beautified some ui

android/README.md

@@ -24,6 +24,22 @@ the course service or extracted from subtitle/speech analysis data.
 These defaults match the desktop player's arrow-key workflow while fitting a
 tablet touch screen.
 
+## Sentence Playback Modes
+
+`PlayerConfig.continuousPlayback` controls how playback crosses sentence
+boundaries:
+
+- `true` (default): the video plays continuously through all sentences.
+- `false`: playback stays on the current sentence; when its boundary is
+  reached, playback loops back to the start of the same sentence until the
+  student swipes to the previous/next sentence.
+
+Toggle it at runtime with `controller.setContinuousPlayback(enabled)`.
+
+`controller.playCurrentSentenceAndStop()` plays only the current sentence and
+automatically pauses once it finishes — useful for a "play the reference
+sentence" button in a recording test flow.
+
 ## Basic Integration
 
 ```kotlin
@@ -123,6 +139,63 @@ sdk.videoCatalogApi.fetch(object : VideoCatalogCallback {
 })
 ```
 
+## Sample App Configuration
+
+The sample app points at the cloud service through the `SERVER_BASE_URL`
+constant at the top of `MainActivity.kt`:
+
+```kotlin
+const val SERVER_BASE_URL = "https://videoservice.d1kt.cn"
+```
+
+Change it to your real deployment address before building the APK. For a LAN
+or development server, an `http://<server-ip>:<port>` address works because the
+sample app permits cleartext HTTP (see
+`res/xml/network_security_config.xml`); production should keep HTTPS.
+
+The sample app also enables `allowHttpFallback`: if an `https://` request fails
+with a TLS error (for example a misconfigured or unstable gateway/certificate),
+the SDK automatically retries the same request over plain HTTP. This is a
+convenience for private deployments only — fix the TLS edge in production.
+
+The app has two modules, switched by the `训练` / `测试` tabs at the top:
+
+- `训练`: browse the cloud course list and do sentence-by-sentence playback
+  practice. The old built-in "示例课程" card was removed; only courses served
+  by `GET /api/v1/videos` appear here.
+- `测试`: record your reading of the current sentence and submit it to the
+  server's assessment endpoint for AI scoring. Only cloud courses are
+  supported (the server must know the video hash and reference sentences).
+
+The video's bottom-right corner has a small rotation icon that forces landscape
+or portrait orientation, so rotation works even when the device's auto-rotate
+switch is turned off. The progress bar below the sentence panel is draggable,
+so the student can seek to any position by dragging it.
+
+For the test module, fill in the client key that the server expects in the
+`X-Client-Key` header (the `CLIENT_API_KEY` value from the server's
+`sentence_api/.env`):
+
+```kotlin
+const val ASSESSMENT_API_KEY = "replace-with-your-client-api-key"
+```
+
+The app requests microphone permission at runtime on first use.
+
+### Troubleshooting "云端暂不可用"
+
+That label means `GET /api/v1/videos` failed. Since the fix, the sample app
+shows the underlying error next to the label (for example DNS resolution,
+timeout, TLS, or an unexpected HTTP status). Common causes:
+
+- The APK was built with the wrong `SERVER_BASE_URL` for your deployment.
+- The phone cannot reach the domain/IP (check with a browser on the phone, and
+  verify the server with `curl https://<server>/api/v1/videos`).
+- The gateway only exposes plain HTTP, so the app must use `http://...` instead
+  of `https://...`.
+- The server certificate is invalid/self-signed on the phone; use HTTP for
+  internal testing or install a valid certificate at the gateway.
+
 ## Local Video Testing
 
 The computer path `/Users/...` is not visible to an Android device. For a

android/oral-trainer-sdk/src/main/java/cn/learningpad/oraltrainer/sdk/HttpFallback.kt

@@ -0,0 +1,48 @@
+package cn.learningpad.oraltrainer.sdk
+
+import android.net.Uri
+import javax.net.ssl.SSLException
+
+/**
+ * Runs one blocking request against [baseUrl]. When [OralTrainerSdkConfig.allowHttpFallback]
+ * is enabled and the HTTPS attempt fails with a TLS error (broken certificates or
+ * misconfigured TLS termination at the gateway), retries the same request over plain HTTP.
+ * This is intended for private deployments; production should fix the TLS edge instead.
+ */
+internal class HttpFallback private constructor(
+    private val allowFallback: Boolean,
+) {
+    fun <T> execute(baseUrl: String, block: (String) -> T): T {
+        try {
+            return block(baseUrl)
+        } catch (error: Throwable) {
+            if (!allowFallback || !isTlsFailure(error)) {
+                throw error
+            }
+            val uri = Uri.parse(baseUrl)
+            if (uri.scheme != "https") {
+                throw error
+            }
+            val httpUrl = uri.buildUpon().scheme("http").build().toString()
+            return block(httpUrl)
+        }
+    }
+
+    private fun isTlsFailure(error: Throwable): Boolean {
+        var current: Throwable? = error
+        while (current != null) {
+            val message = current.message.orEmpty()
+            if (current is SSLException || message.contains("SSL", ignoreCase = true)) {
+                return true
+            }
+            current = current.cause
+        }
+        return false
+    }
+
+    companion object {
+        fun forConfig(config: OralTrainerSdkConfig): HttpFallback {
+            return HttpFallback(config.allowHttpFallback)
+        }
+    }
+}

android/oral-trainer-sdk/src/main/java/cn/learningpad/oraltrainer/sdk/OralTrainerController.kt

@@ -28,6 +28,8 @@ class OralTrainerController internal constructor(
     private val mainHandler = Handler(Looper.getMainLooper())
     private var released = false
     private var lastSentenceIndex: Int? = null
+    private var stopAtSentenceEnd = false
+    private var stopAtSentenceEndIndex: Int? = null
 
     var config: PlayerConfig = initialConfig
         private set
@@ -42,6 +44,7 @@ class OralTrainerController internal constructor(
             if (released) {
                 return
             }
+            enforceSentenceBoundary()
             notifySentenceIfChanged()
             notifySnapshot()
             mainHandler.postDelayed(this, 250L)
@@ -124,6 +127,8 @@ class OralTrainerController internal constructor(
         mediaItems.clear()
         mediaItems.addAll(items)
         lastSentenceIndex = null
+        stopAtSentenceEnd = false
+        stopAtSentenceEndIndex = null
         player.setMediaItems(items.map { it.toMedia3Item() }, safeIndex, max(0L, startPositionMs))
         player.prepare()
         player.playWhenReady = config.autoPlay
@@ -141,6 +146,8 @@ class OralTrainerController internal constructor(
     }
 
     fun pause() {
+        stopAtSentenceEnd = false
+        stopAtSentenceEndIndex = null
         player.pause()
     }
 
@@ -153,10 +160,14 @@ class OralTrainerController internal constructor(
     }
 
     fun stop() {
+        stopAtSentenceEnd = false
+        stopAtSentenceEndIndex = null
         player.stop()
     }
 
     fun seekTo(positionMs: Long) {
+        stopAtSentenceEnd = false
+        stopAtSentenceEndIndex = null
         player.seekTo(max(0L, positionMs))
     }
 
@@ -202,6 +213,18 @@ class OralTrainerController internal constructor(
         config = config.copy(sentenceMode = enabled)
     }
 
+    fun setContinuousPlayback(enabled: Boolean) {
+        config = config.copy(continuousPlayback = enabled)
+    }
+
+    fun playCurrentSentenceAndStop() {
+        val sentence = currentSentence() ?: return
+        player.seekTo(sentence.startMs)
+        stopAtSentenceEnd = true
+        stopAtSentenceEndIndex = sentence.index
+        player.play()
+    }
+
     fun currentTrainingItem(): TrainingMediaItem? {
         val index = player.currentMediaItemIndex
         return mediaItems.getOrNull(index)
@@ -335,6 +358,36 @@ class OralTrainerController internal constructor(
         listeners.forEach { it.onSentenceChanged(sentence) }
     }
 
