.tag on slider not changing the alpha of imagview - swift

Question

My swift code below has 2 different buttons which should effect the slider baised on the .tagnumber they initialize. B1 should effect the alhpa or transpency of the imageivew and b2 should decrease / increase the size. What b2 does works. What B1 does not work.My code does not use any storyboards. Also the uislider should only do one task it cannont resize the imageview and change the alpha at the same time. Only 1 task.
import UIKit
class ViewController: UIViewController {
var pzc = UIImageView()
var s = UISlider()
var b1 = UIButton()
var b2 = UIButton()
var jessicaAlba:Float = 50
var topConstraint: NSLayoutConstraint!
var heightConstraint: NSLayoutConstraint!
var leadingConstraint: NSLayoutConstraint!
var trailingConstraint: NSLayoutConstraint!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
[pzc,s,b1,b2].forEach {
$0.translatesAutoresizingMaskIntoConstraints = false
view.addSubview($0)
}
[b1,b2].forEach {
$0.backgroundColor = .systemRed
}
pzc.backgroundColor = .systemGray
b1.frame = CGRect(x: view.center.x-115, y: view.center.y+200, width: 30, height: 30)
b2.frame = CGRect(x: view.center.x-115, y: view.center.y+250, width: 30, height: 30)
s.addTarget(self, action: #selector(moveRight), for: .touchUpInside)
b1.addTarget(self, action: #selector(mr1), for: .touchUpInside)
b2.addTarget(self, action: #selector(mr2), for: .touchUpInside)
NSLayoutConstraint.activate ([
b1.trailingAnchor.constraint(equalTo: view.centerXAnchor, constant :37.5),
b1.topAnchor.constraint(equalTo: view.centerYAnchor, constant : 225),
b1.widthAnchor.constraint(equalToConstant: 75),
b1.heightAnchor.constraint(equalToConstant: 50),
b2.trailingAnchor.constraint(equalTo: view.centerXAnchor, constant :130),
b2.topAnchor.constraint(equalTo: view.centerYAnchor, constant : 225),
b2.widthAnchor.constraint(equalToConstant: 75),
b2.heightAnchor.constraint(equalToConstant: 50),
])
s.minimumValue = 50
s.maximumValue = 200
s.setValue(jessicaAlba, animated: false)
view.addSubview(s)
s.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 10).isActive = true
s.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -10).isActive = true
s.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -10).isActive = true
pzc.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(pzc)
topConstraint = pzc.topAnchor.constraint(equalTo: view.topAnchor, constant: CGFloat(jessicaAlba))
topConstraint.isActive = true
heightConstraint = pzc.heightAnchor.constraint(equalTo: view.heightAnchor , multiplier: 0.5, constant: CGFloat(-jessicaAlba))
heightConstraint.isActive = true
leadingConstraint = pzc.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: CGFloat(jessicaAlba))
leadingConstraint.isActive = true
trailingConstraint = pzc.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: CGFloat(-jessicaAlba))
trailingConstraint.isActive = true
}
#objc func moveRight() {
if s.tag == 1 {
pzc.alpha = CGFloat(s.value)
}
if s.tag == 2 {
changeSize()
}
}
#objc func changeSize() {
UIView.animate(withDuration: 0.5, animations: {
self.jessicaAlba = self.s.value
self.topConstraint.constant = CGFloat(self.jessicaAlba)
self.heightConstraint.constant = CGFloat(-self.jessicaAlba)
self.leadingConstraint.constant = CGFloat(self.jessicaAlba)
self.trailingConstraint.constant = CGFloat(-self.jessicaAlba)
self.view.layoutIfNeeded()
}) { (finished) in
}
}
#objc func mr1() {
b1.backgroundColor = .brown
b2.backgroundColor = .systemPink
s.tag = 1
}
#objc func mr2() {
b2.backgroundColor = .brown
b1.backgroundColor = .systemPink
s.tag = 2
}
}

Answer 1

Here multiple target are added on your UISlider. Just modify your function.
#objc func moveRight() {
if s.tag == 1 {
let diff = s.maximumValue-s.minimumValue
pzc.alpha = CGFloat(s.value/diff)
}
if s.tag == 2 {
changeSize()
}
}
You can also modify your changeSize() function for animation.
#objc func changeSize() {
UIView.animate(withDuration: 0.5, animations: {
self.jessicaAlba = self.s.value
self.topConstraint.constant = CGFloat(self.jessicaAlba)
self.heightConstraint.constant = CGFloat(-self.jessicaAlba)
self.leadingConstraint.constant = CGFloat(self.jessicaAlba)
self.trailingConstraint.constant = CGFloat(-self.jessicaAlba)
self.view.layoutIfNeeded()
}) { (finished) in
}
}