iOS - anchor view to the top of the screen, behind status bar

Question

I've a CollectionViewController with the default status bar and all it's embedded in a NavigationController.

I'm trying to reproduce an effect in which I have a View anchored to the top of the screen, since my navController is fully transparent and my status bar is also transparent, but somehow when I anchor my view to the topAnchor it stays clipped to the NavigationController bottomAnchor, because it 'thinks' the top of the screen is the navController's bottom.

I managed to bypass this simply after anchoring the view to the top, I gave it a negative topPadding and it now is where I desired it to be.

I know there's a way to extend the layout to the top screen but I can't figure it out.

Can you give me an hint?

I'm trying this:

I'm getting this:

The white space is the status bar height + NavigationController height

Thanks

Answer 1

Well, this pins my UIImageView to the Top of the screen... underneath the nav and status bars. Shouldn't be any different with a collection view:

NSLayoutConstraint *top = [NSLayoutConstraint
                           constraintWithItem:imageView
                           attribute:NSLayoutAttributeTop
                           relatedBy:NSLayoutRelationEqual
                           toItem:self.view
                           attribute:NSLayoutAttributeTop
                           multiplier:1
                           constant:0];

Edit: Sorry, was working in an Obj-C project... here it is in Swift:

    let img = UIImage(named: "Man")
    let imageView = UIImageView(image: img)
    imageView.translatesAutoresizingMaskIntoConstraints = false

    self.view.addSubview(imageView)

    imageView.widthAnchor.constraint(equalToConstant: 200.0).isActive = true
    imageView.heightAnchor.constraint(equalToConstant: 200.0).isActive = true

    imageView.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true

    imageView.topAnchor.constraint(equalTo: self.view.topAnchor).isActive = true

and... here it is with a collection view also (kinda hard to tell with a plain screen-cap):

    self.view.backgroundColor = .white

    let img = UIImage(named: "Man")
    let imageView = UIImageView(image: img)
    imageView.translatesAutoresizingMaskIntoConstraints = false

    self.view.addSubview(imageView)

    imageView.widthAnchor.constraint(equalToConstant: 200.0).isActive = true
    imageView.heightAnchor.constraint(equalToConstant: 200.0).isActive = true

    imageView.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true

    imageView.topAnchor.constraint(equalTo: self.view.topAnchor).isActive = true

    let layout = UICollectionViewFlowLayout()
    let cv = UICollectionView(frame: CGRect.zero, collectionViewLayout: layout)
    cv.backgroundColor = .clear

    cv.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "defaultCell")
    cv.dataSource = self

    cv.translatesAutoresizingMaskIntoConstraints = false
    self.view.addSubview(cv)

    cv.widthAnchor.constraint(equalTo: self.view.widthAnchor, multiplier: 0.9).isActive = true
    cv.heightAnchor.constraint(equalToConstant: 300.0).isActive = true

    cv.centerXAnchor.constraint(equalTo: self.view.centerXAnchor).isActive = true

    cv.topAnchor.constraint(equalTo: self.view.topAnchor).isActive = true