+    private fun enforceSentenceBoundary() {
+        if (!config.sentenceMode || !player.isPlaying) {
+            return
+        }
+        val item = currentTrainingItem() ?: return
+        if (item.sentences.isEmpty()) {
+            return
+        }
+        val position = player.currentPosition
+        if (stopAtSentenceEnd) {
+            val index = stopAtSentenceEndIndex ?: return
+            val sentence = item.sentences.getOrNull(index) ?: return
+            if (position >= sentence.endMs) {
+                stopAtSentenceEnd = false
+                stopAtSentenceEndIndex = null
+                player.pause()
+                player.seekTo(sentence.startMs)
+            }
+            return
+        }
+        if (config.continuousPlayback) {
+            return
+        }
+        val anchorIndex = lastSentenceIndex ?: return
+        val anchor = item.sentences.getOrNull(anchorIndex) ?: return
+        if (position >= anchor.endMs) {
+            player.seekTo(anchor.startMs)
+        }
+    }
+
     private fun TrainingMediaItem.toMedia3Item(): MediaItem {
         val builder = MediaItem.Builder()
             .setMediaId(id)

android/oral-trainer-sdk/src/main/java/cn/learningpad/oraltrainer/sdk/OralTrainerSdkConfig.kt

@@ -10,4 +10,5 @@ data class OralTrainerSdkConfig @JvmOverloads constructor(
     val readTimeoutMs: Int = 30_000,
     val sentenceBoundaryApiBaseUrl: String = "https://videoservice.d1kt.cn",
     val assessmentApiKey: String? = null,
+    val allowHttpFallback: Boolean = false,
 )

android/oral-trainer-sdk/src/main/java/cn/learningpad/oraltrainer/sdk/PlayerConfig.kt

@@ -4,6 +4,7 @@ data class PlayerConfig @JvmOverloads constructor(
     val sentenceMode: Boolean = true,
     val defaultSeekStepMs: Long = 10_000L,
     val autoPlay: Boolean = false,
+    val continuousPlayback: Boolean = true,
     val minPlaybackSpeed: Float = 0.5f,
     val maxPlaybackSpeed: Float = 2.0f,
     val gestureControls: GestureControlsConfig = GestureControlsConfig(),

android/oral-trainer-sdk/src/main/java/cn/learningpad/oraltrainer/sdk/RemoteImitationQualityAssessor.kt

@@ -65,7 +65,8 @@ class RemoteImitationQualityAssessor internal constructor(
         require(SHA256_PATTERN.matches(videoHash)) {
             "ImitationAssessmentRequest.mediaId or metadata[video_hash] must be a SHA-256 hash."
         }
-        val endpoint = baseUri.buildUpon()
+        return HttpFallback.forConfig(config).execute(config.sentenceBoundaryApiBaseUrl) { effectiveBaseUrl ->
+            val endpoint = Uri.parse(effectiveBaseUrl).buildUpon()
                 .appendPath("api")
                 .appendPath("v1")
                 .appendPath("videos")
@@ -76,7 +77,7 @@ class RemoteImitationQualityAssessor internal constructor(
                 .build()
             val connection = URL(endpoint.toString()).openConnection() as HttpURLConnection
             val boundary = "----OralTrainer-${UUID.randomUUID()}"
-        return try {
+            try {
                 connection.requestMethod = "POST"
                 connection.doOutput = true
                 connection.connectTimeout = config.connectTimeoutMs
@@ -104,6 +105,7 @@ class RemoteImitationQualityAssessor internal constructor(
                 connection.disconnect()
             }
         }
+    }
 
     private fun writeFormField(output: BufferedOutputStream, boundary: String, name: String, value: String) {
         output.write("--$boundary\r\n".toByteArray(Charsets.UTF_8))

android/oral-trainer-sdk/src/main/java/cn/learningpad/oraltrainer/sdk/SentenceBoundaryApi.kt

@@ -98,7 +98,8 @@ class SentenceBoundaryApi internal constructor(
     }
 
     private fun fetchBlocking(videoHash: String): SentenceBoundaryApiResult {
-        val endpoint = baseUri.buildUpon()
+        return HttpFallback.forConfig(config).execute(config.sentenceBoundaryApiBaseUrl) { effectiveBaseUrl ->
+            val endpoint = Uri.parse(effectiveBaseUrl).buildUpon()
                 .appendPath("api")
                 .appendPath("v1")
                 .appendPath("videos")
@@ -106,7 +107,7 @@ class SentenceBoundaryApi internal constructor(
                 .appendPath("sentence-boundaries")
                 .build()
             val connection = URL(endpoint.toString()).openConnection() as HttpURLConnection
-        return try {
+            try {
                 connection.requestMethod = "GET"
                 connection.connectTimeout = config.connectTimeoutMs
                 connection.readTimeout = config.readTimeoutMs
@@ -127,6 +128,7 @@ class SentenceBoundaryApi internal constructor(
                 connection.disconnect()
             }
         }
+    }
 
     private fun parseResponse(
         body: String,

android/oral-trainer-sdk/src/main/java/cn/learningpad/oraltrainer/sdk/VideoCatalogApi.kt

@@ -44,7 +44,6 @@ class VideoCatalogApi internal constructor(
 ) {
     private val mainHandler = Handler(Looper.getMainLooper())
     private val executor: ExecutorService = Executors.newCachedThreadPool()
-    private val baseUrl = config.sentenceBoundaryApiBaseUrl.trimEnd('/') + "/"
 
     fun fetch(callback: VideoCatalogCallback): CancellableRequest {
         val future = executor.submit {
@@ -67,9 +66,10 @@ class VideoCatalogApi internal constructor(
     }
 
     private fun fetchBlocking(): List<TrainingVideoSummary> {
-        val endpoint = URL(URL(baseUrl), "api/v1/videos")
+        return HttpFallback.forConfig(config).execute(config.sentenceBoundaryApiBaseUrl) { effectiveBaseUrl ->
+            val endpoint = URL(URL(effectiveBaseUrl), "api/v1/videos")
             val connection = endpoint.openConnection() as HttpURLConnection
-        return try {
+            try {
                 connection.requestMethod = "GET"
                 connection.connectTimeout = config.connectTimeoutMs
                 connection.readTimeout = config.readTimeoutMs
@@ -79,25 +79,32 @@ class VideoCatalogApi internal constructor(
                 val stream = if (statusCode in 200..299) connection.inputStream else connection.errorStream
                 val body = stream?.bufferedReader(Charsets.UTF_8)?.use { it.readText() }.orEmpty()
                 if (statusCode !in 200..299) throw VideoCatalogApiException(statusCode, body)
-            parseResponse(body)
+                parseResponse(body, effectiveBaseUrl)
             } finally {
                 connection.disconnect()
             }
         }
+    }
 
-    private fun parseResponse(body: String): List<TrainingVideoSummary> {
+    private fun parseResponse(body: String, effectiveBaseUrl: String): List<TrainingVideoSummary> {
         val videos = JSONObject(body).getJSONArray("videos")
+        val effectiveScheme = Uri.parse(effectiveBaseUrl).scheme
         return buildList(videos.length()) {
             for (index in 0 until videos.length()) {
                 val item = videos.getJSONObject(index)
                 val status = item.getString("status")
                 if (status != "ready") continue
-                val streamUrl = URL(URL(baseUrl), item.getString("stream_url"))
+                val resolvedStreamUrl = URL(URL(effectiveBaseUrl), item.getString("stream_url")).toString()
+                val streamUri = if (effectiveScheme == "http") {
+                    Uri.parse(resolvedStreamUrl).buildUpon().scheme("http").build().toString()
+                } else {
+                    resolvedStreamUrl
+                }
                 add(
                     TrainingVideoSummary(
                         videoHash = item.getString("video_hash"),
                         title = item.getString("title"),
-                        streamUri = Uri.parse(streamUrl.toString()),
+                        streamUri = Uri.parse(streamUri),
                         durationMs = if (item.isNull("duration_ms")) null else item.getLong("duration_ms"),
                         sizeBytes = item.getLong("size_bytes"),
                         language = if (item.isNull("language")) null else item.getString("language"),

android/sample-app/src/main/AndroidManifest.xml

@@ -1,9 +1,11 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
     <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.RECORD_AUDIO" />
 
