fix a bug about ios

ios/OralTrainer/Player/PlayerController.swift

@@ -18,6 +18,8 @@ final class PlayerController: ObservableObject {
 
     private var mediaItem: TrainingMediaItem?
     private var lastSentenceIndex: Int?
+    private var pendingSeekPositionMs: Int64?
+    private var seekGeneration = 0
     private var stopAtSentenceEnd = false
     private var stopAtSentenceEndIndex: Int?
     private var speedBeforeLongPress: Float?
@@ -67,6 +69,7 @@ final class PlayerController: ObservableObject {
 
     func load(_ item: TrainingMediaItem) {
         lastSentenceIndex = nil
+        pendingSeekPositionMs = nil
         stopAtSentenceEnd = false
         stopAtSentenceEndIndex = nil
         mediaItem = item
@@ -109,18 +112,17 @@ final class PlayerController: ObservableObject {
         stopAtSentenceEnd = false
         stopAtSentenceEndIndex = nil
         player.pause()
-        player.seek(to: .zero, toleranceBefore: .zero, toleranceAfter: .zero)
+        seek(to: .zero)
     }
 
     func seek(to positionMs: Int64) {
         stopAtSentenceEnd = false
         stopAtSentenceEndIndex = nil
-        let time = CMTime(seconds: Double(max(0, positionMs)) / 1000, preferredTimescale: 600)
+        performSeek(to: positionMs)
-        player.seek(to: time, toleranceBefore: .zero, toleranceAfter: .zero)
     }
 
     func seekRelative(_ deltaMs: Int64) {
-        seek(to: snapshot.positionMs + deltaMs)
+        seek(to: referencePositionMs() + deltaMs)
     }
 
     func rewind() {
@@ -138,7 +140,7 @@ final class PlayerController: ObservableObject {
         guard let item = mediaItem, !item.sentences.isEmpty else {
             return false
         }
-        let position = snapshot.positionMs
+        let position = referencePositionMs()
         guard let target = item.sentences.reversed().first(where: { $0.startMs < position - 250 })
             ?? item.sentences.first else {
             return false
@@ -152,7 +154,7 @@ final class PlayerController: ObservableObject {
         guard let item = mediaItem, !item.sentences.isEmpty else {
             return false
         }
-        let position = snapshot.positionMs
+        let position = referencePositionMs()
         guard let target = item.sentences.first(where: { $0.startMs > position + 150 }) else {
             return false
         }
@@ -177,8 +179,7 @@ final class PlayerController: ObservableObject {
         guard let sentence = currentSentence else {
             return
         }
-        let time = CMTime(seconds: Double(sentence.startMs) / 1000, preferredTimescale: 600)
+        performSeek(to: sentence.startMs)
-        player.seek(to: time, toleranceBefore: .zero, toleranceAfter: .zero)
         stopAtSentenceEnd = true
         stopAtSentenceEndIndex = sentence.index
         play()
@@ -277,9 +278,14 @@ final class PlayerController: ObservableObject {
             snapshot = PlaybackSnapshot(mediaId: mediaItem?.id, state: .idle, speed: currentSpeed())
             return
         }
-        let position = currentPositionMs()
+        let position = referencePositionMs()
+        if pendingSeekPositionMs == nil, lastSentenceIndex == nil {
+            lastSentenceIndex = sentence(at: position)?.index
+        }
+        if pendingSeekPositionMs == nil {
             enforceSentenceBoundary(positionMs: position)
-        let finalPosition = currentPositionMs()
+        }
+        let finalPosition = referencePositionMs()
         let sentence = sentence(at: finalPosition)
         if sentence?.index != lastSentenceIndex {
             lastSentenceIndex = sentence?.index
@@ -307,6 +313,34 @@ final class PlayerController: ObservableObject {
         return max(0, Int64(seconds * 1000))
     }
 
+    /// 连续手势/快进快退时使用 pending seek 的目标位置，避免仍基于旧的播放位置计算。
+    private func referencePositionMs() -> Int64 {
+        pendingSeekPositionMs ?? currentPositionMs()
+    }
+
+    /// AVPlayer 的 seek 是异步的；所有 seek 必须统一走这里，避免播放循环、
+    /// 用户手势和 seek 完成回调交错后把位置拉回旧句子。
+    private func performSeek(to positionMs: Int64) {
+        let targetPositionMs = max(0, positionMs)
+        seekGeneration += 1
+        let generation = seekGeneration
+        pendingSeekPositionMs = targetPositionMs
+        // 立即切换句子锚点。否则 periodic observer 仍可能以旧句子为锚点，
+        // 在 seek 完成前后把新位置拉回旧句开头。
+        lastSentenceIndex = sentence(at: targetPositionMs)?.index
+        let time = CMTime(seconds: Double(targetPositionMs) / 1000, preferredTimescale: 600)
+        player.seek(to: time, toleranceBefore: .zero, toleranceAfter: .zero) { [weak self] _ in
+            DispatchQueue.main.async {
+                guard let self, self.seekGeneration == generation else {
+                    return
+                }
+                self.pendingSeekPositionMs = nil
+                self.tick()
+            }
+        }
+        tick()
+    }
+
     private func durationMs(of item: AVPlayerItem) -> Int64 {
         let seconds = item.duration.seconds
         guard seconds.isFinite, seconds > 0 else {
@@ -393,8 +427,7 @@ final class PlayerController: ObservableObject {
     }
 
