Implement initialize and release, fix volume

Author: veloce

CHANGELOG.md

@@ -1,3 +1,5 @@
 ## 0.0.1
 
-* TODO: Describe initial release.
+Initial release:
+- Added `load` function to load a sound file from a path
+- Added `play` function to play a sound

README.md

@@ -1,15 +1,45 @@
 # sound_effect
 
-A new Flutter plugin project.
+A Flutter plugin for playing sound effects with a simple API and the lowest
+possible latency.
 
 ## Getting Started
 
-This project is a starting point for a Flutter
-[plug-in package](https://flutter.dev/developing-packages/),
-a specialized package that includes platform-specific implementation code for
-Android and/or iOS.
+Initialize the plugin, before using any of the other methods:
 
-For help getting started with Flutter development, view the
-[online documentation](https://flutter.dev/docs), which offers tutorials,
-samples, guidance on mobile development, and a full API reference.
+```dart
+import 'package:sound_effect/sound_effect.dart';
 
+void main() async {
+  final _soundEffect = SoundEffect();
+  await _soundEffect.initialize();
+}
+```
+
+Load a sound effect, using a unique identifier and the path to the sound file:
+
+```dart
+Future<void> loadSound(String soundId) async {
+  await _soundEffect.load(soundId, 'assets/sound_effect.mp3');
+}
+```
+
+Play the sound effect:
+
+```dart
+Future<void> playSound(String soundId) async {
+  await _soundEffect.play(soundId);
+}
+```
+
+You can also play the sound effect with a custom volume:
+
+```dart
+_soundEffect.play('effect', volume: 0.5);
+```
+
+Release the loaded sounds when they are no longer needed:
+
+```dart
+_soundEffect.release();
+```

android/src/main/kotlin/org/lichess/sound_effect/SoundEffectPlugin.kt

@@ -17,15 +17,7 @@ class SoundEffectPlugin: FlutterPlugin, MethodCallHandler {
   private lateinit var channel : MethodChannel
   private lateinit var binding: FlutterPlugin.FlutterPluginBinding
 
-  private val soundPool: SoundPool = SoundPool.Builder()
-    .setMaxStreams(1)
-    .setAudioAttributes(
-      AudioAttributes.Builder()
-      .setUsage(AudioAttributes.USAGE_GAME)
-      .setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
-      .build()
-    ).build()
-
+  private var soundPool: SoundPool? = null
   private val audioMap = HashMap<String, Int>()
 
   override fun onAttachedToEngine(flutterPluginBinding: FlutterPlugin.FlutterPluginBinding) {
@@ -36,6 +28,21 @@ class SoundEffectPlugin: FlutterPlugin, MethodCallHandler {
 
   override fun onMethodCall(call: MethodCall, result: Result) {
     when (call.method) {
+      "init" -> {
+        if (soundPool !== null) {
+          result.error("Already initialized", null, null)
+          return
+        }
+        soundPool = SoundPool.Builder()
+                .setMaxStreams(1)
+                .setAudioAttributes(
+                        AudioAttributes.Builder()
+                                .setUsage(AudioAttributes.USAGE_GAME)
+                                .setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
+                                .build()
+                ).build()
+        result.success(null)
+      }
       "load" -> {
         val audioId = call.argument<String>("soundId")
         val path = call.argument<String>("path")
@@ -52,15 +59,15 @@ class SoundEffectPlugin: FlutterPlugin, MethodCallHandler {
         try {
           val assetPath = binding.flutterAssets.getAssetFilePathBySubpath(path)
           val afd = binding.applicationContext.assets.openFd(assetPath)
-          audioMap[audioId] = soundPool.load(afd, 1)
+          audioMap[audioId] = soundPool!!.load(afd, 1)
           result.success(null)
         } catch (e: Exception) {
           result.error("Failed to load sound", e.message, null)
         }
       }
       "play" -> {
         val audioId = call.argument<String>("soundId")
-        val volume = call.argument<String>("volume")?.toFloat() ?: 1f
+        val volume = call.argument<Double>("volume")?.toFloat() ?: 1f
 
         if (audioId === null) {
           result.error("Must supply a soundId", null, null)
@@ -74,10 +81,16 @@ class SoundEffectPlugin: FlutterPlugin, MethodCallHandler {
           return
         }
 
-        soundPool.play(audio, volume, volume, 1, 0, 1f)
+        soundPool?.play(audio, volume, volume, 1, 0, 1f)
 
         result.success(null)
       }
+      "release" -> {
+        soundPool?.release()
+        soundPool = null
+        audioMap.clear()
+        result.success(null)
+      }
       else -> result.notImplemented()
     }
   }

example/lib/main.dart

@@ -28,6 +28,7 @@ class _MyAppState extends State<MyApp> {
 
   Future<void> loadSounds() async {
     try {
+      await _soundEffectPlugin.initialize();
       await _soundEffectPlugin.load('demo', 'assets/sounds/demo.mp3');
       setState(() {
         _soundLoaded = true;
@@ -39,6 +40,16 @@ class _MyAppState extends State<MyApp> {
     }
   }
 
