263 lines
10 KiB
Swift
263 lines
10 KiB
Swift
import SwiftUI
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import UIKit
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/// 带缓存、并发控制、图片解密、双指选择效果和分享功能的异步图片视图
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struct AsyncImageView: View {
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let url: String
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let nums: [Int]
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let index: Int
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@State private var image: UIImage?
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@State private var isLoading = false
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@State private var error: Error?
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@State private var isSelecting = false // 是否处于选择状态
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@State private var pressStartTime: Date?
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@State private var longPressActive = false
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@State private var showShareSheet = false // 控制分享面板显示
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private static var currentlyLoadingIndices: Set<Int> = []
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private static let maxConcurrentLoads = 4
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private static let longPressThreshold: TimeInterval = 0.1 // 长按阈值（秒）
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var body: some View {
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Group {
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if let image = image {
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ZStack(alignment: .center) {
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// 原始图片
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Image(uiImage: image)
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.resizable()
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.aspectRatio(contentMode: .fit)
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// 选择状态的视觉效果
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if isSelecting {
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Image(uiImage: image)
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.resizable()
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.aspectRatio(contentMode: .fit)
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.colorMultiply(.white)
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.opacity(0.7)
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.overlay(
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RoundedRectangle(cornerRadius: 4)
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.stroke(Color.blue, lineWidth: 3) // 改为蓝色边框更醒目
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)
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.blendMode(.lighten)
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// 分享按钮（仅在选择状态显示）
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VStack {
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Spacer()
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Button(action: {
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showShareSheet = true
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}) {
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Image(systemName: "square.and.arrow.up")
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.foregroundColor(.white)
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.padding()
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.background(Color.blue)
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.clipShape(Circle())
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.shadow(radius: 4)
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}
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.padding()
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}
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}
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}
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// 双指手势识别
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.gesture(
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MagnificationGesture(minimumScaleDelta: 0)
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.onChanged { _ in
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handleTwoFingerGesture()
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}
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.onEnded { _ in
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// 只有长按超过阈值才保持选择状态
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let shouldKeepSelection = pressStartTime.map {
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Date().timeIntervalSince($0) >= Self.longPressThreshold
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} ?? false
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withAnimation(.easeOut) {
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isSelecting = shouldKeepSelection
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}
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if !shouldKeepSelection {
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pressStartTime = nil
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longPressActive = false
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}
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}
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)
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// 分享视图
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.sheet(isPresented: $showShareSheet) {
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ShareSheet(activityItems: [image]) { completed in
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if completed {
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withAnimation(.easeOut) {
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isSelecting = false
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}
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pressStartTime = nil
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longPressActive = false
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}
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}
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}
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} else if isLoading {
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ProgressView()
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.frame(height: 200)
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} else if error != nil {
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VStack(spacing: 8) {
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Image(systemName: "exclamationmark.triangle")
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.foregroundColor(.red)
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Text(error?.localizedDescription ?? "未知错误")
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.font(.caption)
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.foregroundColor(.gray)
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}
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.frame(height: 200)
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} else {
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Color.gray.opacity(0.3)
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.frame(height: 200)
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}
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}
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.onAppear {
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loadImage()
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}
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.onDisappear {
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Self.currentlyLoadingIndices.remove(index)
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}
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}
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// 处理双指手势
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private func handleTwoFingerGesture() {
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if pressStartTime == nil {
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pressStartTime = Date()
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} else {
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// 检查是否超过长按阈值
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let pressDuration = Date().timeIntervalSince(pressStartTime!)
