playing in background

android/oral-trainer-sdk/src/main/AndroidManifest.xml

@@ -1,3 +1,5 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
     <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.WAKE_LOCK" />
+    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
 </manifest>

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

@@ -69,6 +69,7 @@ class OralTrainerController internal constructor(
         )
         player = ExoPlayer.Builder(appContext)
             .setMediaSourceFactory(mediaSourceFactory)
+            .setWakeMode(C.WAKE_MODE_NETWORK)
             .build()
             .also { exoPlayer ->
                 exoPlayer.repeatMode = Player.REPEAT_MODE_ALL

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

@@ -1,6 +1,9 @@
 <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" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE_MEDIA_PLAYBACK" />
+    <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
 
     <application
         android:allowBackup="true"
@@ -19,6 +22,11 @@
             </intent-filter>
         </activity>
 
+        <service
+            android:name=".TrainingPlaybackService"
+            android:exported="false"
+            android:foregroundServiceType="mediaPlayback" />
+
         <provider
             android:name="androidx.core.content.FileProvider"
             android:authorities="${applicationId}.fileprovider"

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

@@ -44,14 +44,19 @@ class MainActivity : Activity() {
     private var translationRequest: CancellableTranslationRequest? = null
 
     private var progressBarDragging = false
+    private var trainingPlaybackServiceActive = false
 
     private val screenActionReceiver = object : BroadcastReceiver() {
         override fun onReceive(context: Context?, intent: Intent?) {
             if (intent?.action == Intent.ACTION_SCREEN_OFF) {
+                // Training playback intentionally keeps running with the screen off.
+                // The test module still pauses because recording/assessment state is UI-dependent.
+                if (screenState.activeModule == Module.TEST) {
                     testSession.onScreenOff()
                 }
             }
         }
+    }
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -149,8 +154,9 @@ class MainActivity : Activity() {
             if (bindings.hasPlayerChrome) {
                 bindings.statusText.text = "已停止配音播放"
             }
-        } else {
+        } else if (screenState.activeModule != Module.TRAIN) {
             controller.pause()
+            stopTrainingPlaybackService()
         }
         super.onPause()
     }
@@ -178,6 +184,7 @@ class MainActivity : Activity() {
     override fun onDestroy() {
         authCoordinator.reset()
         testSession.release()
+        stopTrainingPlaybackService()
         controller.release()
         explanationOverlay.release()
         translationRequest?.cancel()
@@ -221,6 +228,7 @@ class MainActivity : Activity() {
         sdk.config.userToken = null
         screenState.clearCourse()
         controller.pause()
+        stopTrainingPlaybackService()
         screenState.activeModule = Module.COURSE
         setRootView()
     }
@@ -230,6 +238,10 @@ class MainActivity : Activity() {
             testSession.stopDubbingIfNeeded()
         }
         screenState.activeModule = module
+        if (module != Module.TRAIN) {
+            controller.pause()
+            stopTrainingPlaybackService()
+        }
         if (module == Module.COURSE || module == Module.MINE) {
             catalogController.loadUserData(module) {
                 screenFactory.refreshMyContent(sdk.userApi, authSessionStore.session?.token.orEmpty())
@@ -305,6 +317,11 @@ class MainActivity : Activity() {
 
     private fun applyPlaybackSnapshot(snapshot: PlaybackSnapshot) {
         if (!bindings.hasPlayerChrome) return
+        if (screenState.activeModule == Module.TRAIN && snapshot.isPlaying) {
+            startTrainingPlaybackService()
+        } else if (!snapshot.isPlaying) {
+            stopTrainingPlaybackService()
+        }
         if (!progressBarDragging) {
             bindings.timeText.text =
                 "${PlaybackFormat.time(snapshot.positionMs)} / ${PlaybackFormat.time(snapshot.durationMs)}"
@@ -314,6 +331,18 @@ class MainActivity : Activity() {
         bindings.statusText.text = PlaybackFormat.status(snapshot)
     }
 
+    private fun startTrainingPlaybackService() {
+        if (trainingPlaybackServiceActive) return
+        TrainingPlaybackService.start(this)
+        trainingPlaybackServiceActive = true
+    }
+
+    private fun stopTrainingPlaybackService() {
+        if (!trainingPlaybackServiceActive) return
+        TrainingPlaybackService.stop(this)
+        trainingPlaybackServiceActive = false
+    }
+
     private fun applySentence(sentence: SentenceBoundary?) {
         if (!bindings.hasPlayerChrome) return
         if (sentence == null) {

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

@@ -0,0 +1,79 @@
+package cn.learningpad.oraltrainer.sample
+
+import android.app.Notification
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.PendingIntent
+import android.app.Service
+import android.content.Context
+import android.content.Intent
+import android.content.pm.ServiceInfo
+import android.os.Build
+import android.os.IBinder
+
+/** Keeps the training player alive after the screen turns off or the app backgrounds. */
+class TrainingPlaybackService : Service() {
+
+    override fun onBind(intent: Intent?): IBinder? = null
+
+    override fun onCreate() {
+        super.onCreate()
+        val manager = getSystemService(NOTIFICATION_SERVICE) as NotificationManager
+        manager.createNotificationChannel(
+            NotificationChannel(
+                CHANNEL_ID,
+                getString(R.string.training_playback_channel_name),
+                NotificationManager.IMPORTANCE_LOW,
+            ),
+        )
+    }
+
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+        val notification = buildNotification()
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+            startForeground(
+                NOTIFICATION_ID,
+                notification,
+                ServiceInfo.FOREGROUND_SERVICE_TYPE_MEDIA_PLAYBACK,
+            )
+        } else {
+            startForeground(NOTIFICATION_ID, notification)
+        }
+        return START_NOT_STICKY
+    }
+
+    private fun buildNotification(): Notification {
+        val contentIntent = PendingIntent.getActivity(
+            this,
+            0,
+            Intent(this, MainActivity::class.java).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP),
+            PendingIntent.FLAG_IMMUTABLE,
+        )
+        return Notification.Builder(this, CHANNEL_ID)
+            .setContentTitle(getString(R.string.training_playback_notification_title))
+            .setContentText(getString(R.string.training_playback_notification_text))
+            .setSmallIcon(R.drawable.ic_notification_play)
+            .setContentIntent(contentIntent)
+            .setOngoing(true)
+            .setCategory(Notification.CATEGORY_TRANSPORT)
+            .build()
+    }
+
+    companion object {
+        private const val CHANNEL_ID = "training_playback"
+        private const val NOTIFICATION_ID = 1001
+
+        fun start(context: Context) {
+            val intent = Intent(context, TrainingPlaybackService::class.java)
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+                context.startForegroundService(intent)
+            } else {
+                context.startService(intent)
+            }
+        }
+
+        fun stop(context: Context) {
+            context.stopService(Intent(context, TrainingPlaybackService::class.java))
+        }
+    }
+}

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

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="#FFFFFFFF"
+        android:pathData="M8,5v14l11,-7z" />
+</vector>

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

@@ -1,4 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <string name="app_name">八哥口语</string>
+    <string name="training_playback_channel_name">训练播放</string>
+    <string name="training_playback_notification_title">口语训练</string>
+    <string name="training_playback_notification_text">正在后台播放</string>
 </resources>

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

@@ -1,3 +1,6 @@
 <resources>
     <string name="app_name">MynaTalk</string>
+    <string name="training_playback_channel_name">Training playback</string>
+    <string name="training_playback_notification_title">Oral training</string>
+    <string name="training_playback_notification_text">Playing in the background</string>
 </resources>