Android expanded notification controls do not emit events because MEDIA_BUTTON intents are not handled

Summary

On Android with react-native-audio-api@0.13.3, playback controls behave differently depending on which notification UI is used:

• Compact notification widget controls work.
• Scrubbing works.
• Expanded notification / lock-screen play, pause, next, and previous controls do not emit the expected playbackNotification* events.
• In a high-frequency update path, we also observed a java.util.ConcurrentModificationException from NotificationCompatBuilder while the notification was being updated.

I searched existing issues/PRs for MEDIA_BUTTON, PlaybackNotificationReceiver, expanded notification controls, and ConcurrentModificationException NotificationCompatBuilder, but did not find an existing report for this exact Android path.

Important MRE note

I know the issue template strongly encourages a minimal reproducible example. This report is currently based on a real app reproduction, not a public MRE yet. I am filing now because the code-level cause appears small and concrete. If needed, I can follow up with a minimal public repro project that exercises only PlaybackNotificationManager.show, enableControl, and event listeners.

Environment

• react-native-audio-api: 0.13.3
• React Native: 0.81.5
• Expo SDK: 54
• Android: reproduced on Android device/build from an Expo React Native app
• New Architecture enabled
• react-native-worklets: 0.6.1

Reproduction observed in app

1. Configure and show playback notification metadata.
2. Enable controls:
   • play
   • pause
   • nextTrack
   • previousTrack
   • skipForward
   • skipBackward
   • seekTo
3. Start playback.
4. Swipe down to show the compact notification widget.
5. Press controls from the compact widget.
6. Expand the notification or use lock-screen media controls.
7. Press play/pause/next/previous.

Expected behavior

Expanded notification and lock-screen play/pause/next/previous should emit the same events as the compact notification widget:

• playbackNotificationPlay
• playbackNotificationPause
• playbackNotificationNextTrack
• playbackNotificationPreviousTrack

Actual behavior

Compact widget controls work, but expanded notification / lock-screen play/pause/next/previous controls do not emit the expected events. Scrubbing still works.

Code-level analysis

The compact controls appear to work through MediaSessionCompat.Callback in PlaybackNotification.kt:

override fun onPlay() {
  audioAPIModule.get()?.invokeHandlerWithEventNameAndEventBody(AudioEvent.PLAYBACK_NOTIFICATION_PLAY.ordinal, mapOf())
}

override fun onPause() {
  audioAPIModule.get()?.invokeHandlerWithEventNameAndEventBody(AudioEvent.PLAYBACK_NOTIFICATION_PAUSE.ordinal, mapOf())
}

override fun onSkipToNext() {
  audioAPIModule.get()?.invokeHandlerWithEventNameAndEventBody(AudioEvent.PLAYBACK_NOTIFICATION_NEXT_TRACK.ordinal, mapOf())
}

override fun onSkipToPrevious() {
  audioAPIModule.get()?.invokeHandlerWithEventNameAndEventBody(AudioEvent.PLAYBACK_NOTIFICATION_PREVIOUS_TRACK.ordinal, mapOf())
}

But expanded notification actions are created as pending intents with action PlaybackNotification.MEDIA_BUTTON:

val intent = Intent(MEDIA_BUTTON)
intent.setPackage(context.packageName)
intent.putExtra(Intent.EXTRA_KEY_EVENT, KeyEvent(KeyEvent.ACTION_DOWN, keyCode))

MediaSessionManager.kt registers that action on PlaybackNotificationReceiver:

playbackFilter.addAction(PlaybackNotification.MEDIA_BUTTON)

However, PlaybackNotificationReceiver.kt handles only:

• ACTION_NOTIFICATION_DISMISSED
• ACTION_SKIP_FORWARD
• ACTION_SKIP_BACKWARD

It does not handle PlaybackNotification.MEDIA_BUTTON or decode Intent.EXTRA_KEY_EVENT.

That seems to explain the split behavior: compact MediaSession callbacks work, while expanded PendingIntent-backed media button actions are dropped.

