VerticalProgressViewController.swift

class VerticalProgressViewController: UIViewController {
	
	let theButton: UIButton = {
		let v = UIButton()
		v.translatesAutoresizingMaskIntoConstraints = false
		v.setTitle("Tap Me", for: .normal)
		v.setTitleColor(.red, for: .normal)
		return v
	}()
	
	let vProgView: VerticalProgressView = {
		let v = VerticalProgressView()
		v.translatesAutoresizingMaskIntoConstraints = false
		return v
	}()
	
	var p = Float(0.0)
	
	override func viewDidLoad() {
		super.viewDidLoad()

		view.addSubview(theButton)
		view.addSubview(vProgView)
		
		NSLayoutConstraint.activate([
			
			// add button 40-pts from top, centered vertically
			theButton.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 40.0),
			theButton.centerXAnchor.constraint(equalTo: view.centerXAnchor),

			// add vertical progress view constrained 40-pts top, leading, bottom, and width 40
			vProgView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 40.0),
			vProgView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: -40.0),
			vProgView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 40.0),
			vProgView.widthAnchor.constraint(equalToConstant: 40.0),

			])
		
		// initialize at 0.0
		vProgView.setProgress(p, animated: false)
		
		theButton.addTarget(self, action: #selector(didTap(_:)), for: .touchUpInside)
		
	}
	
	@objc func didTap(_ sender: Any) {
		// increment the progress by 0.05 (5%) with each tap
		p += 0.05
		vProgView.setProgress(p, animated: true)
	}
	
}