     <application
         android:allowBackup="true"
         android:label="@string/app_name"
+        android:networkSecurityConfig="@xml/network_security_config"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
         <activity

android/sample-app/src/main/java/cn/learningpad/oraltrainer/sample/MainActivity.kt

@@ -1,12 +1,18 @@
 package cn.learningpad.oraltrainer.sample
 
+import android.Manifest
 import android.app.Activity
 import android.content.Intent
+import android.content.pm.ActivityInfo
+import android.content.pm.PackageManager
 import android.content.res.ColorStateList
+import android.content.res.Configuration
 import android.graphics.Color
 import android.graphics.Typeface
 import android.graphics.drawable.GradientDrawable
+import android.media.MediaRecorder
 import android.net.Uri
+import android.os.Build
 import android.os.Bundle
 import android.view.Gravity
 import android.view.View
@@ -14,17 +20,22 @@ import android.view.ViewGroup
 import android.widget.Button
 import android.widget.FrameLayout
 import android.widget.HorizontalScrollView
+import android.widget.ImageButton
+import android.widget.ImageView
 import android.widget.LinearLayout
-import android.widget.ProgressBar
+import android.widget.SeekBar
+import android.widget.Switch
 import android.widget.TextView
-import androidx.media3.common.MimeTypes
 import cn.learningpad.oraltrainer.sdk.GestureEvent
 import cn.learningpad.oraltrainer.sdk.GestureKind
+import cn.learningpad.oraltrainer.sdk.ImitationAssessmentCallback
+import cn.learningpad.oraltrainer.sdk.ImitationAssessmentResult
 import cn.learningpad.oraltrainer.sdk.LoopMode
 import cn.learningpad.oraltrainer.sdk.OralTrainerController
 import cn.learningpad.oraltrainer.sdk.OralTrainerListener
 import cn.learningpad.oraltrainer.sdk.OralTrainerPlayerView
 import cn.learningpad.oraltrainer.sdk.OralTrainerSdk
+import cn.learningpad.oraltrainer.sdk.OralTrainerSdkConfig
 import cn.learningpad.oraltrainer.sdk.PlaybackSnapshot
 import cn.learningpad.oraltrainer.sdk.PlayerConfig
 import cn.learningpad.oraltrainer.sdk.SentenceBoundary
@@ -33,11 +44,13 @@ import cn.learningpad.oraltrainer.sdk.SentenceBoundaryApiResult
 import cn.learningpad.oraltrainer.sdk.TrainingMediaItem
 import cn.learningpad.oraltrainer.sdk.TrainingVideoSummary
 import cn.learningpad.oraltrainer.sdk.VideoCatalogCallback
+import java.io.File
 import java.util.Locale
 
 class MainActivity : Activity() {
     private lateinit var sdk: OralTrainerSdk
     private lateinit var controller: OralTrainerController
+    private lateinit var controllerListener: OralTrainerListener
     private lateinit var playerView: OralTrainerPlayerView
     private lateinit var lessonTitleText: TextView
     private lateinit var statusText: TextView
@@ -45,32 +58,78 @@ class MainActivity : Activity() {
     private lateinit var sentenceMetaText: TextView
     private lateinit var timeText: TextView
     private lateinit var speedText: TextView
-    private lateinit var progressBar: ProgressBar
+    private lateinit var progressBar: SeekBar
+    private var progressBarDragging = false
     private lateinit var catalogList: LinearLayout
     private lateinit var catalogStatusText: TextView
+    private lateinit var testStatusText: TextView
+    private lateinit var scoreSummaryText: TextView
+    private lateinit var scoreDetailText: TextView
+    private lateinit var recordButton: Button
+    private var mediaRecorder: MediaRecorder? = null
+    private var recordingFile: File? = null
 
-    private var activeItemId: String = SAMPLE_ID
+    private var activeItemId: String = ""
     private var currentSentenceCount = 0
     private var catalogVideos: List<TrainingVideoSummary> = emptyList()
+    private var catalogStatusTextValue = "正在同步"
+    private var activeModule = Module.TRAIN
+    private var continuousPlaybackEnabled = false
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         configureWindow()
 
-        sdk = OralTrainerSdk.init(this)
+        sdk = OralTrainerSdk.init(
+            this,
+            OralTrainerSdkConfig(
+                sentenceBoundaryApiBaseUrl = SERVER_BASE_URL,
+                assessmentApiKey = ASSESSMENT_API_KEY,
+                allowHttpFallback = true,
+            )
+        )
         controller = sdk.createController(
             playerConfig = PlayerConfig(
                 sentenceMode = true,
                 defaultSeekStepMs = 10_000L,
                 autoPlay = false,
-            )
+                continuousPlayback = false,
+            ),
+            imitationAssessor = sdk.createRemoteImitationQualityAssessor(),
         )
         controller.setLoopMode(LoopMode.ALL)
+        controllerListener = createControllerListener()
+        controller.addListener(controllerListener)
 
         setContentView(createContentView())
-        bindPlayerEvents()
-        loadSampleLesson()
         loadCatalog()
+        refreshCurrentUi()
+    }
+
+    override fun onConfigurationChanged(newConfig: Configuration) {
+        super.onConfigurationChanged(newConfig)
+        setContentView(createContentView())
+        renderCatalog()
+        refreshCurrentUi()
+        if (activeModule == Module.TEST) {
+            refreshTestUi()
+        }
+    }
+
+    override fun onRequestPermissionsResult(
+        requestCode: Int,
+        permissions: Array<out String>,
+        grantResults: IntArray,
+    ) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+        if (requestCode != RECORD_AUDIO_REQUEST) {
+            return
+        }
+        if (grantResults.firstOrNull() == PackageManager.PERMISSION_GRANTED) {
+            startRecording()
+        } else if (::testStatusText.isInitialized) {
+            testStatusText.text = "需要麦克风权限才能进行录音评测"
+        }
     }
 
     override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
@@ -122,6 +181,7 @@ class MainActivity : Activity() {
     }
 
     override fun onDestroy() {
+        discardRecording()
         controller.release()
         super.onDestroy()
     }
@@ -133,15 +193,119 @@ class MainActivity : Activity() {
     }
 