+  Future<void> releaseSounds() async {
+    await _soundEffectPlugin.release();
+  }
+
+  @override
+  void dispose() {
+    super.dispose();
+    releaseSounds();
+  }
+
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
@@ -54,14 +65,21 @@ class _MyAppState extends State<MyApp> {
             children: <Widget>[
               if (_loadError != null)
                 Text(_loadError!)
-              else if (_soundLoaded)
+              else if (_soundLoaded) ...[
                 ElevatedButton(
                   onPressed: () {
                     _soundEffectPlugin.play('demo');
                   },
                   child: const Text('Play sound'),
-                )
-              else
+                ),
+                const SizedBox(height: 16),
+                ElevatedButton(
+                  onPressed: () {
+                    _soundEffectPlugin.play('demo', volume: 0.3);
+                  },
+                  child: const Text('Play sound (30% volume)'),
+                ),
+              ] else
                 const CircularProgressIndicator(),
             ],
           ),

ios/Classes/SoundEffectPlugin.swift

@@ -8,17 +8,6 @@ public class SoundEffectPlugin: NSObject, FlutterPlugin {
   private var registrar: FlutterPluginRegistrar? = nil
 
   public static func register(with registrar: FlutterPluginRegistrar) {
-    let session: AVAudioSession = AVAudioSession.sharedInstance()
-    do {
-        try session.setCategory(AVAudioSession.Category.ambient,
-            mode: AVAudioSession.Mode.default,
-            options: [])
-        try session.setPreferredIOBufferDuration(0.005)
-        try session.setActive(true)
-    } catch let error as NSError {
-        print("Failed to set the audio session: \(error.localizedDescription)")
-    }
-
     let channel = FlutterMethodChannel(name: "org.lichess/sound_effect", binaryMessenger: registrar.messenger())
     let instance = SoundEffectPlugin()
     registrar.addMethodCallDelegate(instance, channel: channel)
@@ -27,6 +16,18 @@ public class SoundEffectPlugin: NSObject, FlutterPlugin {
 
   public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
     switch call.method {
+    case "init":
+        let session: AVAudioSession = AVAudioSession.sharedInstance()
+        do {
+            try session.setCategory(AVAudioSession.Category.ambient,
+                mode: AVAudioSession.Mode.default,
+                options: [])
+            try session.setPreferredIOBufferDuration(0.005)
+            try session.setActive(true)
+        } catch let error as NSError {
+            print("Failed to set the audio session: \(error.localizedDescription)")
+        }
+        result(nil)
     case "load":
         let args = call.arguments as! [String: Any]
         guard let audioId = args["soundId"] as? String else {
@@ -81,6 +82,9 @@ public class SoundEffectPlugin: NSObject, FlutterPlugin {
 
         player.play()
         result(nil)
+    case "release":
+        audioMap.removeAll()
+        result(nil)
     default:
         result(FlutterMethodNotImplemented)
     }

lib/sound_effect.dart

@@ -1,11 +1,19 @@
 import 'sound_effect_platform_interface.dart';
 
 class SoundEffect {
+  Future<void> initialize() {
+    return SoundEffectPlatform.instance.initialize();
+  }
+
   Future<void> load(String soundId, String path) {
     return SoundEffectPlatform.instance.load(soundId, path);
   }
 
-  Future<void> play(String soundId, [double volume = 1.0]) {
-    return SoundEffectPlatform.instance.play(soundId);
+  Future<void> play(String soundId, {double volume = 1.0}) {
+    return SoundEffectPlatform.instance.play(soundId, volume: volume);
+  }
+
+  Future<void> release() {
+    return SoundEffectPlatform.instance.release();
   }
 }

lib/sound_effect_method_channel.dart

@@ -9,15 +9,25 @@ class MethodChannelSoundEffect extends SoundEffectPlatform {
   @visibleForTesting
   final methodChannel = const MethodChannel('org.lichess/sound_effect');
 
+  @override
+  Future<void> initialize() async {
+    await methodChannel.invokeMethod<String>('init');
+  }
+
   @override
   Future<void> load(String soundId, String path) async {
     await methodChannel.invokeMethod<String>(
         'load', <String, String>{'soundId': soundId, 'path': path});
   }
 
   @override
-  Future<void> play(String soundId, [double volume = 1.0]) async {
-    await methodChannel.invokeMethod<String>('play',
-        <String, String>{'soundId': soundId, 'volume': volume.toString()});
+  Future<void> play(String soundId, {double volume = 1.0}) async {
+    await methodChannel.invokeMethod<String>(
+        'play', <String, Object>{'soundId': soundId, 'volume': volume});
+  }
+
+  @override
+  Future<void> release() async {
+    await methodChannel.invokeMethod<String>('release');
   }
 }

lib/sound_effect_platform_interface.dart

@@ -23,11 +23,19 @@ abstract class SoundEffectPlatform extends PlatformInterface {
     _instance = instance;
   }
 
+  Future<void> initialize() {
+    throw UnimplementedError('init() has not been implemented.');
+  }
+
   Future<void> load(String soundId, String path) {
     throw UnimplementedError('load() has not been implemented.');
   }
 
-  Future<void> play(String soundId, [double volume = 1.0]) {
+  Future<void> play(String soundId, {double volume = 1.0}) {
     throw UnimplementedError('play() has not been implemented.');
   }
+
+  Future<void> release() {
+    throw UnimplementedError('release() has not been implemented.');
+  }
 }