fix(android): resolve media button handling

[wyrindev]

Description

Fixes #38.

This PR addresses hardware and Bluetooth media button key event dispatching on Android and introduces audio source switching to the example application.

Changes

1. Android Media Button Handling

• MediaButtonReceiver: Added an explicit BroadcastReceiver to handle ACTION_MEDIA_BUTTON intents and route KeyEvent directly to the active FlutterMediaSessionService instance in memory, avoiding ForegroundServiceStartNotAllowedException on Android 12+.
• Unified Event Handling: Refactored handleMediaKeyEvent in FlutterMediaSessionService so key events from both MediaSession.Callback.onMediaButtonEvent and onStartCommand share consistent dispatch logic to Flutter.
• AudioAttributes: Explicitly assigned USAGE_MEDIA and CONTENT_TYPE_MUSIC to forward player attributes for better system audio routing compatibility.
• Cleaned Up Obsolete Reflection: Removed legacy setMediaButtonReceiver reflection calls on sessionCompat, aligning with standard Media3 automated session binding.

2. Example App Improvements

• Audio Source Switcher: Added an audio source toggle in SettingsPanel (Official SoundHelix vs. Cloudflare CDN) to accommodate varied network latency across regions.
• AGP 9.0+ & KGP Compatibility: Updated example/android/app/build.gradle.kts to dynamically support AGP 9.0+ built-in Kotlin while safely configuring jvmTarget = 17 for both KGP 1.x and 2.x.
• .gitignore: Aligned root .gitignore with the standard Flutter repository template.

[wyrindev]

Hi @a-tunc

Apologies for the slow response—I've been quite busy with school lately.

I believe this should now be resolved in the latest branch. If you get a chance, could you give it a try with your headset and verify if media controls are functioning properly?

Thank you so much for your patience and for reporting this!

[a-tunc]

Hi @wyrindev ,

I used this branch for testing:
android-media-button-and-audio-source

I tested it on an Android 11 device with a bluetooth headset.

Unfortunately media control buttons on the headset still do not work. What I mean is there is no response from the example app whichever button I press on the headphones.

Here is the output of logcat command and I added some comments to shed a light to what I did when.

adb logcat -c && adb logcat -v time FlutterMediaSession:D MediaSessionCompat:D MediaButtonReceiver:D *:S
--------- beginning of main
--------- beginning of system

/* I connected my headphones and started the app at this point */

09-25 12:02:07.857 D/FlutterMediaSession(15274): Successfully registered custom action 'repeat' with iconResId: 2131165285
09-25 12:02:07.857 D/FlutterMediaSession(15274): Successfully registered custom action 'shuffle' with iconResId: 2131165288

/* I started playing a tune using the example app */
/* I pressed pause button on headset. Nothing appeared here */
/* I pressed skip-to-next and skip-to-previous buttons on headset in that order. Nothing appeared here */

/* I pressed pause on the lock screen media controls. Below lines appeared */
09-25 12:02:48.571 I/FlutterMediaSession(15274): onMediaButtonEvent: action=0, keyCode=85
09-25 12:02:48.571 I/FlutterMediaSession(15274): handleMediaKeyEvent: action=0, keyCode=85
09-25 12:02:48.572 I/FlutterMediaSession(15274): sendAction: action=pause, args=null, eventSink=true

/* I uninstalled the app at this point */

09-25 12:03:19.156 W/MediaSessionCompat(18553): Couldn't find a unique registered media button receiver in the given context.

I hope this helps.

[wyrindev]

😳 Thanks for the report and logs. I'll look into this.

[wyrindev]

After investigating the audio routing dispatch mechanism (MediaSessionService / MediaSessionStack) and examining how production media apps (such as YouTube Music) maintain backwards compatibility, introduced a dedicated compatibility layer (MediaButtonRoutingCompat) for Android 11 and older.

Verified on Android 11 (API 30) and modern Android versions—media button events are routed.

[a-tunc]

Tested on Android 11 device. I tested pause/play buttons as well as skip-to-previous and skip-to-next buttons. All of them work perfectly.!

Thank you for your time/effort to get this working.