Request audio focus for Assist voice input + output (#4308)

* Request audio focus for Assist voice input + output

 - Request exclusive focus for Assist voice input (no other applications allowed to playback)
 - Request focus with ducking allowed for Assist voice output

* Remove useless @Inject

common/build.gradle.kts

@@ -62,6 +62,7 @@ dependencies {
     implementation(libs.appcompat)
     implementation(libs.androidx.lifecycle.runtime.ktx)
     implementation(libs.androidx.lifecycle.viewmodel.ktx)
+    implementation(libs.androidx.media)
 
     api(libs.androidx.room.runtime)
     api(libs.androidx.room.ktx)

common/src/main/java/io/homeassistant/companion/android/common/util/AudioRecorder.kt

@@ -2,8 +2,13 @@ package io.homeassistant.companion.android.common.util
 
 import android.annotation.SuppressLint
 import android.media.AudioFormat
+import android.media.AudioManager
+import android.media.AudioManager.OnAudioFocusChangeListener
 import android.media.AudioRecord
 import android.media.MediaRecorder.AudioSource
+import androidx.media.AudioAttributesCompat
+import androidx.media.AudioFocusRequestCompat
+import androidx.media.AudioManagerCompat
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
@@ -16,7 +21,7 @@ import kotlinx.coroutines.launch
 /**
  * Wrapper around [AudioRecord] providing pre-configured audio recording functionality.
  */
-class AudioRecorder {
+class AudioRecorder(private val audioManager: AudioManager?) {
 
     companion object {
         // Docs: 'currently the only rate that is guaranteed to work on all devices'
@@ -42,6 +47,9 @@ class AudioRecorder {
     /** Flow emitting audio recording bytes as they come in */
     val audioBytes = _audioBytes.asSharedFlow()
 
+    private var focusRequest: AudioFocusRequestCompat? = null
+    private val focusListener = OnAudioFocusChangeListener { /* Not used */ }
+
     /**
      * Start the recorder. After calling this function, data will be available via [audioBytes].
      * @throws SecurityException when missing permission to record audio
@@ -55,6 +63,7 @@ class AudioRecorder {
         if (!ready) return false
 
         if (recorderJob == null || recorderJob?.isActive == false) {
+            requestFocus()
             recorder?.startRecording()
             recorderJob = ioScope.launch {
                 val dataSize = minBufferSize()
@@ -84,6 +93,7 @@ class AudioRecorder {
         recorder?.stop()
         recorderJob?.cancel()
         recorderJob = null
+        abandonFocus()
         releaseRecorder()
     }
 
@@ -101,4 +111,34 @@ class AudioRecorder {
     }
 
     private fun minBufferSize() = AudioRecord.getMinBufferSize(SAMPLE_RATE, CHANNEL_CONFIG, AUDIO_FORMAT)
+
+    private fun requestFocus() {
+        if (audioManager == null) return
+        if (focusRequest == null) {
+            focusRequest = AudioFocusRequestCompat.Builder(AudioManagerCompat.AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE).run {
+                setAudioAttributes(
+                    AudioAttributesCompat.Builder().run {
+                        setUsage(AudioAttributesCompat.USAGE_ASSISTANT)
+                        setContentType(AudioAttributesCompat.CONTENT_TYPE_SPEECH)
+                        build()
+                    }
+                )
+                setOnAudioFocusChangeListener(focusListener)
+                build()
+            }
+        }
+
+        focusRequest?.let {
+            try {
+                AudioManagerCompat.requestAudioFocus(audioManager, it)
+            } catch (e: Exception) {
+                // We don't use the result / focus if available but if not still continue
+            }
+        }
+    }
+
+    private fun abandonFocus() {
+        if (audioManager == null || focusRequest == null) return
+        AudioManagerCompat.abandonAudioFocusRequest(audioManager, focusRequest!!)
+    }
 }

common/src/main/java/io/homeassistant/companion/android/common/util/AudioUrlPlayer.kt

