103 lines
3.6 KiB
Swift
103 lines
3.6 KiB
Swift
//
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// ImagePreviewViewController.swift
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// suixinkan
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//
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import SnapKit
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import UIKit
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/// 图片全屏预览，对齐 Android `MediaPreviewDialog`。
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final class ImagePreviewViewController: UIViewController {
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private let imageURLs: [String]
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private let startIndex: Int
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private let scrollView = UIScrollView()
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private let pageControl = UIPageControl()
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init(imageURLs: [String], startIndex: Int) {
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self.imageURLs = imageURLs
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self.startIndex = min(max(0, startIndex), max(0, imageURLs.count - 1))
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super.init(nibName: nil, bundle: nil)
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modalPresentationStyle = .fullScreen
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}
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@available(*, unavailable)
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required init?(coder: NSCoder) {
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fatalError("init(coder:) has not been implemented")
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}
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override func viewDidLoad() {
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super.viewDidLoad()
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view.backgroundColor = .black
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scrollView.isPagingEnabled = true
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scrollView.showsHorizontalScrollIndicator = false
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scrollView.delegate = self
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pageControl.numberOfPages = imageURLs.count
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pageControl.currentPage = startIndex
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pageControl.isHidden = imageURLs.count <= 1
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let closeButton = UIButton(type: .system)
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closeButton.setImage(UIImage(systemName: "xmark"), for: .normal)
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closeButton.tintColor = .white
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closeButton.addTarget(self, action: #selector(closeTapped), for: .touchUpInside)
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view.addSubview(scrollView)
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view.addSubview(pageControl)
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view.addSubview(closeButton)
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scrollView.snp.makeConstraints { make in
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make.edges.equalToSuperview()
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}
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pageControl.snp.makeConstraints { make in
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make.bottom.equalTo(view.safeAreaLayoutGuide).inset(AppSpacing.md)
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make.centerX.equalToSuperview()
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}
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closeButton.snp.makeConstraints { make in
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make.top.equalTo(view.safeAreaLayoutGuide).offset(AppSpacing.sm)
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make.trailing.equalToSuperview().inset(AppSpacing.md)
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make.size.equalTo(AppSpacing.minTouchTarget)
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}
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imageURLs.enumerated().forEach { index, url in
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let imageView = UIImageView()
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imageView.contentMode = .scaleAspectFit
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imageView.loadRemoteImage(urlString: url, placeholderColor: .darkGray)
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scrollView.addSubview(imageView)
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imageView.snp.makeConstraints { make in
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make.top.bottom.equalToSuperview()
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make.width.equalTo(view.snp.width)
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make.height.equalTo(view.snp.height)
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make.leading.equalToSuperview().offset(CGFloat(index) * view.bounds.width)
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}
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}
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}
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override func viewDidLayoutSubviews() {
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super.viewDidLayoutSubviews()
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scrollView.contentSize = CGSize(width: view.bounds.width * CGFloat(imageURLs.count), height: view.bounds.height)
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scrollView.setContentOffset(CGPoint(x: view.bounds.width * CGFloat(startIndex), y: 0), animated: false)
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scrollView.subviews.enumerated().forEach { index, subview in
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subview.frame = CGRect(
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x: view.bounds.width * CGFloat(index),
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y: 0,
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width: view.bounds.width,
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height: view.bounds.height
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)
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}
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}
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@objc private func closeTapped() {
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dismiss(animated: true)
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}
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}
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extension ImagePreviewViewController: UIScrollViewDelegate {
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func scrollViewDidScroll(_ scrollView: UIScrollView) {
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guard view.bounds.width > 0 else { return }
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let page = Int(round(scrollView.contentOffset.x / view.bounds.width))
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pageControl.currentPage = page
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}
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}
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