Add Constraint to navigationBar Programmatically Swift - ios

Question

I'm trying to add constraint to navigation bar, I have UIImageView, which has width, height and is centered horizontally, I want to add vertical space between UIImage and navigationBar to 0, I'm trying this for like 1 hour and couldn't figure out how, i tried adding constraint to UIView, and added constant of navbarHeight + statusBarHeight, and it worked, but I want to make relationship between imageview and navbar
let verticalSpace = NSLayoutConstraint(item: image, attribute: .Top, relatedBy: .Equal, toItem: self.view, attribute: .Top, multiplier: 1, constant: 0)
view.addConstraint(verticalSpace) // this works

Answer 1

try with topLayoutGuide
let verticalSpace = NSLayoutConstraint(item: image,
attribute: .Top,
relatedBy: .Equal,
toItem: self.topLayoutGuide,
attribute: .Bottom,
multiplier: 1, constant: 0)
The above constraint explanation:
simply its called: vertical space between image.Top & self.topLayoutGuide.Bottom = 0
that means Top constraint of image view attached with a Bottom attribute of topLayoutGuide with constant 0.
You can use anchors as well to make this possible for iOS 10+
if #available(iOS 11.0, *) {
image.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
} else {
image.topAnchor.constraint(equalTo: topLayoutGuide.bottomAnchor).isActive = true
}

Answer 2

llkenny's answer for iOS 11.0+ :
image.topAnchor.constraint(equalTo:
view.safeAreaLayoutGuide.topAnchor).isActive = true

Answer 3

With anchors:
image.topAnchor.constraint(equalTo: topLayoutGuide.bottomAnchor).isActive = true

Answer 4

In storyboard. Two constraints:
The first:
The second:
Result:

Answer 5

code:
func mainCollectionViewConstraint() {
NSLayoutConstraint.activate([
mainCollectionView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 10),
mainCollectionView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
mainCollectionView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
mainCollectionView.trailingAnchor.constraint(equalTo: view.trailingAnchor)
])
}