feat(android): add setBalance (#58) (#1444)

Author: Gustl22

feature_parity_table.md

@@ -59,7 +59,7 @@ Note: LLM means Low Latency Mode.
         <tr><td>stay awake</td><td>yes (except LLM)</td><td>yes</td><td>no</td><td>no</td><td>no</td><td>no</td></tr>
         <tr><td>recording active</td><td>not yet</td><td>yes</td><td>no</td><td>no</td><td>no</td><td>no</td></tr>
         <tr><td>playing route</td><td>yes (except LLM)</td><td>yes</td><td>no</td><td>no</td><td>no</td><td>no</td></tr>
-        <tr><td>balance</td><td>not yet</td><td>not yet</td><td>not yet</td><td>yes</td><td>yes</td><td>yes</td></tr>
+        <tr><td>balance</td><td>yes</td><td>not yet</td><td>not yet</td><td>yes</td><td>yes</td><td>yes</td></tr>
         <tr><td colspan="7"><strong>Streams</strong></td></tr>
         <tr><td>duration event</td><td>yes</td><td>yes</td><td>yes</td><td>yes</td><td>yes</td><td>yes</td></tr>
         <tr><td>position event</td><td>yes</td><td>yes</td><td>yes</td><td>yes</td><td>yes</td><td>yes</td></tr>

packages/audioplayers/example/integration_test/platform_features.dart

@@ -20,7 +20,6 @@ class PlatformFeatures {
 
   static const androidPlatformFeatures = PlatformFeatures(
     hasRecordingActive: false,
-    hasBalance: false,
   );
 
   static const iosPlatformFeatures = PlatformFeatures(

packages/audioplayers_android/android/src/main/kotlin/xyz/luan/audioplayers/AudioplayersPlugin.kt

@@ -124,9 +124,8 @@ class AudioplayersPlugin : FlutterPlugin, IUpdateCallback {
             }
 
             "setBalance" -> {
-                Logger.error("setBalance is not currently implemented on Android")
-                response.notImplemented()
-                return
+                val balance = call.argument<Double>("balance") ?: error("balance is required")
+                player.balance = balance.toFloat()
             }
 
             "setPlaybackRate" -> {

packages/audioplayers_android/android/src/main/kotlin/xyz/luan/audioplayers/player/MediaPlayerPlayer.kt

@@ -36,8 +36,8 @@ class MediaPlayerPlayer(
         return mediaPlayer.isPlaying
     }
 
-    override fun setVolume(volume: Float) {
-        mediaPlayer.setVolume(volume, volume)
+    override fun setVolume(leftVolume: Float, rightVolume: Float) {
+        mediaPlayer.setVolume(leftVolume, rightVolume)
     }
 
     override fun setRate(rate: Float) {

packages/audioplayers_android/android/src/main/kotlin/xyz/luan/audioplayers/player/Player.kt

@@ -15,7 +15,7 @@ interface Player {
     fun seekTo(position: Int)
     fun release()
 
-    fun setVolume(volume: Float)
+    fun setVolume(leftVolume: Float, rightVolume: Float)
     fun setRate(rate: Float)
     fun setLooping(looping: Boolean)
     fun updateContext(context: AudioContextAndroid)

packages/audioplayers_android/android/src/main/kotlin/xyz/luan/audioplayers/player/SoundPoolPlayer.kt

@@ -124,8 +124,8 @@ class SoundPoolPlayer(
         }
     }
 
-    override fun setVolume(volume: Float) {
-        streamId?.let { soundPool.setVolume(it, volume, volume) }
+    override fun setVolume(leftVolume: Float, rightVolume: Float) {
+        streamId?.let { soundPool.setVolume(it, leftVolume, rightVolume) }
     }
 
     override fun setRate(rate: Float) {

packages/audioplayers_android/android/src/main/kotlin/xyz/luan/audioplayers/player/WrappedPlayer.kt

@@ -3,6 +3,7 @@ package xyz.luan.audioplayers.player
 import android.content.Context
 import android.media.AudioManager
 import android.media.MediaPlayer
+import kotlin.math.min
 import xyz.luan.audioplayers.AudioContextAndroid
 import xyz.luan.audioplayers.AudioplayersPlugin
 import xyz.luan.audioplayers.PlayerMode
@@ -44,7 +45,17 @@ class WrappedPlayer internal constructor(
             if (field != value) {
                 field = value
                 if (!released) {
-                    player?.setVolume(value)
+                    player?.setVolumeAndBalance(value, balance)
+                }
+            }
+        }
+
+    var balance = 0.0f
+        set(value) {
+            if (field != value) {
+                field = value
+                if (!released) {
+                    player?.setVolumeAndBalance(volume, value)
                 }
             }
         }
@@ -324,8 +335,14 @@ class WrappedPlayer internal constructor(
 
     private fun Player.configAndPrepare() {
         setRate(rate)
-        setVolume(volume)
+        setVolumeAndBalance(volume, balance)
         setLooping(isLooping)
         prepare()
     }
+
+    private fun Player.setVolumeAndBalance(volume: Float, balance: Float) {
+        val leftVolume = min(1f, 1f - balance) * volume
+        val rightVolume = min(1f, 1f + balance) * volume
+        setVolume(leftVolume, rightVolume)
+    }
 }