How to move scrollview with buttons only in SwiftUI - swiftui

Question

Previously I did with Swift4 UIScrollView which scrolled with buttons and x offset.
In Swift4 I have:
Set Scrolling Enabled and Paging Enabled to false.
Created the margins, offsets for each frame in UIScrollView and changed the position with buttons Back and Next.
Here is the code:
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var buttonSound: UIButton!
#IBOutlet weak var buttonPrev: UIButton!
#IBOutlet weak var buttonNext: UIButton!
#IBOutlet weak var scrollView: UIScrollView!
var levels = ["level1", "level2", "level3", "level4"]
let screenWidth = UIScreen.main.bounds.width
let screenHeight = UIScreen.main.bounds.height
var currentLevel = 1
var previousLevel: Int? = nil
override func viewDidLoad() {
super.viewDidLoad()
//Defining the Various Swipe directions (left, right, up, down)
let swipeLeft = UISwipeGestureRecognizer(target: self, action: #selector(self.handleGesture(gesture:)))
swipeLeft.direction = .left
self.view.addGestureRecognizer(swipeLeft)
let swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(self.handleGesture(gesture:)))
swipeRight.direction = .right
self.view.addGestureRecognizer(swipeRight)
addHorizontalLevelsList()
customizeButtons()
resizeSelected()
}
func addHorizontalLevelsList() {
var frame : CGRect?
for i in 0..<levels.count {
let button = UIButton(type: .custom)
let buttonW = screenWidth/3
let buttonH = screenHeight/2
frame = CGRect(x: CGFloat(i+1) * (screenWidth/2) - (buttonW/2),
y: buttonH - 100,
width: buttonW,
height: buttonH)
button.frame = frame!
button.tag = i+1
button.backgroundColor = .lightGray
button.addTarget(self, action: #selector(selectTeam), for: .touchUpInside)
button.setTitle(levels[i], for: .normal)
scrollView.addSubview(button)
}
scrollView.contentSize = CGSize(width: (screenWidth/2 * CGFloat(levels.count)),
height: screenHeight)
scrollView.backgroundColor = .clear
self.view.addSubview(scrollView)
}
func customizeButtons(){
buttonPrev.frame = CGRect(x: 0,
y: (screenHeight/2) - 40,
width: 80, height: 80)
buttonNext.frame = CGRect(x: screenWidth - 80,
y: (screenHeight/2) - 40,
width: 80, height: 80)
buttonPrev.superview?.bringSubviewToFront(buttonPrev)
buttonNext.superview?.bringSubviewToFront(buttonNext)
}
#objc func selectTeam(button: UIButton) {
button.transform = CGAffineTransform(scaleX: 0.6, y: 0.6)
UIView.animate(withDuration: 1.0,
delay: 0,
usingSpringWithDamping: CGFloat(0.20),
initialSpringVelocity: CGFloat(6.0),
options: UIView.AnimationOptions.allowUserInteraction,
animations: {
button.transform = CGAffineTransform.identity
},
completion: { Void in() }
)
print(levels[button.tag])
let vc = PopTypeVC(nibName: "PopTypeVC", bundle: nil)
vc.modalPresentationStyle = UIModalPresentationStyle.overCurrentContext
self.present(vc, animated: true)
}
#IBAction func prevLevel(_ sender: Any) {
if currentLevel > 0 {
currentLevel -= 1
scroll()
}
}
#IBAction func nextLevel(_ sender: Any) {
if currentLevel < levels.count {
currentLevel += 1
scroll()
}
}
func scroll(){
print(currentLevel)
print(previousLevel as Any)
scrollView.setContentOffset(CGPoint(x: currentLevel * Int(screenWidth/2), y: 0), animated: true)
resizeSelected()
}
// The #objc before func is a must, since we are using #selector (above)
#objc func handleGesture(gesture: UISwipeGestureRecognizer) -> Void {
if gesture.direction == UISwipeGestureRecognizer.Direction.right {
prevLevel(self)
}
else if gesture.direction == UISwipeGestureRecognizer.Direction.left {
nextLevel(self)
}
}
func resizeSelected(){
if previousLevel != nil {
let previousFrame = CGRect(x:CGFloat(previousLevel!) * (screenWidth/2) - (screenWidth/3)/2,
y: (screenHeight/2) - 100,
width: screenWidth/3,
height: screenHeight/2)
scrollView.viewWithTag(previousLevel!)?.frame = previousFrame
}
let currentFrame = CGRect(x: CGFloat(currentLevel) * (screenWidth/2) - (screenWidth/3)/2 - 10,
y: (screenHeight/2) - 110,
width: screenWidth/3 + 20,
height: screenHeight/2 + 20)
scrollView.viewWithTag(currentLevel)?.frame = currentFrame
previousLevel = currentLevel
}
}
The problem is I can't do this with SwiftUI:
struct ContentView: View {
static var levels = ["level1",
"level2",
"level3",
"level4"]
var currentLevel = 1
var previousLevel: Int? = nil
let screenW = UIScreen.main.bounds.width
let screenH = UIScreen.main.bounds.height
let margin1 = 50
let margin2 = 100
let margin3 = 20
let sceneButtonW = 100
let buttonPadding = 40
var body: some View {
ZStack {
// Horizontal list
VStack {
Spacer()
.frame(height: margin2)
ScrollView(.horizontal, showsIndicators: false) {
HStack{
Spacer()
.frame(width: buttonPadding + sceneButtonW/2)
ForEach(0..<ContentView.levels.count) { i in
cardView(i: i).tag(i+1)
}
Spacer()
.frame(width: buttonPadding + sceneButtonW/2)
}
}
Spacer()
.frame(height: margin3)
}
}
.background(Image("bg")
.resizable()
.edgesIgnoringSafeArea(.all)
.aspectRatio(contentMode: .fill))
}
}
Question: Are there any methods to disable automatic scrolling at all and use offsets at ScrollView with SwiftUI?

Answer 1

This already built solution for SwiftUI
https://github.com/fermoya/SwiftUIPager
However, there is no real example.