     private fun createContentView(): View {
+        val isLandscape = resources.configuration.orientation == Configuration.ORIENTATION_LANDSCAPE
+        return if (isLandscape) {
+            createLandscapeContentView()
+        } else {
+            createPortraitContentView()
+        }
+    }
+
+    private fun createPortraitContentView(): View {
         return LinearLayout(this).apply {
             orientation = LinearLayout.VERTICAL
             setBackgroundColor(COLOR_BACKGROUND)
+            addView(createModuleTabBar())
+            if (activeModule == Module.TEST) {
+                addView(createTestContentView())
+            } else {
                 addView(createHeader())
                 addView(createPlayerSection())
                 addView(createSentenceSection())
                 addView(createCatalogSection())
             }
         }
+    }
+
+    private fun createTestContentView(): View {
+        return LinearLayout(this).apply {
+            orientation = LinearLayout.VERTICAL
+            setBackgroundColor(COLOR_BACKGROUND)
+            addView(createPlayerSection())
+            addView(createSentenceSection())
+            addView(createTestSection())
+        }
+    }
+
+    private fun createModuleTabBar(): View {
+        return LinearLayout(this).apply {
+            orientation = LinearLayout.HORIZONTAL
+            setPadding(16.dp, 40.dp, 16.dp, 0)
+            addView(moduleTab("训练", Module.TRAIN))
+            addView(moduleTab("测试", Module.TEST))
+        }
+    }
+
+    private fun moduleTab(label: String, module: Module): TextView {
+        val selected = activeModule == module
+        return TextView(this).apply {
+            text = label
+            textSize = 15f
+            typeface = Typeface.DEFAULT_BOLD
+            gravity = Gravity.CENTER
+            isClickable = true
+            setTextColor(if (selected) Color.WHITE else COLOR_TEXT_MUTED)
+            background = if (selected) {
+                rounded(COLOR_BUTTON, 8f)
+            } else {
+                rounded(COLOR_SURFACE, 8f, COLOR_BORDER)
+            }
+            layoutParams = LinearLayout.LayoutParams(0, 44.dp, 1f).withMargins(0, 0, 8.dp, 0)
+            setOnClickListener {
+                if (activeModule == module) {
+                    return@setOnClickListener
+                }
+                if (activeModule == Module.TEST) {
+                    discardRecording()
+                }
+                activeModule = module
+                controller.setContinuousPlayback(
+                    if (activeModule == Module.TRAIN) continuousPlaybackEnabled else true
+                )
+                setContentView(createContentView())
+                renderCatalog()
+                refreshCurrentUi()
+                if (activeModule == Module.TEST) {
+                    refreshTestUi()
+                }
+            }
+        }
+    }
+
+    private fun createLandscapeContentView(): View {
+        return FrameLayout(this).apply {
+            setBackgroundColor(Color.BLACK)
+            addView(createPlayerView())
+            addView(createPlayerOverlay())
+            addView(
+                LinearLayout(this@MainActivity).apply {
+                    orientation = LinearLayout.VERTICAL
+                    layoutParams = FrameLayout.LayoutParams(
+                        ViewGroup.LayoutParams.MATCH_PARENT,
+                        ViewGroup.LayoutParams.WRAP_CONTENT,
+                        Gravity.BOTTOM,
+                    )
+                    addView(createLandscapeSentencePanel().apply {
+                        layoutParams = LinearLayout.LayoutParams(
+                            ViewGroup.LayoutParams.MATCH_PARENT,
+                            ViewGroup.LayoutParams.WRAP_CONTENT,
+                        )
+                    })
+                    addView(createRotationButtonRow())
+                }
+            )
+        }
+    }
+
+    private fun createLandscapeSentencePanel(): View {
+        return createSentenceContent(translucent = true).apply {
+            layoutParams = FrameLayout.LayoutParams(
+                ViewGroup.LayoutParams.MATCH_PARENT,
+                ViewGroup.LayoutParams.WRAP_CONTENT,
+                Gravity.BOTTOM,
+            )
+        }
+    }
 
     private fun createHeader(): View {
         val titleBlock = LinearLayout(this).apply {
@@ -149,16 +313,16 @@ class MainActivity : Activity() {
             gravity = Gravity.CENTER_VERTICAL
             layoutParams = LinearLayout.LayoutParams(0, ViewGroup.LayoutParams.WRAP_CONTENT, 1f)
             addView(TextView(this@MainActivity).apply {
-                text = "口语宝"
+                text = "跟读虫"
                 setTextColor(Color.WHITE)
-                textSize = 26f
+                textSize = 32f
                 typeface = Typeface.DEFAULT_BOLD
                 includeFontPadding = false
             })
             addView(TextView(this@MainActivity).apply {
-                text = "中英跟读训练"
+                text = "外语跟读训练神器"
                 setTextColor(COLOR_TEXT_MUTED)
-                textSize = 13f
+                textSize = 20f
                 setPadding(1.dp, 4.dp, 0, 0)
             })
         }
@@ -174,14 +338,40 @@ class MainActivity : Activity() {
     }
 
     private fun createPlayerSection(): View {
-        playerView = OralTrainerPlayerView(this).apply {
+        return FrameLayout(this).apply {
+            background = rounded(COLOR_SURFACE, 8f, COLOR_BORDER)
+            clipToOutline = true
+            layoutParams = LinearLayout.LayoutParams(
+                ViewGroup.LayoutParams.MATCH_PARENT,
+                0,
+                1f,
+            ).withMargins(16.dp, 0, 16.dp, 10.dp)
+            addView(createPlayerView())
+            addView(createPlayerOverlay())
+            addView(createRotationButton().apply {
+                layoutParams = FrameLayout.LayoutParams(
+                    44.dp,
+                    44.dp,
+                    Gravity.BOTTOM or Gravity.END,
+                ).apply {
+                    marginEnd = 12.dp
+                    bottomMargin = 12.dp
+                }
+            })
+        }
+    }
+
+    private fun createPlayerView(): OralTrainerPlayerView {
+        return OralTrainerPlayerView(this).apply {
             bind(controller)
             layoutParams = FrameLayout.LayoutParams(
                 ViewGroup.LayoutParams.MATCH_PARENT,
                 ViewGroup.LayoutParams.MATCH_PARENT,
             )
+        }.also { playerView = it }
     }
 
+    private fun createPlayerOverlay(): View {
         val overlay = LinearLayout(this).apply {
             orientation = LinearLayout.HORIZONTAL
             gravity = Gravity.CENTER_VERTICAL
@@ -192,71 +382,123 @@ class MainActivity : Activity() {
                 Gravity.TOP,
             )
         }
-
         timeText = overlayPill("--:-- / --:--").apply {
             layoutParams = LinearLayout.LayoutParams(0, ViewGroup.LayoutParams.WRAP_CONTENT, 1f)
         }
         speedText = overlayPill("1x")
         overlay.addView(timeText)
         overlay.addView(speedText)
+        return overlay
+    }
 
-        return FrameLayout(this).apply {
+    private fun createRotationButtonRow(): View {
-            background = rounded(COLOR_SURFACE, 8f, COLOR_BORDER)
+        return LinearLayout(this).apply {
-            clipToOutline = true
+            orientation = LinearLayout.HORIZONTAL
-            layoutParams = LinearLayout.LayoutParams(
+            gravity = Gravity.END
-                ViewGroup.LayoutParams.MATCH_PARENT,
+            setPadding(0, 0, 12.dp, 12.dp)
-                0,
+            addView(createRotationButton())
-                1f,
+        }
-            ).withMargins(16.dp, 0, 16.dp, 10.dp)
+    }
-            addView(playerView)
+
-            addView(overlay)
+    private fun createRotationButton(): ImageButton {
+        val isLandscape = resources.configuration.orientation == Configuration.ORIENTATION_LANDSCAPE
+        return ImageButton(this).apply {
+            setImageResource(R.drawable.ic_screen_rotation)
+            imageTintList = ColorStateList.valueOf(Color.WHITE)
+            background = rounded(Color.argb(178, 9, 12, 16), 22.dp.toFloat())
+            scaleType = ImageView.ScaleType.CENTER_INSIDE
+            setPadding(10.dp, 10.dp, 10.dp, 10.dp)
+            contentDescription = if (isLandscape) "竖屏" else "横屏"
+            layoutParams = LinearLayout.LayoutParams(44.dp, 44.dp)
+            setOnClickListener { toggleOrientation() }
+        }
+    }
+
+    private fun toggleOrientation() {
+        val isLandscape = resources.configuration.orientation == Configuration.ORIENTATION_LANDSCAPE
+        requestedOrientation = if (isLandscape) {
+            ActivityInfo.SCREEN_ORIENTATION_PORTRAIT
+        } else {
+            ActivityInfo.SCREEN_ORIENTATION_SENSOR_LANDSCAPE
         }
     }
 