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if pressDuration >= Self.longPressThreshold && !longPressActive {
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longPressActive = true
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// 显示选择效果
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withAnimation(.easeIn) {
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isSelecting = true
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}
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}
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}
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}
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// 图片加载核心逻辑
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private func loadImage() {
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let cacheKey = extractCacheKey(from: url)
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// 1. 先检查缓存，如果有直接使用
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if let cachedImage = ImageCacheManager.shared.getImage(for: cacheKey) {
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image = cachedImage
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print("从缓存加载 - 键: \(cacheKey)")
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return
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}
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// 2. 检查并发加载限制
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guard !Self.currentlyLoadingIndices.contains(index),
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Self.currentlyLoadingIndices.count < Self.maxConcurrentLoads else {
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return
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}
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// 3. 开始加载流程
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Self.currentlyLoadingIndices.insert(index)
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isLoading = true
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error = nil
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// 4. 验证解密参数
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guard let decodeNum = nums[safe: index] else {
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error = NSError(domain: "数据错误", code: 1, userInfo: [NSLocalizedDescriptionKey: "图片参数不匹配"])
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isLoading = false
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Self.currentlyLoadingIndices.remove(index)
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return
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}
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print("调试信息：加载图片 - URL: \(url), 缓存键: \(cacheKey), 解密参数: \(decodeNum), 索引: \(index)")
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// 5. 验证URL有效性
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guard let imageUrl = URL(string: url) else {
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error = NSError(domain: "URL错误", code: 2, userInfo: [NSLocalizedDescriptionKey: "无效的图片URL"])
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isLoading = false
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Self.currentlyLoadingIndices.remove(index)
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return
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}
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// 6. 网络请求加载图片
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URLSession.shared.dataTask(with: imageUrl) { data, response, error in
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DispatchQueue.main.async {
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// 清理加载状态
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Self.currentlyLoadingIndices.remove(index)
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self.isLoading = false
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// 处理网络错误
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if let error = error {
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self.error = error
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print("图片加载失败（网络错误）: \(error.localizedDescription)")
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return
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}
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// 验证响应和数据
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guard let httpResponse = response as? HTTPURLResponse,
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(200...299).contains(httpResponse.statusCode),
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let data = data, !data.isEmpty else {
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self.error = NSError(domain: "响应错误", code: 3, userInfo: [NSLocalizedDescriptionKey: "无效的服务器响应"])
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print("图片加载失败（无效响应）")
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return
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}
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// 解码图片并应用解密
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guard let loadedImage = UIImage(data: data) else {
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self.error = NSError(domain: "解码错误", code: 4, userInfo: [NSLocalizedDescriptionKey: "无法解析图片数据"])
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print("图片加载失败（数据无效）")
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return
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}
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// 解密并缓存图片（使用简化键）
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let decodedImage = loadedImage.decodeImage(num: decodeNum)
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self.image = decodedImage
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ImageCacheManager.shared.saveImage(decodedImage, for: cacheKey)
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print("图片加载成功（已缓存） - 键: \(cacheKey)")
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}
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}.resume()
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}
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/// 从URL中提取简化的缓存键
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private func extractCacheKey(from urlString: String) -> String {
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guard let url = URL(string: urlString) else {
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return urlString.hashValue.description
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}
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let pathComponents = url.pathComponents
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if let photosIndex = pathComponents.firstIndex(of: "photos"),
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photosIndex + 1 < pathComponents.count,
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photosIndex + 2 < pathComponents.count {
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let idComponent = pathComponents[photosIndex + 1]
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var fileComponent = pathComponents[photosIndex + 2]
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if let dotIndex = fileComponent.lastIndex(of: ".") {
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fileComponent = String(fileComponent[..<dotIndex])
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}
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return "\(idComponent)/\(fileComponent)"
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}
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return url.path.hashValue.description
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}
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}
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// 分享视图包装器
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struct ShareSheet: UIViewControllerRepresentable {
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let activityItems: [Any]
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let completion: (Bool) -> Void
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func makeUIViewController(context: Context) -> UIActivityViewController {
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let controller = UIActivityViewController(activityItems: activityItems, applicationActivities: nil)
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controller.completionWithItemsHandler = { (activityType, completed, returnedItems, error) in
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completion(completed)
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}
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return controller
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}
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func updateUIViewController(_ uiViewController: UIActivityViewController, context: Context) {}
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}
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// 数组安全访问扩展
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extension Array {
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subscript(safe index: Int) -> Element? {
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return indices.contains(index) ? self[index] : nil
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}
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}
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