This gist helps with placing views inside each other using autolayout constraints

UIView+Embed.swift

public typealias ConstraintsConfiguration = (_ top: NSLayoutConstraint, _ left: NSLayoutConstraint, _ bottom: NSLayoutConstraint, _ right: NSLayoutConstraint) -> Void

extension UIView {
    /**
     Embeds a subview inside the current view and adds constraints to fit the subview in the whole view. An optional constraints configuration closure can be specified to do extra customization for the added constraints, or you can keep a reference for the added constraints in this closure.
     - Parameter subview: The subview that will be added
     - Parameter constraintsConfiguration: The constraint configuration that will be applied to the newly added constraints
     */
    public func addSubviewWithConstraints(_ subview: UIView, constraintsConfiguration: ConstraintsConfiguration? = nil) {
        // Required to disable auto generation of constraints
        subview.translatesAutoresizingMaskIntoConstraints = false
        
        // Create a top, left, bottom and right constraints
        let viewConstraints = [NSLayoutConstraint.Attribute.top,
                               NSLayoutConstraint.Attribute.left,
                               NSLayoutConstraint.Attribute.bottom,
                               NSLayoutConstraint.Attribute.right].map { (attribute) -> NSLayoutConstraint in
                                return NSLayoutConstraint(item: subview, attribute: attribute, relatedBy: .equal, toItem: self, attribute: attribute, multiplier: 1, constant: 0)
        }
        
        // Insert subview in view
        addSubview(subview)
        
        // Apply constraints
        addConstraints(viewConstraints)
        
        // Call closure to configure constraints
        constraintsConfiguration?(viewConstraints[0], viewConstraints[1], viewConstraints[2], viewConstraints[3])
    }
}