[flutter_tts] Fix bug and support setting speech volume (#263)

* Fix bug in setLanguage

* Support setVolume

* Minor cleanups

Author: HakkyuKim

packages/flutter_tts/CHANGELOG.md

@@ -8,8 +8,15 @@
 
 ## 1.1.0
 
-* All APIs now return valid values.(0 or 1, empty list, etc.)
+* All APIs now return valid values(0 or 1, empty list, etc.).
 
 ## 1.1.1
 
-* Fix calling onCancel in a successful situation and refactor native implementations
+* Fix calling onCancel in a successful situation and refactor native implementations.
+
+## 1.2.0
+
+* Fix a bug where `setLanguage()` wasn't invoked due to typo in "setLanguage".
+* Update flutter_tts to 3.2.2 and update the example app.
+* Support `setVolume()`.
+* Minor cleanups.

packages/flutter_tts/README.md

@@ -8,8 +8,8 @@ This package is not an _endorsed_ implementation of `flutter_tts`. Therefore, yo
 
 ```yaml
 dependencies:
-  flutter_tts: ^3.0.0
-  flutter_tts_tizen: ^1.1.1
+  flutter_tts: ^3.2.2
+  flutter_tts_tizen: ^1.2.0
 ```
 
 Then you can import `flutter_tts` in your Dart code:
@@ -29,3 +29,4 @@ The features supported by Tizen are as follows. Other features are not supported
  - [x] get languages
  - [x] set language
  - [x] set speech rate
+ - [x] set speech volume (requires privilege `http://tizen.org/privilege/volume.set` in `tizen_manifest.xml`)

packages/flutter_tts/example/lib/main.dart

@@ -17,6 +17,7 @@ enum TtsState { playing, stopped, paused, continued }
 class _MyAppState extends State<MyApp> {
   late FlutterTts flutterTts;
   String? language;
+  double volume = 0.5;
   double pitch = 1.0;
   double rate = 0.5;
   String? _newVoiceText;
@@ -82,6 +83,7 @@ class _MyAppState extends State<MyApp> {
   Future<dynamic> _getLanguages() => flutterTts.getLanguages;
 
   Future _speak() async {
+    await flutterTts.setVolume(volume);
     await flutterTts.setSpeechRate(rate);
 
     if (_newVoiceText != null) {
@@ -216,10 +218,22 @@ class _MyAppState extends State<MyApp> {
 
   Widget _buildSliders() {
     return Column(
-      children: [_rate()],
+      children: [_volume(), _rate()],
     );
   }
 
+  Widget _volume() {
+    return Slider(
+        value: volume,
+        onChanged: (newVolume) {
+          setState(() => volume = newVolume);
+        },
+        min: 0.0,
+        max: 1.0,
+        divisions: 10,
+        label: "Volume: $volume");
+  }
+
   Widget _rate() {
     return Slider(
       value: rate,

packages/flutter_tts/example/pubspec.yaml

@@ -5,7 +5,7 @@ publish_to: "none"
 dependencies:
   flutter:
     sdk: flutter
-  flutter_tts: ^3.0.0
+  flutter_tts: ^3.2.2
   flutter_tts_tizen:
     path: ../
 

packages/flutter_tts/example/tizen/Runner.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Tizen.NET.Sdk/1.1.5">
+<Project Sdk="Tizen.NET.Sdk/1.1.6">
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>

packages/flutter_tts/example/tizen/tizen-manifest.xml

@@ -1,11 +1,14 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest package="org.tizen.flutter_tts_tizen_example" version="1.0.0" api-version="4.0" xmlns="http://tizen.org/ns/packages">
     <profile name="common"/>
-    <ui-application appid="org.tizen.flutter_tts_tizen_example" exec="Runner.dll" type="dotnet" multiple="false" taskmanage="true" nodisplay="false" api-version="4" launch_mode="single">
+    <ui-application appid="org.tizen.flutter_tts_tizen_example" exec="Runner.dll" type="dotnet" multiple="false" taskmanage="true" nodisplay="false" api-version="4">
         <label>flutter_tts_tizen_example</label>
         <icon>ic_launcher.png</icon>
         <metadata key="http://tizen.org/metadata/prefer_dotnet_aot" value="true"/>
         <metadata key="http://tizen.org/metadata/direct-launch" value="yes"/>
     </ui-application>
     <feature name="http://tizen.org/feature/screen.size.all"/>
+    <privileges>
+        <privilege>http://tizen.org/privilege/volume.set</privilege>
+    </privileges>
 </manifest>

