Post notification for session app when FgS starting exception is caught

PiperOrigin-RevId: 502407886
(cherry picked from commit 6ce3421c)

demos/session/src/main/java/androidx/media3/demo/session/PlaybackService.kt

@@ -15,22 +15,22 @@
  */
 package androidx.media3.demo.session
 
-import android.app.PendingIntent.FLAG_IMMUTABLE
-import android.app.PendingIntent.FLAG_UPDATE_CURRENT
+import android.app.Notification.BigTextStyle
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.PendingIntent.*
 import android.app.TaskStackBuilder
 import android.content.Intent
 import android.os.Build
 import android.os.Bundle
+import androidx.core.app.NotificationCompat
+import androidx.core.app.NotificationManagerCompat
 import androidx.media3.common.AudioAttributes
 import androidx.media3.common.MediaItem
+import androidx.media3.common.util.Util
 import androidx.media3.exoplayer.ExoPlayer
-import androidx.media3.session.CommandButton
-import androidx.media3.session.LibraryResult
-import androidx.media3.session.MediaLibraryService
-import androidx.media3.session.MediaSession
+import androidx.media3.session.*
 import androidx.media3.session.MediaSession.ControllerInfo
-import androidx.media3.session.SessionCommand
-import androidx.media3.session.SessionResult
 import com.google.common.collect.ImmutableList
 import com.google.common.util.concurrent.Futures
 import com.google.common.util.concurrent.ListenableFuture
@@ -51,6 +51,8 @@ class PlaybackService : MediaLibraryService() {
       "android.media3.session.demo.SHUFFLE_ON"
     private const val CUSTOM_COMMAND_TOGGLE_SHUFFLE_MODE_OFF =
       "android.media3.session.demo.SHUFFLE_OFF"
+    private const val NOTIFICATION_ID = 123
+    private const val CHANNEL_ID = "demo_session_notification_channel_id"
   }
 
   override fun onCreate() {
@@ -66,6 +68,7 @@ class PlaybackService : MediaLibraryService() {
       )
     customLayout = ImmutableList.of(customCommands[0])
     initializeSessionAndPlayer()
+    setListener(MediaSessionServiceListener())
   }
 
   override fun onGetSession(controllerInfo: ControllerInfo): MediaLibrarySession {
@@ -81,6 +84,7 @@ class PlaybackService : MediaLibraryService() {
   override fun onDestroy() {
     player.release()
     mediaLibrarySession.release()
+    clearListener()
     super.onDestroy()
   }
 
@@ -259,4 +263,54 @@ class PlaybackService : MediaLibraryService() {
   private fun ignoreFuture(customLayout: ListenableFuture<SessionResult>) {
     /* Do nothing. */
   }
+
+  private inner class MediaSessionServiceListener : Listener {
+
+    /**
+     * This method is only required to be implemented on Android 12 or above when an attempt is made
+     * by a media controller to resume playback when the {@link MediaSessionService} is in the
+     * background.
+     */
+    override fun onForegroundServiceStartNotAllowedException() {
+      createNotificationAndNotify()
+    }
+  }
+
+  private fun createNotificationAndNotify() {
+    var notificationManagerCompat = NotificationManagerCompat.from(this)
+    ensureNotificationChannel(notificationManagerCompat)
+    var pendingIntent =
+      TaskStackBuilder.create(this).run {
+        addNextIntent(Intent(this@PlaybackService, MainActivity::class.java))
+
+        val immutableFlag = if (Build.VERSION.SDK_INT >= 23) FLAG_IMMUTABLE else 0
+        getPendingIntent(0, immutableFlag or FLAG_UPDATE_CURRENT)
+      }
+
+    var builder =
+      NotificationCompat.Builder(this, CHANNEL_ID)
+        .setContentIntent(pendingIntent)
+        .setSmallIcon(R.drawable.media3_notification_small_icon)
+        .setContentTitle(getString(R.string.notification_content_title))
+        .setStyle(
+          NotificationCompat.BigTextStyle().bigText(getString(R.string.notification_content_text))
+        )
+        .setPriority(NotificationCompat.PRIORITY_DEFAULT)
+        .setAutoCancel(true)
+    notificationManagerCompat.notify(NOTIFICATION_ID, builder.build())
+  }
+
+  private fun ensureNotificationChannel(notificationManagerCompat: NotificationManagerCompat) {
+    if (Util.SDK_INT < 26 || notificationManagerCompat.getNotificationChannel(CHANNEL_ID) != null) {
+      return
+    }
+
+    val channel =
+      NotificationChannel(
+        CHANNEL_ID,
+        getString(R.string.notification_channel_name),
+        NotificationManager.IMPORTANCE_DEFAULT
+      )
+    notificationManagerCompat.createNotificationChannel(channel)
+  }
 }

demos/session/src/main/res/values/strings.xml

@@ -24,4 +24,9 @@
   <string name="no_item_prompt">
     "! No media in the play list !\nPlease try to add more from browser"
   </string>
+  <string name="notification_content_title">Playback cannot be resumed</string>
+  <string name="notification_content_text">Press on the play button on the media notification if it
+    is still present, otherwise please open the app to start the playback and re-connect the session
+    to the controller</string>
+  <string name="notification_channel_name">Playback cannot be resumed</string>
 </resources>