     private func seekRaw(_ positionMs: Int64) {
-        let time = CMTime(seconds: Double(max(0, positionMs)) / 1000, preferredTimescale: 600)
+        performSeek(to: positionMs)
-        player.seek(to: time, toleranceBefore: .zero, toleranceAfter: .zero)
     }
 
     private func handleEnded() {
@@ -402,7 +435,7 @@ final class PlayerController: ObservableObject {
             tick()
             return
         }
-        player.seek(to: .zero, toleranceBefore: .zero, toleranceAfter: .zero)
+        performSeek(to: .zero)
         player.play()
         tick()
     }

ios/OralTrainer/Player/PlayerSurfaceView.swift

@@ -5,24 +5,29 @@ import UIKit
 /// 与安卓端 OralTrainerPlayerView 对齐的播放区：
 /// - 单击：播放 / 暂停
 /// - 左划 / 右划：上一句 / 下一句（无句边界时回退为快退 / 快进）
+/// - 上划 / 下划：显示 / 隐藏字幕层（由 SwiftUI 横屏页接收）
 /// - 长按：按触摸点水平位置变速（左慢右快），松手恢复原速
 struct PlayerSurfaceView: UIViewRepresentable {
     let controller: PlayerController
+    var onVerticalSwipe: ((Bool) -> Void)?
 
     func makeUIView(context: Context) -> VideoSurfaceView {
         let view = VideoSurfaceView()
         view.playerLayer.player = controller.player
         view.controller = controller
+        view.onVerticalSwipe = onVerticalSwipe
         return view
     }
 
     func updateUIView(_ uiView: VideoSurfaceView, context: Context) {
         uiView.playerLayer.player = controller.player
+        uiView.onVerticalSwipe = onVerticalSwipe
     }
 }
 
 final class VideoSurfaceView: UIView {
     weak var controller: PlayerController?
+    var onVerticalSwipe: ((Bool) -> Void)?
 
     override class var layerClass: AnyClass {
         AVPlayerLayer.self
@@ -82,6 +87,12 @@ final class VideoSurfaceView: UIView {
         let velocity = recognizer.velocity(in: self)
         let dx = translation.x
         let dy = translation.y
+        if abs(dy) > abs(dx),
+           abs(dy) >= minSwipeDistance,
+           abs(velocity.y) >= minSwipeVelocity {
+            onVerticalSwipe?(dy < 0)
+            return
+        }
         guard abs(dx) >= abs(dy),
               abs(dx) >= minSwipeDistance,
               abs(velocity.x) >= minSwipeVelocity else {

ios/OralTrainer/Views/FullscreenPlayerView.swift

@@ -5,13 +5,31 @@ struct FullscreenPlayerView: View {
     @ObservedObject var controller: PlayerController
     let onExit: () -> Void
 
+    @State private var subtitleVisible = true
+
     var body: some View {
         ZStack {
             Color.black.ignoresSafeArea()
-            PlayerSurfaceView(controller: controller)
+            PlayerSurfaceView(controller: controller) { isSwipeUp in
+                guard subtitleVisible != isSwipeUp else {
+                    return
+                }
+                withAnimation(.easeInOut(duration: 0.22)) {
+                    subtitleVisible = isSwipeUp
+                }
+            }
                 .ignoresSafeArea()
+            HStack(spacing: 8) {
+                overlayPill(timeText)
+                Spacer()
+                overlayPill(Theme.formatSpeed(controller.snapshot.speed))
+            }
+            .padding(12)
+            .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .top)
+            .allowsHitTesting(false)
             VStack {
                 Spacer()
+                if subtitleVisible {
                     VStack(alignment: .leading, spacing: 6) {
                         Text(controller.currentItem?.title ?? "未选择课程")
                             .font(.system(size: 17, weight: .bold))
@@ -32,6 +50,8 @@ struct FullscreenPlayerView: View {
                     .padding(18)
                     .frame(maxWidth: .infinity, alignment: .leading)
                     .background(Theme.overlayFaint)
+                    .transition(.move(edge: .bottom).combined(with: .opacity))
+                }
             }
             VStack {
                 Spacer()
@@ -55,6 +75,11 @@ struct FullscreenPlayerView: View {
     @State private var progressDragging = false
     @State private var dragPositionMs: Int64 = 0
 
+    private var timeText: String {
+        let snapshot = controller.snapshot
+        return "\(Theme.formatTime(snapshot.positionMs)) / \(Theme.formatTime(snapshot.durationMs))"
+    }
+
     private var progressRow: some View {
         let duration = controller.snapshot.durationMs
         return HStack(spacing: 8) {
@@ -133,4 +158,14 @@ struct FullscreenPlayerView: View {
         }
         return controller.playbackStatusText(controller.snapshot)
     }
+
+    private func overlayPill(_ text: String) -> some View {
+        Text(text)
+            .font(.system(size: 13, weight: .bold))
+            .foregroundColor(.white)
+            .padding(.horizontal, 10)
+            .padding(.vertical, 6)
+            .background(Theme.overlay)
+            .clipShape(RoundedRectangle(cornerRadius: 8))
+    }
 }