@@ -1,9 +1,14 @@
 package io.homeassistant.companion.android.common.util
 
 import android.media.AudioAttributes
+import android.media.AudioManager
+import android.media.AudioManager.OnAudioFocusChangeListener
 import android.media.MediaPlayer
 import android.os.Build
 import android.util.Log
+import androidx.media.AudioAttributesCompat
+import androidx.media.AudioFocusRequestCompat
+import androidx.media.AudioManagerCompat
 import kotlin.coroutines.resume
 import kotlin.coroutines.suspendCoroutine
 import kotlinx.coroutines.Dispatchers
@@ -13,14 +18,17 @@ import kotlinx.coroutines.withContext
 /**
  * Simple interface for playing short streaming audio (from URLs).
  */
-class AudioUrlPlayer {
+class AudioUrlPlayer(private val audioManager: AudioManager?) {
 
     companion object {
         private const val TAG = "AudioUrlPlayer"
     }
 
     private var player: MediaPlayer? = null
 
+    private var focusRequest: AudioFocusRequestCompat? = null
+    private val focusListener = OnAudioFocusChangeListener { /* Not used */ }
+
     /**
      * Stream and play audio from the provided [url]. Any currently playing audio will be stopped.
      * This function will suspend until playback has started.
@@ -50,6 +58,7 @@ class AudioUrlPlayer {
                 )
                 setOnPreparedListener {
                     if (isActive) {
+                        requestFocus(isAssistant)
                         it.start()
                         cont.resume(true)
                     } else {
@@ -89,5 +98,41 @@ class AudioUrlPlayer {
     private fun releasePlayer() {
         player?.release()
         player = null
+        abandonFocus()
+    }
+
+    private fun requestFocus(isAssistant: Boolean) {
+        if (audioManager == null) return
+        if (focusRequest == null) {
+            focusRequest = AudioFocusRequestCompat.Builder(AudioManagerCompat.AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK).run {
+                setAudioAttributes(
+                    AudioAttributesCompat.Builder().run {
+                        if (isAssistant) {
+                            setUsage(AudioAttributesCompat.USAGE_ASSISTANT)
+                            setContentType(AudioAttributesCompat.CONTENT_TYPE_SPEECH)
+                        } else {
+                            setUsage(AudioAttributesCompat.USAGE_MEDIA)
+                            setContentType(AudioAttributesCompat.CONTENT_TYPE_MUSIC)
+                        }
+                        build()
+                    }
+                )
+                setOnAudioFocusChangeListener(focusListener)
+                build()
+            }
+        }
+
+        focusRequest?.let {
+            try {
+                AudioManagerCompat.requestAudioFocus(audioManager, it)
+            } catch (e: Exception) {
+                // We don't use the result / focus if available but if not still continue
+            }
+        }
+    }
+
+    private fun abandonFocus() {
+        if (audioManager == null || focusRequest == null) return
+        AudioManagerCompat.abandonAudioFocusRequest(audioManager, focusRequest!!)
     }
 }

common/src/main/java/io/homeassistant/companion/android/common/util/UtilModule.kt

@@ -1,8 +1,12 @@
 package io.homeassistant.companion.android.common.util
 
+import android.content.Context
+import android.media.AudioManager
+import androidx.core.content.getSystemService
 import dagger.Module
 import dagger.Provides
 import dagger.hilt.InstallIn
+import dagger.hilt.android.qualifiers.ApplicationContext
 import dagger.hilt.components.SingletonComponent
 import javax.inject.Singleton
 
@@ -12,9 +16,11 @@ object UtilModule {
 
     @Provides
     @Singleton
-    fun provideAudioRecorder(): AudioRecorder = AudioRecorder()
+    fun provideAudioRecorder(@ApplicationContext appContext: Context): AudioRecorder =
+        AudioRecorder(appContext.getSystemService<AudioManager>())
 
     @Provides
     @Singleton
-    fun provideAudioUrlPlayer(): AudioUrlPlayer = AudioUrlPlayer()
+    fun provideAudioUrlPlayer(@ApplicationContext appContext: Context): AudioUrlPlayer =
+        AudioUrlPlayer(appContext.getSystemService<AudioManager>())
 }

gradle/libs.versions.toml

@@ -39,6 +39,7 @@ ksp = "1.9.23-1.0.19"
 ktlint = "12.1.0"
 lifecycle = "2.7.0"
 material = "1.11.0"
+media = "1.7.0"
 media3 = "1.3.0"
 navigation-compose = "2.7.7"
 okhttp = "4.12.0"
@@ -86,6 +87,7 @@ activity-compose = { module = "androidx.activity:activity-compose", version.ref
 activity-ktx = { module = "androidx.activity:activity-ktx", version.ref = "activity-compose" }
 android-beacon-library = { module = "org.altbeacon:android-beacon-library", version.ref = "androidBeaconLibrary" }
 androidx-health-services-client = { module = "androidx.health:health-services-client", version.ref = "healthServicesClient" }
+androidx-media = { module = "androidx.media:media", version.ref = "media" }
 androidx-room-compiler = { module = "androidx.room:room-compiler", version.ref = "room" }
 androidx-room-ktx = { module = "androidx.room:room-ktx", version.ref = "room" }
 androidx-room-paging = { module = "androidx.room:room-paging", version.ref = "room" }