     private fun createSentenceSection(): View {
-        lessonTitleText = TextView(this).apply {
+        return createSentenceContent(translucent = false).apply {
-            setTextColor(COLOR_TEXT_DARK)
-            textSize = 17f
-            typeface = Typeface.DEFAULT_BOLD
-            maxLines = 1
-        }
-        sentenceMetaText = TextView(this).apply {
-            setTextColor(COLOR_ACCENT_DEEP)
-            textSize = 13f
-            setPadding(0, 8.dp, 0, 0)
-        }
-        sentenceText = TextView(this).apply {
-            setTextColor(COLOR_TEXT_DARK)
-            textSize = 22f
-            typeface = Typeface.DEFAULT_BOLD
-            setLineSpacing(2.dp.toFloat(), 1.05f)
-            setPadding(0, 10.dp, 0, 10.dp)
-        }
-        progressBar = ProgressBar(this, null, android.R.attr.progressBarStyleHorizontal).apply {
-            max = PROGRESS_MAX
-            progress = 0
-            progressTintList = ColorStateList.valueOf(COLOR_ACCENT)
-            progressBackgroundTintList = ColorStateList.valueOf(COLOR_PROGRESS_TRACK)
-            layoutParams = LinearLayout.LayoutParams(
-                ViewGroup.LayoutParams.MATCH_PARENT,
-                6.dp,
-            )
-        }
-        statusText = TextView(this).apply {
-            setTextColor(COLOR_TEXT_SUBTLE)
-            textSize = 13f
-            setPadding(0, 10.dp, 0, 0)
-        }
-
-        return LinearLayout(this).apply {
-            orientation = LinearLayout.VERTICAL
             background = rounded(Color.WHITE, 8f, COLOR_LIGHT_BORDER)
             setPadding(18.dp, 16.dp, 18.dp, 16.dp)
             layoutParams = LinearLayout.LayoutParams(
                 ViewGroup.LayoutParams.MATCH_PARENT,
                 ViewGroup.LayoutParams.WRAP_CONTENT,
             ).withMargins(16.dp, 0, 16.dp, 12.dp)
+        }
+    }
+
+    private fun createSentenceContent(translucent: Boolean): LinearLayout {
+        lessonTitleText = TextView(this).apply {
+            setTextColor(if (translucent) Color.WHITE else COLOR_TEXT_DARK)
+            textSize = 17f
+            typeface = Typeface.DEFAULT_BOLD
+            maxLines = 1
+        }
+        sentenceMetaText = TextView(this).apply {
+            setTextColor(if (translucent) COLOR_ACCENT_LIGHT else COLOR_ACCENT_DEEP)
+            textSize = 13f
+            setPadding(0, 8.dp, 0, 0)
+        }
+        sentenceText = TextView(this).apply {
+            setTextColor(if (translucent) Color.WHITE else COLOR_TEXT_DARK)
+            textSize = 22f
+            typeface = Typeface.DEFAULT_BOLD
+            setLineSpacing(2.dp.toFloat(), 1.05f)
+            setPadding(0, 10.dp, 0, 10.dp)
+        }
+        progressBar = SeekBar(this).apply {
+            max = PROGRESS_MAX
+            progress = 0
+            progressTintList = ColorStateList.valueOf(COLOR_ACCENT)
+            progressBackgroundTintList = ColorStateList.valueOf(
+                if (translucent) COLOR_PROGRESS_TRACK_DARK else COLOR_PROGRESS_TRACK
+            )
+            thumbTintList = ColorStateList.valueOf(COLOR_ACCENT)
+            layoutParams = LinearLayout.LayoutParams(
+                ViewGroup.LayoutParams.MATCH_PARENT,
+                28.dp,
+            )
+            setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener {
+                override fun onProgressChanged(seekBar: SeekBar, progress: Int, fromUser: Boolean) {
+                    if (fromUser) {
+                        val duration = controller.snapshot().durationMs
+                        timeText.text = "${formatTime(seekPositionForProgress(progress))} / ${formatTime(duration)}"
+                    }
+                }
+
+                override fun onStartTrackingTouch(seekBar: SeekBar) {
+                    progressBarDragging = true
+                }
+
+                override fun onStopTrackingTouch(seekBar: SeekBar) {
+                    progressBarDragging = false
+                    controller.seekTo(seekPositionForProgress(seekBar.progress))
+                }
+            })
+        }
+        statusText = TextView(this).apply {
+            setTextColor(if (translucent) COLOR_TEXT_OVERLAY else COLOR_TEXT_SUBTLE)
+            textSize = 13f
+            setPadding(0, 10.dp, 0, 0)
+        }
+
+        return LinearLayout(this).apply {
+            orientation = LinearLayout.VERTICAL
+            if (translucent) {
+                background = rounded(COLOR_OVERLAY, 0f, null)
+                setPadding(18.dp, 14.dp, 18.dp, 16.dp)
+            }
             addView(lessonTitleText)
+            if (activeModule == Module.TRAIN) {
+                addView(createContinuousPlaybackRow(translucent))
+            }
             addView(sentenceMetaText)
             addView(sentenceText)
             addView(progressBar)
@@ -264,6 +506,36 @@ class MainActivity : Activity() {
         }
     }
 
+    private fun createContinuousPlaybackRow(translucent: Boolean): View {
+        return LinearLayout(this).apply {
+            orientation = LinearLayout.HORIZONTAL
+            gravity = Gravity.CENTER_VERTICAL
+            setPadding(0, 6.dp, 0, 0)
+            addView(TextView(this@MainActivity).apply {
+                text = "连续播放"
+                setTextColor(if (translucent) COLOR_TEXT_OVERLAY else COLOR_TEXT_SUBTLE)
+                textSize = 13f
+                typeface = Typeface.DEFAULT_BOLD
+                layoutParams = LinearLayout.LayoutParams(0, ViewGroup.LayoutParams.WRAP_CONTENT, 1f)
+            })
+            addView(Switch(this@MainActivity).apply {
+                isChecked = continuousPlaybackEnabled
+                buttonTintList = ColorStateList.valueOf(
+                    if (translucent) COLOR_ACCENT_LIGHT else COLOR_ACCENT
+                )
+                setOnCheckedChangeListener { _, checked ->
+                    continuousPlaybackEnabled = checked
+                    controller.setContinuousPlayback(checked)
+                    statusText.text = if (checked) {
+                        "已开启连续播放，将按句子顺序连续播放"
+                    } else {
+                        "已关闭连续播放，将循环播放当前句子"
+                    }
+                }
+            })
+        }
+    }
+
     private fun createCatalogSection(): View {
         catalogStatusText = TextView(this).apply {
             setTextColor(COLOR_TEXT_MUTED)
@@ -302,13 +574,243 @@ class MainActivity : Activity() {
         }
     }
 
