Scroll the ScrollView when tap a button Swift with ViewCode - ios

Question

I'm creating a ViewPager in Swift using ViewCode.
I need to create the following action: tap on the Next button (method: actionNextPressed() ), and scroll the scrollview to the next page (like a TapGesture scrolling to right or left).
Here is my Swift code, what I've tried until now, and the printscreen from the viewpager (at the moment)
PagerViewController.swift
import UIKit
import SnapKit
open class PagerViewController: UIViewController, UIPageViewControllerDelegate {
private lazy var dimmedView: UIView = {
let view = UIView()
view.backgroundColor = .black
view.alpha = maxDimmedAlpha
return view
}()
private lazy var containerView: UIView = {
let view = UIView()
view.backgroundColor = UIColor(white: 1, alpha: 0)
return view
}()
lazy var scrollView: UIScrollView = {
let scrollView = UIScrollView()
scrollView.showsHorizontalScrollIndicator = false
scrollView.isPagingEnabled = true
scrollView.contentSize = CGSize(width: view.frame.width * CGFloat(pages.count), height: containerView.frame.height)
for i in 0..<pages.count {
var page = pages[i]
let dialog = PageViewController(
icon: page.icon,
titleText: page.title,
descriptionText: page.description,
titleActionButton: page.titleButton,
actionButton: page.actionButton
)!
scrollView.addSubview(dialog.view)
scrollView.subviews[i].frame = CGRect(
x: view.frame.width * CGFloat(i),
y: 0,
width: containerView.frame.width,
height: containerView.frame.height
)
}
scrollView.delegate = self
return scrollView
}()
lazy var pageControl: UIPageControl = {
let pageControl = UIPageControl()
pageControl.currentPage = 0
pageControl.numberOfPages = pages.count
pageControl.addTarget(self, action: #selector(pageControlTapHandler(sender:)), for: .allEvents)
pageControl.isUserInteractionEnabled = false
pageControl.pageIndicatorTintColor = .systemGray
pageControl.currentPageIndicatorTintColor = .systemBlue
pageControl.backgroundColor = .white
return pageControl
}()
private lazy var directionsButtonsStackView: UIStackView = {
let view = UIStackView()
view.axis = .horizontal
view.distribution = .fillEqually
view.backgroundColor = .red
return view
}()
private lazy var buttonJump = UIButton()
private lazy var buttonBefore = UIButton()
private lazy var buttonNext = UIButton()
private var titleJumpButton: String! = ""
private let maxDimmedAlpha: CGFloat = 0.6
open var pages: Array<PageModel>!
private var currentPage: Int = 0
init?(listPages: Array<PageModel>, titleJumpButton: String) {
super.init(nibName: nil, bundle: nil)
self.pages = listPages
self.titleJumpButton = titleJumpButton
}
required public init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
#objc func pageControlTapHandler(sender: UIPageControl) {
scrollView.scrollTo(horizontalPage: sender.currentPage)
}
open override func viewDidLoad() {
super.viewDidLoad()
setupView()
addViewComponents()
setupConstraints()
}
private func setupView() {
self.buttonJump = PageButton(frame: .zero).build(
context: self,
title: titleJumpButton!,
selector: #selector(actionJumpPressed)
)
self.buttonBefore = PageButton(frame: .zero).build(
context: self,
title: "Before",
selector: #selector(actionBeforePressed)
)
self.buttonBefore.backgroundColor = .white
self.buttonNext = PageButton(frame: .zero).build(
context: self,
title: "Next",
selector: #selector(actionNextPressed)
)
self.buttonJump.setTitle(titleJumpButton, for: .normal)
}
private func addViewComponents() {
view.addSubview(dimmedView)
containerView.addSubview(scrollView)
containerView.addSubview(pageControl)
directionsButtonsStackView.addArrangedSubview(buttonBefore)
directionsButtonsStackView.addArrangedSubview(buttonNext)
containerView.addSubview(directionsButtonsStackView)
containerView.addSubview(buttonJump)
view.addSubview(containerView)
}
private func setupConstraints() {
dimmedView.snp.makeConstraints { make in
make.top.equalToSuperview()
make.bottom.equalToSuperview()
make.leading.equalToSuperview()
make.trailing.equalToSuperview()
}
containerView.snp.makeConstraints { make in
make.top.equalToSuperview().offset(100)
make.bottom.equalToSuperview().inset(100)
make.leading.equalToSuperview()
make.trailing.equalToSuperview()
make.centerX.equalToSuperview()
make.centerY.equalToSuperview()
make.margins.equalTo(20)
}
scrollView.snp.makeConstraints { make in
make.top.equalToSuperview()
make.bottom.equalTo(pageControl.snp.top)
make.leading.equalTo(containerView.snp.leading)
make.trailing.equalTo(containerView.snp.trailing)
}
pageControl.snp.makeConstraints { make in
make.bottom.equalTo(directionsButtonsStackView.snp.top)
make.leading.equalTo(containerView.snp.leading).offset(20)
make.trailing.equalTo(containerView.snp.trailing).inset(20)
make.height.equalTo(30)
make.centerX.equalToSuperview()
}
directionsButtonsStackView.snp.makeConstraints { make in
make.bottom.equalTo(buttonJump.snp.top)
make.leading.equalTo(containerView.snp.leading).offset(20)
make.trailing.equalTo(containerView.snp.trailing).inset(20)
make.height.equalTo(60)
make.width.greaterThanOrEqualTo(0)
make.centerX.equalToSuperview()
}
buttonJump.snp.makeConstraints { make in
make.bottom.equalToSuperview().inset(10)
make.leading.equalTo(containerView).offset(20)
make.trailing.equalTo(containerView).inset(20)
make.centerX.equalToSuperview()
make.width.greaterThanOrEqualTo(0)
make.height.equalTo(50)
}
}
#objc private func actionJumpPressed() {
self.dismiss(animated: true, completion: nil)
}
#objc private func actionBeforePressed() {
if currentPage == 0 {
return
} else {
currentPage -= 1
pageControl.currentPage = currentPage
}
}
#objc private func actionNextPressed() {
if currentPage == pages.count {
return
} else {
currentPage += 1
pageControl.currentPage = currentPage
}
}
}
extension PagerViewController: UIScrollViewDelegate {
public func scrollViewDidScroll(_ scrollView: UIScrollView) {
let pageIndex = Int(round(scrollView.contentOffset.x / view.frame.width))
pageControl.currentPage = pageIndex
currentPage = pageIndex
}
}
extension UIScrollView {
func scrollTo(horizontalPage: Int? = 0) {
var frame: CGRect = self.frame
frame.origin.x = frame.size.width * CGFloat(horizontalPage ?? 0)
self.scrollRectToVisible(frame, animated: true)
}
}

Answer 1

I had the same issue once with a collectionView. You have to turn off the .isPagingEnabled, scroll the scrollview where you want and turn it back on the paging.
func scrollTo(horizontalPage: Int? = 0) {
scrollView.isPagingEnabled = false
var frame: CGRect = self.frame
frame.origin.x = frame.size.width * CGFloat(horizontalPage ?? 0)
self.scrollRectToVisible(frame, animated: true)
scrollView.isPagingEnabled = true
}