Local patch that fixed the app behavior

This local patch maps MEDIA_BUTTON key events to the same AudioEvent values as the MediaSession callback path:

diff --git a/android/src/main/java/com/swmansion/audioapi/system/notification/PlaybackNotificationReceiver.kt b/android/src/main/java/com/swmansion/audioapi/system/notification/PlaybackNotificationReceiver.kt
--- a/android/src/main/java/com/swmansion/audioapi/system/notification/PlaybackNotificationReceiver.kt
+++ b/android/src/main/java/com/swmansion/audioapi/system/notification/PlaybackNotificationReceiver.kt
@@ -3,6 +3,7 @@ package com.swmansion.audioapi.system.notification
 import android.content.BroadcastReceiver
 import android.content.Context
 import android.content.Intent
+import android.view.KeyEvent
 import com.swmansion.audioapi.AudioAPIModule
 import com.swmansion.audioapi.system.AudioEvent
 
@@ -40,6 +41,43 @@ class PlaybackNotificationReceiver : BroadcastReceiver() {
         val body = HashMap<String, Any>().apply { put("value", 15) }
         audioAPIModule?.invokeHandlerWithEventNameAndEventBody(AudioEvent.PLAYBACK_NOTIFICATION_SKIP_BACKWARD.ordinal, body)
       }
+
+      PlaybackNotification.MEDIA_BUTTON -> {
+        val keyEvent = if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.TIRAMISU) {
+          intent.getParcelableExtra(Intent.EXTRA_KEY_EVENT, KeyEvent::class.java)
+        } else {
+          @Suppress("DEPRECATION")
+          intent.getParcelableExtra(Intent.EXTRA_KEY_EVENT)
+        }
+
+        if (keyEvent?.action != KeyEvent.ACTION_DOWN) return
+
+        when (keyEvent.keyCode) {
+          KeyEvent.KEYCODE_MEDIA_PLAY -> {
+            audioAPIModule?.invokeHandlerWithEventNameAndEventBody(AudioEvent.PLAYBACK_NOTIFICATION_PLAY.ordinal, mapOf())
+          }
+          KeyEvent.KEYCODE_MEDIA_PAUSE -> {
+            audioAPIModule?.invokeHandlerWithEventNameAndEventBody(AudioEvent.PLAYBACK_NOTIFICATION_PAUSE.ordinal, mapOf())
+          }
+          KeyEvent.KEYCODE_MEDIA_STOP -> {
+            audioAPIModule?.invokeHandlerWithEventNameAndEventBody(AudioEvent.PLAYBACK_NOTIFICATION_STOP.ordinal, mapOf())
+          }
+          KeyEvent.KEYCODE_MEDIA_NEXT -> {
+            audioAPIModule?.invokeHandlerWithEventNameAndEventBody(AudioEvent.PLAYBACK_NOTIFICATION_NEXT_TRACK.ordinal, mapOf())
+          }
+          KeyEvent.KEYCODE_MEDIA_PREVIOUS -> {
+            audioAPIModule?.invokeHandlerWithEventNameAndEventBody(AudioEvent.PLAYBACK_NOTIFICATION_PREVIOUS_TRACK.ordinal, mapOf())
+          }
+          KeyEvent.KEYCODE_MEDIA_FAST_FORWARD -> {
+            val body = HashMap<String, Any>().apply { put("value", 15) }
+            audioAPIModule?.invokeHandlerWithEventNameAndEventBody(AudioEvent.PLAYBACK_NOTIFICATION_SKIP_FORWARD.ordinal, body)
+          }
+          KeyEvent.KEYCODE_MEDIA_REWIND -> {
+            val body = HashMap<String, Any>().apply { put("value", 15) }
+            audioAPIModule?.invokeHandlerWithEventNameAndEventBody(AudioEvent.PLAYBACK_NOTIFICATION_SKIP_BACKWARD.ordinal, body)
+          }
+        }
+      }
     }
   }
 }

Related crash observed

Before serializing notification updates in app code, we also saw this Android crash while notification controls/metadata were being updated:

java.util.ConcurrentModificationException
  java.util.ArrayList$Itr.checkForComodification(ArrayList.java:1112)
  java.util.ArrayList$Itr.next(ArrayList.java:1065)
  androidx.core.app.NotificationCompatBuilder.<init>(NotificationCompatBuilder.java:127)
  androidx.core.app.NotificationCompat$Builder.build(NotificationCompat.java:2528)
  com.swmansion.audioapi.system.notification.PlaybackNotification.buildNotification(PlaybackNotification.kt:515)
  com.swmansion.audioapi.system.notification.PlaybackNotification.updateInternal$lambda$1$lambda$0(PlaybackNotification.kt:249)

We mitigated that separately in app code by serializing show, hide, and enableControl calls, so the main upstream issue here is the missing MEDIA_BUTTON handling path.

Cache / rebuild status

This was tested after rebuilding the native Android app. The Expo/Metro cache was also reset during upgrade testing. The local patch requires a native rebuild to take effect.

Start with android/src/main/java/com/swmansion/audioapi/system/notification/PlaybackNotificationReceiver.kt and compare its handled actions with MEDIA_BUTTON registration in MediaSessionManager.kt. Trace the Intent.EXTRA_KEY_EVENT path and verify that expanded and lock-screen controls emit the expected playback notification events after a native Android rebuild.