-    private fun bindPlayerEvents() {
+    private fun createTestSection(): View {
-        controller.addListener(object : OralTrainerListener {
+        testStatusText = TextView(this).apply {
+            setTextColor(COLOR_ACCENT_DEEP)
+            textSize = 13f
+            setPadding(0, 0, 0, 8.dp)
+        }
+        scoreSummaryText = TextView(this).apply {
+            setTextColor(COLOR_TEXT_DARK)
+            textSize = 22f
+            typeface = Typeface.DEFAULT_BOLD
+            setPadding(0, 8.dp, 0, 0)
+            text = "尚未评测"
+        }
+        scoreDetailText = TextView(this).apply {
+            setTextColor(COLOR_TEXT_SUBTLE)
+            textSize = 13f
+            setLineSpacing(4.dp.toFloat(), 1f)
+            setPadding(0, 8.dp, 0, 0)
+        }
+
+        val sentenceButton = { label: String, action: () -> Unit ->
+            Button(this).apply {
+                text = label
+                isAllCaps = false
+                setTextColor(Color.WHITE)
+                textSize = 13f
+                typeface = Typeface.DEFAULT_BOLD
+                minWidth = 0
+                minHeight = 0
+                minimumWidth = 0
+                minimumHeight = 0
+                setPadding(0, 0, 0, 0)
+                background = rounded(COLOR_BUTTON, 8f)
+                layoutParams = LinearLayout.LayoutParams(0, 40.dp, 1f).withMargins(0, 0, 8.dp, 0)
+                setOnClickListener { action() }
+            }
+        }
+
+        recordButton = Button(this).apply {
+            text = "开始录音"
+            isAllCaps = false
+            setTextColor(Color.WHITE)
+            textSize = 14f
+            typeface = Typeface.DEFAULT_BOLD
+            minWidth = 0
+            minHeight = 0
+            minimumWidth = 0
+            minimumHeight = 0
+            background = rounded(COLOR_ACCENT, 8f)
+            layoutParams = LinearLayout.LayoutParams(
+                ViewGroup.LayoutParams.MATCH_PARENT,
+                44.dp,
+            )
+            setOnClickListener {
+                if (mediaRecorder == null) {
+                    startRecording()
+                } else {
+                    stopRecordingAndAssess()
+                }
+            }
+        }
+
+        val controlRow = LinearLayout(this).apply {
+            orientation = LinearLayout.HORIZONTAL
+            addView(sentenceButton("上一句") { controller.seekToPreviousSentence() })
+            addView(sentenceButton("播放原句") {
+                controller.playCurrentSentenceAndStop()
+                statusText.text = "正在播放当前句子，播放完自动停止"
+            })
+            addView(sentenceButton("下一句") { controller.seekToNextSentence() })
+        }
+
+        return LinearLayout(this).apply {
+            orientation = LinearLayout.VERTICAL
+            background = rounded(Color.WHITE, 8f, COLOR_LIGHT_BORDER)
+            setPadding(18.dp, 14.dp, 18.dp, 16.dp)
+            layoutParams = LinearLayout.LayoutParams(
+                ViewGroup.LayoutParams.MATCH_PARENT,
+                ViewGroup.LayoutParams.WRAP_CONTENT,
+            ).withMargins(16.dp, 0, 16.dp, 12.dp)
+            addView(TextView(this@MainActivity).apply {
+                text = "朗读评测（测试）"
+                setTextColor(COLOR_TEXT_DARK)
+                textSize = 16f
+                typeface = Typeface.DEFAULT_BOLD
+            })
+            addView(testStatusText)
+            addView(controlRow)
+            addView(recordButton)
+            addView(scoreSummaryText)
+            addView(scoreDetailText)
+        }
+    }
+
+    private fun refreshTestUi() {
+        if (!::testStatusText.isInitialized) {
+            return
+        }
+        recordButton.text = if (mediaRecorder == null) "开始录音" else "停止并评测"
+        val item = controller.currentTrainingItem()
+        val sentence = controller.currentSentence()
+        testStatusText.text = if (item == null || sentence == null) {
+            "请先在训练模块选择一个云端课程"
+        } else {
+            "评测对象：第 ${sentence.index + 1} 句（共 ${item.sentences.size} 句）"
+        }
+    }
+
+    private fun startRecording() {
+        controller.pause()
+        if (!::testStatusText.isInitialized) {
+            return
+        }
+        if (checkSelfPermission(Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED) {
+            requestPermissions(arrayOf(Manifest.permission.RECORD_AUDIO), RECORD_AUDIO_REQUEST)
+            return
+        }
+        val file = File(cacheDir, "attempt-${System.currentTimeMillis()}.m4a")
+        val recorder = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
+            MediaRecorder(this)
+        } else {
+            @Suppress("DEPRECATION")
+            MediaRecorder()
+        }
+        try {
+            recorder.setAudioSource(MediaRecorder.AudioSource.MIC)
+            recorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4)
+            recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC)
+            recorder.setAudioSamplingRate(16_000)
+            recorder.setAudioEncodingBitRate(96_000)
+            recorder.setOutputFile(file.absolutePath)
+            recorder.prepare()
+            recorder.start()
+            mediaRecorder = recorder
+            recordingFile = file
+            recordButton.text = "停止并评测"
+            testStatusText.text = "正在录音…读完当前句子后点击“停止并评测”"
+        } catch (error: Throwable) {
+            testStatusText.text = "录音启动失败：${error.message.orEmpty()}"
+            runCatching { recorder.release() }
+        }
+    }
+
+    private fun stopRecordingAndAssess() {
+        val recorder = mediaRecorder ?: return
+        val file = recordingFile ?: return
+        mediaRecorder = null
+        recordButton.text = "开始录音"
+        try {
+            recorder.stop()
+        } catch (error: Throwable) {
+            testStatusText.text = "录音太短或无法保存：${error.message.orEmpty()}"
+            file.delete()
+            recordingFile = null
+            return
+        } finally {
+            runCatching { recorder.release() }
+        }
+        recordingFile = null
+        submitAssessment(Uri.fromFile(file))
+    }
+
+    private fun discardRecording() {
+        val recorder = mediaRecorder ?: return
+        mediaRecorder = null
+        runCatching { recorder.stop() }
+        runCatching { recorder.release() }
+        recordingFile?.delete()
+        recordingFile = null
+    }
+
+    private fun submitAssessment(recordingUri: Uri) {
+        val item = controller.currentTrainingItem()
+        val sentence = controller.currentSentence()
+        if (item == null || sentence == null) {
+            testStatusText.text = "没有正在学习的句子，无法评测"
+            return
+        }
+        if (!SHA256_PATTERN.matches(item.id)) {
+            testStatusText.text = "仅云端课程支持朗读评测（本地视频请先上传到服务器）"
+            return
+        }
+        if (ASSESSMENT_API_KEY.isBlank() || ASSESSMENT_API_KEY.startsWith("replace-")) {
+            testStatusText.text = "未配置评分密钥：请在 MainActivity 填入服务器 .env 的 CLIENT_API_KEY"
+            return
+        }
+        testStatusText.text = "正在评测第 ${sentence.index + 1} 句，请稍候…"
+        scoreSummaryText.text = "评测中…"
+        scoreDetailText.text = ""
+        controller.assessCurrentSentence(
+            recordingUri = recordingUri,
+            locale = sentence.language
+                ?.takeIf { it.isNotBlank() }
+                ?: item.sentences.getOrNull(sentence.index)?.language,
+            metadata = mapOf("video_hash" to item.id),
+            callback = object : ImitationAssessmentCallback {
+                override fun onResult(result: ImitationAssessmentResult) {
+                    if (::testStatusText.isInitialized) {
+                        applyAssessmentResult(result)
+                    }
+                }
+
+                override fun onError(error: Throwable) {
+                    if (::testStatusText.isInitialized) {
+                        testStatusText.text = "评测失败：${error.message.orEmpty()}"
+                        scoreSummaryText.text = "评测失败"
+                    }
+                }
+            },
+        )
+    }
+
+    private fun applyAssessmentResult(result: ImitationAssessmentResult) {
+        testStatusText.text = if (result.passed == true) "已通过" else "未通过"
+        scoreSummaryText.text = String.format(Locale.US, "总分 %.1f", result.overallScore)
+        scoreDetailText.text = buildString {
+            result.contentScore?.let { appendLine(String.format(Locale.US, "内容分 %.1f", it)) }
+            result.fluencyScore?.let { appendLine(String.format(Locale.US, "流畅度 %.1f", it)) }
+            result.durationScore?.let { appendLine(String.format(Locale.US, "时长分 %.1f", it)) }
+            result.pauseScore?.let { appendLine(String.format(Locale.US, "停顿分 %.1f", it)) }
+            result.speechRateScore?.let { appendLine(String.format(Locale.US, "语速分 %.1f", it)) }
+            result.referenceText?.let { appendLine("参考：$it") }
+            result.recognizedText?.let { appendLine("识别：$it") }
+            if (result.missingTokens.isNotEmpty()) {
+                appendLine("漏读：${result.missingTokens.joinToString("、")}")
+            }
+            if (result.extraTokens.isNotEmpty()) {
+                appendLine("多读：${result.extraTokens.joinToString("、")}")
+            }
+            result.feedback?.let { appendLine(it) }
+        }.trimEnd()
+    }
+
+    private fun createControllerListener(): OralTrainerListener {
+        return object : OralTrainerListener {
             override fun onPlaybackSnapshot(snapshot: PlaybackSnapshot) {
-                timeText.text = "${formatTime(snapshot.positionMs)} / ${formatTime(snapshot.durationMs)}"
+                applyPlaybackSnapshot(snapshot)
-                speedText.text = formatSpeed(snapshot.playbackSpeed)
-                statusText.text = playbackStatus(snapshot)
-                progressBar.progress = playbackProgress(snapshot)
             }
 
