Setting 2 label in header programatically - not label seen - swift

Question

I'm trying to set 2 labels, one under other with different font size in the header. The function is called like this:
viewController.navigationItem.titleView = self.setHeader()
And code responsible for generating label is :
private func setHeader(agentName: String = "", isTyping: Bool = false) -> UIView {
let headerLabel: UILabel = {
let label = UILabel()
label.text = self.title
label.font = UIFont.systemFont(ofSize: 21)
label.textColor = UIColor.white
return label
}()
let subheaderLabel: UILabel = {
let label = UILabel()
label.font = UIFont.systemFont(ofSize: 10)
return label
}()
let headerView: UIView = {
let view = UIView()
view.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(headerLabel)
view.addConstraints([
NSLayoutConstraint(item: headerLabel, attribute: .centerY, relatedBy: .equal, toItem: view, attribute: .centerY, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: headerLabel, attribute: .leading, relatedBy: .equal, toItem: view, attribute: .leading, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: headerLabel, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 16),
NSLayoutConstraint(item: headerLabel, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 16)
])
return view
}()
if (!agentName.isEmpty) {
if (isTyping) {
subheaderLabel.text = agentName + " is typing ..."
} else {
subheaderLabel.text = agentName
}
headerView.addSubview(subheaderLabel)
}
return headerView
}
When I running IOS app there is nothing shown in the header. What is a reason?

Answer 1

I think you need to set the frame for the headerView. So in the initialization code for the headerView, use initializer with frame:
let headerView: UIView = {
// initialize the view with frame
let view = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 35))
// you want to call this on the headerLabel, not on view
headerLabel.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(headerLabel)
view.addConstraints([
NSLayoutConstraint(item: headerLabel, attribute: .centerY, relatedBy: .equal, toItem: view, attribute: .centerY, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: headerLabel, attribute: .leading, relatedBy: .equal, toItem: view, attribute: .leading, multiplier: 1.0, constant: 0),
NSLayoutConstraint(item: headerLabel, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 16),
NSLayoutConstraint(item: headerLabel, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 16)
])
return view
}()
Moreover, I believe headerLabel you want to set translatesAutoresizingMaskIntoConstraints on headerLabel rather than on headerView (headerView is positioned through frame and not Autolayout).
Also, notice that you add subheaderLabel to the view, but you never position it, don't forget about it either (although this should cause only subheaderLabel not to be rendered properly).