How to make UICollectionheader transparent while scrolling up?

Question

Please help me to make the UICollectionview header transparent while we scroll the collection view up. I have used UICollectionReusableView and set it background as clear color, but no use. WHILE MOVING UP THE HEADER ( SHOWN IN BLACK COLOR) SHOULD BECOME TRANSPARENT.... THAT IS THE ORANGE BACKGROUND SHOULD BE SLIGHTLY VISIBLE....

Answer 1

Not enough info, but I'll try to answer

First, you should keep pointer to your header view constantly

@property UICollectionReusableView *collectionHeaderView;

Create it once in viewDidLoad and than use it as a header view (whatever that means) in your collection view.

Next, to change collor on dragging up you'll need delegate method. UICollectionViewDelegate conforms to UIScrollViewDelegate, so you can use its method

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{ 
     CGPoint translation = [scrollView.panGestureRecognizer translationInView:scrollView.superview];

     if(translation.y > 0)
     {
        //dragging down
        collectionHeaderView.backgroundColor = <#Whatever you need#>;
     } else
     {
         // dragging up
         collectionHeaderView.backgroundColor = [UIColor clearColor];
     }
 }

Special thanks to @mvielbut for answer

Update

According to comments to mvielbut's answer, this method is not always reliable, so you can use another approach (you'll need to check offset.y instead).