             override fun onMediaChanged(item: TrainingMediaItem?) {
@@ -317,18 +819,7 @@ class MainActivity : Activity() {
             }
 
             override fun onSentenceChanged(sentence: SentenceBoundary?) {
-                if (sentence == null) {
+                applySentence(sentence)
-                    sentenceMetaText.text = "暂无句子边界"
-                    sentenceText.text = lessonTitleText.text
-                    return
-                }
-                val countText = if (currentSentenceCount > 0) {
-                    " / $currentSentenceCount"
-                } else {
-                    ""
-                }
-                sentenceMetaText.text = "第 ${sentence.index + 1}$countText 句  ${formatTime(sentence.startMs)}-${formatTime(sentence.endMs)}"
-                sentenceText.text = sentence.text?.takeIf { it.isNotBlank() } ?: "当前句子"
             }
 
             override fun onGesture(event: GestureEvent) {
@@ -343,33 +834,76 @@ class MainActivity : Activity() {
             override fun onPlayerError(error: Throwable) {
                 statusText.text = "播放失败：${error.message.orEmpty()}"
             }
-        })
+        }
     }
 
-    private fun loadSampleLesson() {
+    private fun applyPlaybackSnapshot(snapshot: PlaybackSnapshot) {
-        val item = sampleOnlineLesson()
+        if (!progressBarDragging) {
-        activeItemId = item.id
+            timeText.text = "${formatTime(snapshot.positionMs)} / ${formatTime(snapshot.durationMs)}"
-        currentSentenceCount = item.sentences.size
+            progressBar.progress = playbackProgress(snapshot)
-        controller.loadItem(item)
+        }
-        lessonTitleText.text = item.title
+        speedText.text = formatSpeed(snapshot.playbackSpeed)
-        renderCatalog()
+        statusText.text = playbackStatus(snapshot)
+    }
+
+    private fun seekPositionForProgress(progress: Int): Long {
+        val duration = controller.snapshot().durationMs
+        if (duration <= 0L) {
+            return 0L
+        }
+        return progress.toLong() * duration / PROGRESS_MAX
+    }
+
+    private fun applySentence(sentence: SentenceBoundary?) {
+        if (sentence == null) {
+            sentenceMetaText.text = "暂无句子边界"
+            sentenceText.text = lessonTitleText.text
+            return
+        }
+        val countText = if (currentSentenceCount > 0) {
+            " / $currentSentenceCount"
+        } else {
+            ""
+        }
+        sentenceMetaText.text = "第 ${sentence.index + 1}$countText 句  ${formatTime(sentence.startMs)}-${formatTime(sentence.endMs)}"
+        sentenceText.text = sentence.text?.takeIf { it.isNotBlank() } ?: "当前句子"
+    }
+
+    private fun refreshCurrentUi() {
+        val item = controller.currentTrainingItem()
+        lessonTitleText.text = item?.title ?: "未选择课程"
+        currentSentenceCount = item?.sentences?.size ?: 0
+        applyPlaybackSnapshot(controller.snapshot())
+        applySentence(controller.currentSentence())
+        if (::catalogStatusText.isInitialized) {
+            catalogStatusText.text = catalogStatusTextValue
+        }
     }
 
     private fun loadCatalog() {
-        catalogStatusText.text = "正在同步"
+        catalogStatusTextValue = "正在同步"
+        if (::catalogStatusText.isInitialized) {
+            catalogStatusText.text = catalogStatusTextValue
+        }
         sdk.videoCatalogApi.fetch(object : VideoCatalogCallback {
             override fun onSuccess(videos: List<TrainingVideoSummary>) {
                 catalogVideos = videos
-                catalogStatusText.text = if (videos.isEmpty()) {
+                catalogStatusTextValue = if (videos.isEmpty()) {
                     "暂无云端课程"
                 } else {
                     "${videos.size} 个云端课程"
                 }
+                if (::catalogStatusText.isInitialized) {
+                    catalogStatusText.text = catalogStatusTextValue
+                }
                 renderCatalog()
             }
 
             override fun onError(error: Throwable) {
-                catalogStatusText.text = "云端暂不可用"
+                catalogStatusTextValue = "云端暂不可用：${error.message.orEmpty()}"
+                if (::catalogStatusText.isInitialized) {
+                    catalogStatusText.text = catalogStatusTextValue
+                }
                 renderCatalog()
             }
         })
@@ -380,15 +914,6 @@ class MainActivity : Activity() {
             return
         }
         catalogList.removeAllViews()
-        catalogList.addView(
-            videoCard(
-                id = SAMPLE_ID,
-                title = "示例课程",
-                meta = "4 句 · ${formatTime(16_000L)}",
-            ) {
-                loadSampleLesson()
-            }
-        )
         catalogVideos.forEach { video ->
             catalogList.addView(
                 videoCard(
@@ -516,22 +1041,6 @@ class MainActivity : Activity() {
         )
     }
 
-    private fun sampleOnlineLesson(): TrainingMediaItem {
-        return TrainingMediaItem(
-            id = SAMPLE_ID,
-            title = "口语宝示例课",
-            uri = Uri.parse("https://storage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4"),
-            mimeType = MimeTypes.VIDEO_MP4,
-            customCacheKey = SAMPLE_ID,
-            sentences = listOf(
-                SentenceBoundary(0, 0L, 3_000L, "Good morning, everyone."),
-                SentenceBoundary(1, 3_000L, 7_000L, "Today we will practice listening carefully."),
-                SentenceBoundary(2, 7_000L, 11_000L, "Please repeat each sentence clearly."),
-                SentenceBoundary(3, 11_000L, 16_000L, "Small daily practice makes progress visible."),
-            ),
-        )
-    }
-
     private fun playbackStatus(snapshot: PlaybackSnapshot): String {
         val state = when {
             snapshot.isPlaying -> "播放中"
@@ -599,22 +1108,38 @@ class MainActivity : Activity() {
         get() = (this * resources.displayMetrics.density).toInt()
 
     private companion object {
+        // 服务端地址：改成你实际部署的域名或 IP。
+        // 内网/开发环境可填 http://<服务器IP>:<端口>（例如 http://192.168.1.100:80）。
+        const val SERVER_BASE_URL = "https://videoservice.d1kt.cn"
+        // 朗读评测密钥：填服务器 sentence_api/.env 里的 CLIENT_API_KEY。
+        const val ASSESSMENT_API_KEY = "fcf60fa10bc1c49e5ddb93d570bc54df5648e187b64096962498d57661c14220"
+
         const val PICK_VIDEO_REQUEST = 1001
-        const val SAMPLE_ID = "online_sample_01"
+        const val RECORD_AUDIO_REQUEST = 1002
         const val PROGRESS_MAX = 1000
 
