
return [self.layoutHelper modifiedLayoutAttributesForElements:[super layoutAttributesForElementsInRect:rect]];
}

@end