fix: 优化任务详情与图片预览布局

suixinkan/UI/TravelAlbum/TravelAlbumPhotoPreviewViewController.swift

@@ -91,7 +91,15 @@ final class TravelAlbumPhotoPreviewViewController: UIViewController {
         self.allowsActions = allowsActions
         super.init(nibName: nil, bundle: nil)
         modalPresentationStyle = .fullScreen
-        rebuildNodes(keepingProjectIndex: max(0, min(startProjectIndex, projects.count - 1)), kind: startKind)
+        let resolvedProjectIndex = max(0, min(startProjectIndex, self.projects.count - 1))
+        let initialProject = self.projects.indices.contains(resolvedProjectIndex)
+            ? self.projects[resolvedProjectIndex]
+            : nil
+        let resolvedStartKind = initialProject?.asset(for: startKind) == nil
+            ? initialProject?.orderedAssets.first?.kind ?? .original
+            : startKind
+        selectedKind = resolvedStartKind
+        rebuildNodes(keepingProjectIndex: resolvedProjectIndex, kind: resolvedStartKind)
     }
 
     @available(*, unavailable)
@@ -165,6 +173,7 @@ final class TravelAlbumPhotoPreviewViewController: UIViewController {
         sizeLabel.textColor = UIColor.white.withAlphaComponent(0.52)
         sizeLabel.font = .systemFont(ofSize: 13, weight: .regular)
         sizeLabel.textAlignment = .center
+        sizeLabel.accessibilityIdentifier = "travelAlbum.previewFileSizeLabel"
 
         counterLabel.textColor = UIColor.white.withAlphaComponent(0.82)
         counterLabel.font = .monospacedDigitSystemFont(ofSize: 15, weight: .medium)
@@ -423,7 +432,9 @@ final class TravelAlbumPhotoPreviewViewController: UIViewController {
         guard let node = currentNode else { return }
         let asset = currentAsset
         titleLabel.text = asset?.fileName.isEmpty == false ? asset?.fileName : "未命名照片"
-        sizeLabel.text = TravelAlbumDisplayFormatter.fileSizeText(asset?.fileSize ?? 0)
+        let fileSize = asset?.fileSize ?? 0
+        sizeLabel.text = fileSize > 0 ? TravelAlbumDisplayFormatter.fileSizeText(fileSize) : nil
+        sizeLabel.isHidden = fileSize <= 0
         counterLabel.text = "\(node.projectIndex + 1)/\(max(totalCount, projects.count))"
         counterLabel.accessibilityLabel = "第 \(node.projectIndex + 1) 张，共 \(max(totalCount, projects.count)) 张"
         highResolutionButton.isEnabled = asset != nil
@@ -982,6 +993,56 @@ extension TravelAlbumPhotoPreviewViewController: UICollectionViewDataSource, UIC
     }
 }
 
+/// 深色图片预览中使用的高对比度延迟加载指示器。
+@MainActor
+private final class TravelAlbumPreviewLoadingIndicator: Indicator {
+    private let containerView = UIView()
+    private let activityIndicator = UIActivityIndicatorView(style: .medium)
+    private var revealTask: Task<Void, Never>?
+
+    var view: IndicatorView { containerView }
+
+    init() {
+        containerView.backgroundColor = UIColor(red: 39 / 255, green: 39 / 255, blue: 42 / 255, alpha: 0.94)
+        containerView.layer.cornerRadius = 22
+        containerView.isAccessibilityElement = true
+        containerView.accessibilityIdentifier = "travelAlbum.previewLoadingIndicator"
+        containerView.accessibilityLabel = "图片加载中"
+        activityIndicator.color = UIColor.white.withAlphaComponent(0.92)
+        activityIndicator.transform = CGAffineTransform(scaleX: 1.2, y: 1.2)
+        containerView.addSubview(activityIndicator)
+        activityIndicator.snp.makeConstraints { $0.center.equalToSuperview() }
+    }
+
+    func startAnimatingView() {
+        revealTask?.cancel()
+        containerView.alpha = 0
+        containerView.isHidden = true
+        revealTask = Task { @MainActor [weak self] in
+            try? await Task.sleep(for: .milliseconds(150))
+            guard !Task.isCancelled, let self else { return }
+            activityIndicator.startAnimating()
+            containerView.isHidden = false
+            UIView.animate(
+                withDuration: UIAccessibility.isReduceMotionEnabled ? 0 : 0.12,
+                animations: { self.containerView.alpha = 1 }
+            )
+        }
+    }
+
+    func stopAnimatingView() {
+        revealTask?.cancel()
+        revealTask = nil
+        activityIndicator.stopAnimating()
+        containerView.alpha = 0
+        containerView.isHidden = true
+    }
+
+    func sizeStrategy(in imageView: KFCrossPlatformImageView) -> IndicatorSizeStrategy {
+        .size(CGSize(width: 44, height: 44))
+    }
+}
+
 /// 预览图片 Cell，使用 UIScrollView 提供远程加载、双击和双指缩放。
 private final class TravelAlbumPreviewImageCell: UICollectionViewCell, UIScrollViewDelegate {
     static let reuseIdentifier = "TravelAlbumPreviewImageCell"
@@ -1054,7 +1115,7 @@ private final class TravelAlbumPreviewImageCell: UICollectionViewCell, UIScrollV
 
         imageView.contentMode = .scaleAspectFit
         imageView.backgroundColor = .black
-        imageView.kf.indicatorType = .activity
+        imageView.kf.indicatorType = .custom(indicator: TravelAlbumPreviewLoadingIndicator())
         imageView.accessibilityIdentifier = "travelAlbum.previewImageView"
 
         retryButton.setTitle("图片加载失败，点击重试", for: .normal)