Add getVolume and setVolume for Android and iOS

android/src/main/java/bz/rxla/audioplayer/AudioplayerPlugin.java

@@ -67,6 +67,15 @@ public void onMethodCall(MethodCall call, MethodChannel.Result response) {
         mute(muted);
         response.success(null);
         break;
+      case "getVolume":
+        int volume = getVolume();
+        response.success(volume);
+        break;
+      case "setVolume":
+        int volumeToSet = call.arguments();
+        setVolume(volumeToSet);
+        response.success(null);
+        break;
       default:
         response.notImplemented();
     }
@@ -80,6 +89,28 @@ private void mute(Boolean muted) {
     }
   }
 
+  private int getVolume() {
+/*
+    //TODO: Replace volume getter with this logic to normalize to 0 to 100
+    int maxVolume = getStreamMaxVolume(AudioManager.STREAM_MUSIC);
+    int minVolume = getStreamMinVolume(AudioManager.STREAM_MUSIC);
+    int volume = (am.getStreamVolume(AudioManager.STREAM_MUSIC) - minVolume) * 100 / (maxVolume - minVolume);
+*/
+    int volume = am.getStreamVolume(AudioManager.STREAM_MUSIC);
+    return volume;
+  }
+
+  private void setVolume(int volume) {
+/*
+    //TODO: Replace volume setter with this logic to normalize to 0 to 100
+    int maxVolume = getStreamMaxVolume(AudioManager.STREAM_MUSIC);
+    int minVolume = getStreamMinVolume(AudioManager.STREAM_MUSIC);
+    int index = volume * (maxVolume - minVolume) / 100 + minVolume;
+*/
+    int index = volume;
+    am.setStreamVolume(AudioManager.STREAM_MUSIC, index, 0);
+  }
+
   private void seek(double position) {
     mediaPlayer.seekTo((int) (position * 1000));
   }

example/lib/main.dart

@@ -26,6 +26,7 @@ class AudioApp extends StatefulWidget {
 class _AudioAppState extends State<AudioApp> {
   Duration duration;
   Duration position;
+  int _volume;
 
   AudioPlayer audioPlayer;
 
@@ -62,6 +63,7 @@ class _AudioAppState extends State<AudioApp> {
 
   void initAudioPlayer() {
     audioPlayer = new AudioPlayer();
+    audioPlayer.setVolume(10);
     _positionSubscription = audioPlayer.onAudioPositionChanged.listen(
       (p) => setState(() => position = p)
     );
@@ -88,6 +90,11 @@ class _AudioAppState extends State<AudioApp> {
     setState(() {
       playerState = PlayerState.playing;
     });
+    audioPlayer.getVolume().then((volume) {
+      setState(() {
+        _volume = volume;
+      });
+    });
   }
 
   Future _playLocal() async {
@@ -206,19 +213,6 @@ class _AudioAppState extends State<AudioApp> {
                     audioPlayer.seek((value / 1000).roundToDouble()),
                 min: 0.0,
                 max: duration.inMilliseconds.toDouble()),
-        new Row(
-          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
-          children: <Widget>[
-            new IconButton(
-                onPressed: () => mute(true),
-                icon: new Icon(Icons.headset_off),
-                color: Colors.cyan),
-            new IconButton(
-                onPressed: () => mute(false),
-                icon: new Icon(Icons.headset),
-                color: Colors.cyan),
-          ],
-        ),
         new Row(mainAxisSize: MainAxisSize.min, children: [
           new Padding(
               padding: new EdgeInsets.all(12.0),
@@ -229,7 +223,7 @@ class _AudioAppState extends State<AudioApp> {
                 new CircularProgressIndicator(
                   value: position != null && position.inMilliseconds > 0
                       ? (position?.inMilliseconds?.toDouble() ?? 0.0) /
-                          (duration?.inMilliseconds?.toDouble() ?? 0.0)
+                      (duration?.inMilliseconds?.toDouble() ?? 0.0)
                       : 0.0,
                   valueColor: new AlwaysStoppedAnimation(Colors.cyan),
                   backgroundColor: Colors.yellow,
@@ -240,6 +234,38 @@ class _AudioAppState extends State<AudioApp> {
                   ? "${positionText ?? ''} / ${durationText ?? ''}"
                   : duration != null ? durationText : '',
               style: new TextStyle(fontSize: 24.0))
-        ])
+        ]),
+        new Row(
+          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+          children: <Widget>[
+            new IconButton(
+                onPressed: () => mute(true),
+                icon: new Icon(Icons.headset_off),
+                color: Colors.cyan),
+            new IconButton(
+                onPressed: () => mute(false),
+                icon: new Icon(Icons.headset),
+                color: Colors.cyan),
+          ],
+        ),
+        new Row (
+          children: <Widget>[
+            new Icon(Icons.volume_down),
+            new Expanded(child:
+              new Slider(
+                min: 0.0,
+                max: 100.0,
+                value: _volume?.toDouble() ?? 50.0,
+                onChanged: (double newValue) {
+                  setState(() {
+                    _volume = newValue.toInt();
+                  });
+                  audioPlayer.setVolume(_volume);
+                },
+              ),
+            ),
+            new Icon(Icons.volume_up),
+          ],
+        ),
       ]));
 }

ios/Classes/AudioplayerPlugin.m

@@ -12,6 +12,8 @@ @interface AudioplayerPlugin()
 -(void)pause;
 -(void)stop;
 -(void)mute:(BOOL)muted;
+-(NSNumber *)getVolume;
+-(void)setVolume:(int)volume;
 -(void)seek:(CMTime)time;
 -(void)onStart;
 -(void)onTimeInterval:(CMTime)time;
@@ -61,6 +63,16 @@ - (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
                                 [self mute:[call.arguments boolValue]];
                                 result(nil);
                               },
+                            @"getVolume":
+                              ^{
+                                NSNumber *volumeRef = [self getVolume];
+                                result(volumeRef);
+                              },
+                            @"setVolume":
+                              ^{
+                                [self setVolume:[call.arguments intValue]];
+                                result(nil);
+                              },
                             @"seek":
                               ^{
                                 [self seek:CMTimeMakeWithSeconds([call.arguments doubleValue], 1)];
@@ -159,6 +171,16 @@ - (void)mute:(bool)muted {
   player.muted = muted;
 }
 
+- (NSNumber *)getVolume {
+    int volume = (int)roundf(player.volume * 100.0);
+    NSNumber *volumeRef = [NSNumber numberWithInt:volume];
+    return volumeRef;
+}
+
+- (void)setVolume:(int)volume {
+  player.volume = (float)volume / 100.0;
+}
+
 - (void)seek:(CMTime)time {
   [playerItem seekToTime:time];
 }

lib/audioplayer.dart

@@ -55,6 +55,12 @@ class AudioPlayer {
   /// Mute sound.
   Future<void> mute(bool muted) async => await _channel.invokeMethod('mute', muted);
 
+  /// Get playing volume. Normalized integer range of 0 to 100.
+  Future<int> getVolume() async => await _channel.invokeMethod('getVolume');
+
+  /// Set playing volume. Normalized integer range of 0 to 100.
+  Future<void> setVolume(int volume) async => await _channel.invokeMethod('setVolume', volume);
+
   /// Seek to a specific position in the audio stream.
   Future<void> seek(double seconds) async => await _channel.invokeMethod('seek', seconds);