Proper positioning of UIToolBar at the bottom of the screen - ios

Question

Due to lack of practice with creating UIToolBar element, I don't fully understand what is the cleanest way to position UIToolBar at the bottom of the screen. Now my code looks like this:
private lazy var toolBar: UIToolbar = {
let toolBar = UIToolbar(frame: CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height))
toolBar.translatesAutoresizingMaskIntoConstraints = false
let addNewNote = UIBarButtonItem(barButtonSystemItem: .compose, target: toolBar, action: nil)
let spacer = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: toolBar, action: nil)
toolBar.items = [spacer, addNewNote]
return toolBar
}()
private func setUpConstraints() {
NSLayoutConstraint.activate([
toolBar.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor),
toolBar.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor),
toolBar.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor)
])
}
This gives desired results, however I feel like I am missing a better way to implement this simple element. First of all, once the device is rotated, ToolBar doesn't fill all the space from leading to trailing, secondly assigning both leading/trailing constraints and width/height based on UIScreen.bounds property just doesn't seem right, although previously I saw a constraints layout issue of ToolBarElement in the console before I assigned this strange frame to my ToolBar. Now this issue is gone, but the situation did not become clearer.
My goal is to clone UIToolBar from iOS native notes app
So, as an experiences iOS developer (of course you are!) what would you recommend me to do?
Have a nice day!

Answer 1

If I understand well you can do it with autolayaout:
Declare your objects under your controller class:
let toolBar: UIToolbar = {
//let toolBar = UIToolbar(frame: CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)) // remove this
let toolBar = UIToolbar()
toolBar.translatesAutoresizingMaskIntoConstraints = false
let addNewNote = UIBarButtonItem(barButtonSystemItem: .compose, target: toolBar, action: nil)
let spacer = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: toolBar, action: nil)
toolBar.tintColor = .yourColor
let toolBarTitleLabel = UILabel()
toolBarTitleLabel.text = "150 Results"
toolBarTitleLabel.sizeToFit()
toolBarTitleLabel.backgroundColor = .clear
toolBarTitleLabel.textColor = .white
toolBarTitleLabel.textAlignment = .center
let topBarButtonItemTitleLabel = UIBarButtonItem(customView: toolBarTitleLabel)
toolBar.items = [spacer, topBarButtonItemTitleLabel, spacer, addNewNote]
return toolBar
}()
let mylabel2: UILabel = {
let label = UILabel()
label.text = "Your results data text here..."
label.textAlignment = .center
label.textColor = .gray
label.font = .systemFont(ofSize: 16, weight: .regular)
label.translatesAutoresizingMaskIntoConstraints = false
return label
}()
let dummyView: UIView = {
let v = UIView()
v.backgroundColor = .systemBlue
v.translatesAutoresizingMaskIntoConstraints = false
return v
}()
In viewDidLoad set constraints:
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .black
view.addSubview(toolBar)
NSLayoutConstraint.activate([
toolBar.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor),
toolBar.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor),
toolBar.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor)
])
view.addSubview(mylabel2)
NSLayoutConstraint.activate([
mylabel2.bottomAnchor.constraint(equalTo: toolBar.topAnchor),
mylabel2.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 30),
mylabel2.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -30),
mylabel2.heightAnchor.constraint(equalToConstant: 50)
])
view.addSubview(dummyView)
NSLayoutConstraint.activate([
dummyView.bottomAnchor.constraint(equalTo: mylabel2.topAnchor),
dummyView.leadingAnchor.constraint(equalTo: mylabel2.leadingAnchor),
dummyView.trailingAnchor.constraint(equalTo: mylabel2.trailingAnchor),
dummyView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 30)
])
}
This is the result: