右からスライドインしてくるCollectionViewのアニメーション

- (void)collectionView:(UICollectionView *)collectionView willDisplayCell:(UICollectionViewCell *)cell forItemAtIndexPath:(NSIndexPath *)indexPath {

    CGRect cellRect = cell.frame;
    cell.frame = CGRectMake(self.mCollectionCell * indexPath.row + self.view.frame.size.width, cell.frame.origin.y, cell.frame.size.width, cell.frame.size.height);
    float value = indexPath.row * 0.1;
    [UIView animateWithDuration:1 delay:value options:UIViewAnimationOptionCurveEaseInOut animations:^{
        cell.frame = CGRectMake(cellRect.origin.x + self.view.frame.size.width, cellRect.origin.y, cellRect.size.width, cellRect.size.height);
    } completion:^(BOOL finished) {
        cell.frame = cellRect;
        }];
    }];