Custom View in Cocoa can't draw after setting AutoLayout Constraints - swift

Question

On a MacOS Project.
I'm trying to draw a line under a text field (so that by making the text field transparent I can create a "please fill in the blank" style of view that asks the user to input the data). I created a simple subclass of NSView called lineDrawer just to draw the line, then I tried to add an instance of a lineDrawer as a subview to the view where I let the user enter his name. The line should be drawn right below the transparent text field. The text field is an IBOutlet of the view and already in correct position, and I want the line to have the exact same frame as the text field, so that if I draw a path from the lineDrawer's (minX, minY)to (maxX, minY), the path is exactly below the transparent text field.
I can't make it work because after I set
lineView.translatesAutoresizingMaskIntoConstraints = false
and added my own constraints, the custom view wouldn't draw. I think it has something to do with me not giving the program enough information about where exactly to draw the view, but I can't figure out what's lacking here. BTW, if I don't set the constraints, it would just draw the view at its frame's place. If I set the constraints, nothing shows.
The NickName: NSViewController
override func viewDidLoad() {
super.viewDidLoad()
// Do view setup here.
greetingLine.font = .labelFont(ofSize: 50)
nameField.font = .labelFont(ofSize: 50)
nameField.isBezeled = false
let lineView = lineDrawer.init()
lineView.setFrameSize(nameField.frame.size)
self.view.addSubview(lineView)
lineView.translatesAutoresizingMaskIntoConstraints = false
let lineConstraintX = NSLayoutConstraint.init(item: lineView, attribute: .centerX, relatedBy: .equal, toItem: self.view, attribute: .centerX, multiplier: 1, constant: 0)
let lineConstraintY = NSLayoutConstraint.init(item: lineView, attribute: .centerY, relatedBy: .equal, toItem: self.view, attribute: .centerY, multiplier: 1.3, constant: 0)
self.view.addConstraints([lineConstraintY, lineConstraintX])
}
#IBOutlet weak var nameField: NSTextField!
#IBOutlet weak var greetingLine: NSTextField!
and the lineDrawer: NSView:
override func draw(_ dirtyRect: NSRect) {
super.draw(dirtyRect)
// Drawing code here.
let context = NSGraphicsContext.current?.cgContext
context!.beginPath()
context!.move(to: CGPoint(x: self.bounds.minX, y: self.bounds.minY))
let endPoint = CGPoint.init(x: self.bounds.maxX, y: self.bounds.minY)
context!.addLine(to: endPoint)
context!.move(to: CGPoint(x: 0, y: 0))
context!.addLine(to: CGPoint(x: 10, y: 10))
let loadedColor = ColorGetter.getCurrentThemeColor()
context!.setStrokeColor(loadedColor.cgColor)
context!.setLineWidth(5)
context!.strokePath()
print("drawing")
}
Thanks very much in advance to anyone who would offer help on this!

Answer 1

Can you, please, add behind your layout constraint the variable isActive and set it to be true. Then ist should work.
So, the code you have:
let lineConstraintX = NSLayoutConstraint.init(item: lineView, attribute: .centerX, relatedBy: .equal, toItem: self.view, attribute: .centerX, multiplier: 1, constant: 0)
let lineConstraintY = NSLayoutConstraint.init(item: lineView, attribute: .centerY, relatedBy: .equal, toItem: self.view, attribute: .centerY, multiplier: 1.3, constant: 0)
Must be changed in:
NSLayoutConstraint.init(item: lineView, attribute: .centerX, relatedBy: .equal, toItem: self.view, attribute: .centerX, multiplier: 1, constant: 0).isActive = true
NSLayoutConstraint.init(item: lineView, attribute: .centerY, relatedBy: .equal, toItem: self.view, attribute: .centerY, multiplier: 1.3, constant: 0).isActive = true
Then the auto layout constraint is activated and works. Currently, you did set the auto layout constraint, but you didn't activate it.

Answer 2

Answering my own question:
I added 2 constraints to the custom view's width and height by
NSLayoutConstraint.init(item: lineView, attribute: .width, relatedBy: .equal, toItem: self.nameField, attribute: .width, multiplier: 1, constant: 0).isActive = true
NSLayoutConstraint.init(item: lineView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: 100).isActive = true
I think by making
lineView.translatesAutoresizingMaskIntoConstraints = false
I was removing the program's knowledge about both the custom view's position and size, and so I had to re-specify them both manually?
Weird that the program doesn't imply what the size of the custom view should be from its frame's size, which was set.