+        private val SHA256_PATTERN = Regex("^[0-9a-fA-F]{64}$")
+
+        enum class Module {
+            TRAIN,
+            TEST,
+        }
+
         val COLOR_BACKGROUND: Int = Color.rgb(12, 15, 18)
         val COLOR_SURFACE: Int = Color.rgb(28, 34, 40)
         val COLOR_BORDER: Int = Color.rgb(50, 59, 67)
         val COLOR_BUTTON: Int = Color.rgb(37, 99, 235)
         val COLOR_ACCENT: Int = Color.rgb(21, 184, 132)
         val COLOR_ACCENT_DEEP: Int = Color.rgb(7, 118, 86)
+        val COLOR_ACCENT_LIGHT: Int = Color.rgb(94, 234, 182)
         val COLOR_SELECTED: Int = Color.rgb(229, 248, 240)
         val COLOR_PROGRESS_TRACK: Int = Color.rgb(224, 231, 235)
+        val COLOR_PROGRESS_TRACK_DARK: Int = Color.rgb(55, 62, 70)
         val COLOR_LIGHT_BORDER: Int = Color.rgb(218, 226, 232)
         val COLOR_OVERLAY: Int = Color.argb(178, 9, 12, 16)
         val COLOR_TEXT_DARK: Int = Color.rgb(18, 24, 31)
         val COLOR_TEXT_MUTED: Int = Color.rgb(151, 162, 174)
         val COLOR_TEXT_SUBTLE: Int = Color.rgb(88, 98, 108)
+        val COLOR_TEXT_OVERLAY: Int = Color.rgb(163, 172, 182)
     }
 }

android/sample-app/src/main/res/drawable/ic_screen_rotation.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24.0"
+    android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FFFFFFFF"
+        android:pathData="M16.48,2.52c3,2.02 5.02,5.27 5.02,9.48 0,1.77 -0.38,3.45 -1.06,4.97L10.02,2.94C11.39,2.51 12.86,2.28 14.4,2.28c0.74,0 1.47,0.08 2.08,0.24zM10.02,21.06L1.56,7.43C0.56,8.82 0,10.36 0,12c0,4.97 4.03,9 9,9h0.51C9.73,21.06 9.87,21.06 10.02,21.06zM9,22.06C3.96,22.06 -0.03,18.08 -0.03,13.04c0,-1.6 0.39,-3.11 1.07,-4.44l8.57,13.12C9.63,21.72 9.6,21.88 9.6,22.06 9.6,22.06 9.6,22.06 9,22.06zM20.93,5.44c0.68,1.33 1.07,2.84 1.07,4.44 0,5.04 -3.99,9.02 -9.03,9.02 -0.2,0 -0.4,-0.01 -0.6,-0.02l8.56,-13.44L20.93,5.44z"/>
+</vector>

android/sample-app/src/main/res/values/strings.xml

@@ -1,3 +1,3 @@
 <resources>
-    <string name="app_name">口语宝</string>
+    <string name="app_name">跟读虫</string>
 </resources>

android/sample-app/src/main/res/xml/network_security_config.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+    允许 HTTP 明文访问，便于直连内网/开发环境部署的服务器（如 http://192.168.x.x）。
+    同时信任系统证书和用户手动安装的证书（自签/私有 CA 时需先把证书装到手机）。
+-->
+<network-security-config>
+    <base-config cleartextTrafficPermitted="true">
+        <trust-anchors>
+            <certificates src="system" />
+            <certificates src="user" />
+        </trust-anchors>
+    </base-config>
+</network-security-config>

sentence_api/DEPLOYMENT.md

@@ -286,6 +286,84 @@ https://videoservice.d1kt.cn/admin
 不要硬编码进公开代码仓库。SDK 会在评分请求中发送 `X-Client-Key`。公开视频列表和播放
 接口仍可交给 CDN 缓存，GPU 评分接口则受到密钥保护。
 
+### 4A. 如果要在服务器本机终结 HTTPS（可选）
+
+若总出口不做 TLS 终结，而是由服务器本机 nginx 提供 HTTPS，443 的 `server` 块必须
+包含与 80 块相同的上传相关指令，否则大文件上传会被掐断：
+
+```nginx
+server {
+    listen 443 ssl;
+    server_name videoservice.d1kt.cn;
+
+    ssl_certificate     /etc/letsencrypt/live/videoservice.d1kt.cn/fullchain.pem;
+    ssl_certificate_key /etc/letsencrypt/live/videoservice.d1kt.cn/privkey.pem;
+
+    client_max_body_size 12g;
+    client_body_timeout 7200s;
+    send_timeout 7200s;
+
+    location / {
+        proxy_pass http://127.0.0.1:8000;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_request_buffering off;
+        proxy_read_timeout 7200s;
+        proxy_send_timeout 7200s;
+    }
+
+    location ~ "^/api/v1/videos/[0-9a-fA-F]{64}/content$" {
+        proxy_pass http://127.0.0.1:8000;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header Range $http_range;
+        proxy_set_header If-Range $http_if_range;
+        proxy_force_ranges on;
+        proxy_buffering off;
+    }
+}
+```
+
+签发证书并应用：
+
+```bash
+sudo apt install -y certbot python3-certbot-nginx
+sudo certbot --nginx -d videoservice.d1kt.cn
+```
+
+### 4B. 上传中断（ClientDisconnect）排查
+
+后台日志出现 `starlette.requests.ClientDisconnect` 表示浏览器到后端之间某处的连接在
+请求体传完之前被断开。先确认实际生效的 nginx 配置：
+
+```bash
+sudo nginx -T | grep -E "client_max_body_size|client_body_timeout|proxy_request_buffering"
+```
+
+最常见的原因是新加的 HTTPS `server` 块漏掉了上传指令：nginx 默认
+`client_max_body_size` 只有 1 MB，超过会直接返回 413 并断开连接，后端表现为
+`ClientDisconnect`。其他常见原因：
+
+- 总出口（网关/CDN）有更小的请求体大小或更短的上传超时，需在网关侧放行。
+- `client_body_timeout`（默认 60s）过短：网络慢时上传暂停过久会被掐断，按上文设
+  为 7200s。
+- 浏览器/客户端主动取消或网络中断。
+
+绕过网关在本机回源验证（能通则问题在网关）：
+
+```bash
+curl -X PUT -H 'Host: videoservice.d1kt.cn' -H "X-Admin-Key: $ADMIN_KEY" \
+  --data-binary @large.mp4 \
+  'http://127.0.0.1/api/v1/admin/videos/raw?filename=large.mp4' \
+  -o /dev/null -w '%{http_code}\n'
+```
+
+API 已对 `ClientDisconnect` 做优雅处理：连接中断时返回 400 并记录一条 WARNING，
+不再产生 500 堆栈日志。
+
 ## 5. 上传与处理流程
 
 后台上传后，服务会：

sentence_api/main.py

@@ -22,6 +22,7 @@ from fastapi import (
 from fastapi.responses import FileResponse, Response
 from fastapi.staticfiles import StaticFiles
 from starlette.concurrency import run_in_threadpool
+from starlette.requests import ClientDisconnect
 
 from .assessment import AssessmentService
 from .audio_metrics import AudioAnalysisError
@@ -96,6 +97,14 @@ def create_app(
     if static_dir.is_dir():
         application.mount("/static", StaticFiles(directory=static_dir), name="static")
 
+    @application.exception_handler(ClientDisconnect)
+    async def handle_client_disconnect(request: Request, exc: ClientDisconnect) -> Response:
+        logger.warning(
+            "Upload interrupted: the client or an intermediate proxy closed the "
+            "connection before the request body completed."
+        )
+        return Response(status_code=400, content="Upload connection was interrupted.")
+
     def require_admin(x_admin_key: Optional[str] = Header(default=None)) -> None:
         expected = service_settings.admin_api_key
         if expected and not hmac.compare_digest(x_admin_key or "", expected):