Auto fit all UICollectionViewCell from data source to screen without scrolling - ios

Question

I've an array of UIColor's in my data source, what I'm trying to do is to fit all cells' size so they can all be seen on screen without scrolling.
I don't know how to do it, so far I've:
#pragma mark <UICollectionViewDataSource>
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
return 1;
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return self.dataSource.count;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:reuseIdentifier forIndexPath:indexPath];
// Configure the cell
UIColor *cellColor = (UIColor *)self.dataSource[indexPath.row];
cell.backgroundColor = cellColor;
for (UIView *view in cell.contentView.subviews) {
if ([view isKindOfClass:[UIImageView class]]) {
if ([[(UIImageView *)view image] isEqual:[UIImage imageNamed:#"V_BG.png"]]) {
[view removeFromSuperview];
}
}
}
if ([cellColor isEqual:self.existingColor]) {
UIImageView *img = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"V_BG.png"]];
img.frame = CGRectMake(0, 0, 30, 30);
img.center = cell.contentView.center;
img.backgroundColor = [UIColor clearColor];
[cell.contentView addSubview:img];
}
return cell;
}
#pragma mark <UICollectionViewDelegate>
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
[[NSNotificationCenter defaultCenter] postNotificationName:UIColorDidChangeNotification
object:[NSString stringWithFormat:#"%ld", (long)indexPath.row]];
[self.navigationController popViewControllerRetro];
}
#pragma mark Collection view layout things
// Layout: Set cell size
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
CGFloat fixSize = ([UIScreen mainScreen].bounds.size.width / 3) - 2;
return CGSizeMake(fixSize, fixSize);
}
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section
{
return 2;
}
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section
{
return 2;
}
- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section
{
return UIEdgeInsetsMake(0, 0, 0, 0);
}