Swift UIButton not appearing on screen - swift

Question

I have a view in my tabbar controller where I would like to show a button. I create this button programmatically based of a condition, therefore I use the following code but nothing is appearing:
override func viewDidLoad() {
super.viewDidLoad()
if !Settings.getIsConnected() {
notConnected()
}
}
func notConnected() {
let connectBtn = UIButton(frame: CGRect(x: self.view.center.x, y: self.view.center.y, width: 200, height: 45))
connectBtn.setTitle("Connect", forState: .Normal)
connectBtn.addTarget(self, action:#selector(self.pressedConnect(_:)), forControlEvents: .TouchUpInside)
self.view.addSubview(connectBtn)
print("Button created")
}
func pressedConnect(sender: UIButton!) {
}
I am clueless on what I am doing wrong. Anyone got suggestions? Cause it does print out "Button created" so it definitely runs the code inside the noConnected() method.

Answer 1

Add a background color to your UIButton and add a tint color to the title. This will resolve the problem

Answer 2

Try moving the code to viewDidAppear and see if the button is showing up.
The frame is not correctly set when in viewDidLoad. Use the method viewDidLayoutSubviews for the earliest possible time where the frame is correctly setup for a ViewController.
With this code change, you will need some additional logic for when your button should be added as a subview though.

Answer 3

A programmatically created button may not show up because of more reasons, e.g:
the tint color is not set
the background color is not set
the button is not added to the view hierarchy
the button is hidden
In your case, you should change the tint color or the background color of your button.
E.g.:
Swift 4.2:
private lazy var connectButton: UIButton = {
let button = UIButton(type: .custom)
button.backgroundColor = .green
button.setTitleColor(.black, for: .normal)
button.setTitle(NSLocalizedString("Connect", comment: ""), for: .normal)
button.translatesAutoresizingMaskIntoConstraints = false
return button
}()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(connectButton)
}

Answer 4

You can re-check the button properties in the storyboard that it is not hidden.