UICollectionView display 3 items per row

here i did it , i implemented UICollectionViewDelegateFlowLayout on UICollectionView add following method . it work , use it .

- (CGSize)collectionView:(UICollectionView *)collectionView
                  layout:(UICollectionViewLayout *)collectionViewLayout
  sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    CGRect screenRect = [[UIScreen mainScreen] bounds];
    CGFloat screenWidth = screenRect.size.width;
    float cellWidth = screenWidth / 3.0; //Replace the divisor with the column count requirement. Make sure to have it in float.
    CGSize size = CGSizeMake(cellWidth, cellWidth);

    return size;
}

this method work as screen size width divided by 3 .

(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
  CGRect screenRect = [[UIScreen mainScreen] bounds];
  CGFloat screenWidth = screenRect.size.width;
  float cellWidth = screenWidth / 3.2; //Replace the divisor with the column count requirement. Make sure to have it in float.
  CGFloat screenHeight = screenRect.size.height;
  float cellHeight = screenHeight/3.0;


  CGSize size = CGSizeMake(cellWidth, cellHeight);


  return size;
}

Apply the below code too-(viewWillTransitionToSize)

(void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {
  [self.collectionView/*(that's my collection view name)*/ reloadData];
}

This Code will help to get the same no. of cells in portrait as well as in landscape mode also. I have applied above code to get 3 cells in portrait as well as 3 cells in landscape mode.