packages/flutter_tts/pubspec.yaml

@@ -2,7 +2,7 @@ name: flutter_tts_tizen
 description: The tizen implementation of flutter_tts plugin.
 homepage: https://github.com/flutter-tizen/plugins
 repository: https://github.com/flutter-tizen/plugins/tree/master/packages/flutter_tts
-version: 1.1.1
+version: 1.2.0
 
 dependencies:
   flutter:

packages/flutter_tts/tizen/src/flutter_tts_tizen_plugin.cc

@@ -73,9 +73,12 @@ class FlutterTtsTizenPlugin : public flutter::Plugin {
       const flutter::MethodCall<flutter::EncodableValue> &method_call,
       std::unique_ptr<flutter::MethodResult<flutter::EncodableValue>> result) {
     // Keep in sync with the return values implemented in:
-    // https://github.com/dlutton/flutter_tts/blob/master/android/src/main/java/com/tundralabs/fluttertts/FlutterTtsPlugin.java
-    // The API specification is vague, and there is no detailed description of
-    // the return value, so I mimic the Android implementation.
+    // https://github.com/dlutton/flutter_tts/blob/master/android/src/main/java/com/tundralabs/fluttertts/FlutterTtsPlugin.java.
+    // In principle, MethodResult was designed to call MethodResult.Error() to
+    // notify the dart code of any method call failures from the host platform.
+    // However, in the case of flutter_tts, it expects a return value 0 on
+    // failure(and value 1 on success). Therefore in the scope of this plugin,
+    // we call result->Success(flutter::EncodableValue(0)) to notify errors.
 
     const auto method_name = method_call.method_name();
     const auto &arguments = *method_call.arguments();
@@ -137,7 +140,6 @@ class FlutterTtsTizenPlugin : public flutter::Plugin {
       map.insert(std::pair<flutter::EncodableValue, flutter::EncodableValue>(
           "platform", "tizen"));
       result->Success(flutter::EncodableValue(std::move(map)));
-      return;
     } else if (method_name.compare("setSpeechRate") == 0) {
       if (std::holds_alternative<double>(arguments)) {
         int speed = (int)std::get<double>(arguments);
@@ -146,7 +148,7 @@ class FlutterTtsTizenPlugin : public flutter::Plugin {
         return;
       }
       result->Success(flutter::EncodableValue(0));
-    } else if (method_name.compare("setLanguages") == 0) {
+    } else if (method_name.compare("setLanguage") == 0) {
       if (std::holds_alternative<std::string>(arguments)) {
         std::string language = std::move(std::get<std::string>(arguments));
         tts_->SetDefaultLanguage(language);
@@ -160,9 +162,17 @@ class FlutterTtsTizenPlugin : public flutter::Plugin {
         list.push_back(flutter::EncodableValue(language));
       }
       result->Success(flutter::EncodableValue(list));
+    } else if (method_name.compare("setVolume") == 0) {
+      if (std::holds_alternative<double>(arguments)) {
+        double rate = std::get<double>(arguments);
+        if (tts_->SetVolume(rate)) {
+          result->Success(flutter::EncodableValue(1));
+          return;
+        }
+      }
+      result->Success(flutter::EncodableValue(0));
     } else {
       result->Error("-1", "Not supported method");
-      return;
     }
   }
 

packages/flutter_tts/tizen/src/text_to_speech.cc

@@ -4,6 +4,8 @@
 
 #include "text_to_speech.h"
 
+#include <sound_manager.h>
+
 #include "log.h"
 
 namespace {
@@ -52,6 +54,13 @@ void TextToSpeech::Prepare() {
     default_voice_type_ = voice_type;
     free(language);
   }
+  ret = sound_manager_get_max_volume(SOUND_TYPE_VOICE, &system_max_volume_);
+  if (ret != SOUND_MANAGER_ERROR_NONE) {
+    LOG_ERROR("[SOUNDMANAGER] sound_manager_get_max_volume failed: %s",
+              get_error_message(ret));
+  }
+  system_volume_ = GetSpeechVolumeInternal();
+  tts_volume_ = system_volume_;
 
   ret = tts_prepare(tts_);
   if (ret != TTS_ERROR_NONE) {
@@ -72,6 +81,7 @@ void TextToSpeech::UnregisterTtsCallback() {
 }
 
 void TextToSpeech::OnStateChanged(tts_state_e previous, tts_state_e current) {
+  SwitchVolumeOnStateChange(previous, current);
   on_state_changed_(previous, current);
 }
 
