使用 ViewCode 点击按钮 Swift 时滚动 ScrollView

Question

我正在使用 ViewCode 在 Swift 中创建一个 ViewPager。 我需要创建以下操作：点击 Next 按钮（方法：actionNextPressed()），然后将滚动视图滚动到下一页（就像向右或向左滚动的 TapGesture）。 这是我的 Swift 代码，到目前为止我尝试过的代码，以及来自 viewpager 的打印屏幕（目前）

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

我曾经在 collectionView 上遇到过同样的问题。您必须关闭 .isPagingEnabled，将滚动视图滚动到您想要的位置，然后将其重新打开分页。

 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

}