@@ -145,11 +155,58 @@ bool TextToSpeech::Pause() {
   return true;
 }
 
-bool TextToSpeech::GetSpeedRange(int *min, int *nomal, int *max) {
-  int ret = tts_get_speed_range(tts_, min, nomal, max);
+bool TextToSpeech::SetVolume(double volume_rate) {
+  tts_volume_ = static_cast<int>(system_max_volume_ * volume_rate);
+  // Change volume instantly when tts is playing.
+  if (GetState() == TTS_STATE_PLAYING) {
+    if (!SetSpeechVolumeInternal(tts_volume_)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool TextToSpeech::GetSpeedRange(int *min, int *normal, int *max) {
+  int ret = tts_get_speed_range(tts_, min, normal, max);
   if (ret != TTS_ERROR_NONE) {
     LOG_ERROR("[TTS] tts_get_speed_range failed: %s", get_error_message(ret));
     return false;
   }
   return true;
 }
+
+void TextToSpeech::SwitchVolumeOnStateChange(tts_state_e previous,
+                                             tts_state_e current) {
+  if (previous == TTS_STATE_PLAYING) {
+    // When playback is finished, save the tts_volume that might've changed
+    // from hardware key, then restore the system volume.
+    tts_volume_ = GetSpeechVolumeInternal();
+    SetSpeechVolumeInternal(system_volume_);
+  } else if (current == TTS_STATE_PLAYING) {
+    // Before playback starts, save the system volume to restore when playback
+    // is finished, then set the tts volume.
+    system_volume_ = GetSpeechVolumeInternal();
+    SetSpeechVolumeInternal(tts_volume_);
+  }
+}
+
+int TextToSpeech::GetSpeechVolumeInternal() {
+  int volume;
+  int ret = sound_manager_get_volume(SOUND_TYPE_VOICE, &volume);
+  if (ret != SOUND_MANAGER_ERROR_NONE) {
+    LOG_ERROR("[SOUNDMANAGER] sound_manager_get_volume failed: %s",
+              get_error_message(ret));
+    volume = 0;
+  }
+  return volume;
+}
+
+bool TextToSpeech::SetSpeechVolumeInternal(int volume) {
+  int ret = sound_manager_set_volume(SOUND_TYPE_VOICE, volume);
+  if (ret != SOUND_MANAGER_ERROR_NONE) {
+    LOG_ERROR("[SOUNDMANAGER] sound_manager_set_volume failed: %s",
+              get_error_message(ret));
+    return false;
+  }
+  return true;
+}

packages/flutter_tts/tizen/src/text_to_speech.h

@@ -72,7 +72,9 @@ class TextToSpeech {
 
   bool Pause();
 
-  bool GetSpeedRange(int *min, int *nomal, int *max);
+  bool SetVolume(double volume_rate);
+
+  bool GetSpeedRange(int *min, int *normal, int *max);
 
   void SetTtsSpeed(int speed) { tts_speed_ = speed; }
 
@@ -87,12 +89,18 @@ class TextToSpeech {
   void HandleAwaitSpeakCompletion(tts_state_e previous, tts_state_e current);
   void ClearUttId() { utt_id_ = 0; }
 
+  void SwitchVolumeOnStateChange(tts_state_e previous, tts_state_e current);
+  bool SetSpeechVolumeInternal(int volume);
+  int GetSpeechVolumeInternal();
+
   tts_h tts_ = nullptr;
-  tts_state_e state_ = TTS_STATE_CREATED;
   std::string default_language_;
   int default_voice_type_ = TTS_VOICE_TYPE_AUTO;
   int tts_speed_ = TTS_SPEED_AUTO;
   int utt_id_ = 0;
+  int tts_volume_ = 0;
+  int system_volume_ = 0;
+  int system_max_volume_ = 0;
   std::vector<std::string> supported_lanaguages_;
 
   OnStateChangedCallback on_state_changed_;