Picovoice Platform
Flutter Quick Start

Platforms

• Flutter (2.8.1+)
• Android (5.0+, API 21+)
• iOS (11.0+)

Requirements

• Flutter SDK
• Android SDK (21+)
• JDK (8+)
• Xcode (11+)

Picovoice Account & AccessKey

Signup or Login to Picovoice Console to get your AccessKey. Make sure to keep your AccessKey secret.

Quick Start

Setup

1. Install Flutter SDK .

2. Run flutter doctor to determine any missing requirements.

3. Add the Picovoice plugin to your app project by referencing it in pubspec.yaml:

dependencies:
  picovoice_flutter: ^<version>

4. Enable the proper permission for recording with the hardware's microphone on both iOS and Android:

<key>NSMicrophoneUsageDescription</key>
<string>[Permission explanation]</string>

<uses-permission android:name="android.permission.RECORD_AUDIO"/>
<uses-permission android:name="android.permission.INTERNET"/>

Usage

1. Add a Porcupine keyword file (.ppn) and a Rhino context file (.rhn) to the assets folder in the project directory.

2. Add it to the pubspec.yaml:

flutter:
  assets:
    - assets/${KEYWORD_FILE}
    - assets/${CONTEXT_FILE}

3. Create an instance of PicovoiceManager using the constructor PicovoiceManager.create() that detects the wake word and infers intents from spoken commands:

import 'package:picovoice/picovoice_manager.dart';
import 'package:picovoice/picovoice_error.dart';

_picovoiceManager = PicovoiceManager.create(
    "{ACCESS_KEY}",
    "assets/${KEKWORD_FILE}",
    _wakeWordCallback,
    "assets/${CONTEXT_FILE}",
    _inferenceCallback);

Alternatively, if the model files are deployed to the device with a different method, the absolute paths to the files on device can be used.

The _wakeWordCallback and _inferenceCallback parameters are functions that are invoked when Porcupine detects the wake word and Rhino makes an intent inference, respectively.

void _wakeWordCallback(){    
    // wake word detected    
}

void _infererenceCallback(RhinoInference inference){
    if(inference.isUnderstood!){
        String intent = inference.intent!
        Map<String, String> slots = inference.slots!
        // take action based on inferred intent and slot values
    }
    else{
        // handle unsupported commands
    }    
}

Start audio capture and processing:

try{
    await _picovoiceManager.start();
} on PicovoiceException catch(ex){
    // deal with Picovoice init error
}

Stop it when done with Picovoice:

await _picovoiceManager.stop();

Custom Wake Words & Contexts

1. Create custom wake words and contexts with the Picovoice Console .

2. Download the custom Porcupine keyword (.ppn) and Rhino context (.rhn) files.

3. Add them to the pubspec.yaml:

flutter:
  assets:
    - assets/${CUSTOM_KEYWORD_FILE}
    - assets/${CUSTOM_CONTEXT_FILE}

4. Create an instance of PicovoiceManager using the constructor PicovoiceManager.create().

Non-English Languages

Use the corresponding model file (.pv) to infer non-English wake words and contexts. The model files for all supported languages are available on the Porcupine GitHub repository and Rhino GitHub repository .

1. Add the model files to the assets folder in the project directory as well as keyword and context files.
2. Add it to the pubspec.yaml:

flutter:
  assets:
    - assets/${CUSTOM_KEYWORD_FILE}
    - assets/${CUSTOM_CONTEXT_FILE}
    - assets/${PORCUPINE_MODEL_FILE}
    - assets/${RHINO_MODEL_FILE}

3. Create an instance of PicovoiceManager using the constructor PicovoiceManager.create():

_picovoiceManager = PicovoiceManager.create(
    "{ACCESS_KEY}",
    "assets/{CUSTOM_KEKWORD_FILE}",
    _wakeWordCallback,
    "assets/{CUSTOM_CONTEXT_FILE}",
    _inferenceCallback,
    porcupineModelPath="assets/{PORCUPINE_MODEL_FILE}",
    rhinoModelPath="assets/{RHINO_MODEL_FILE}");

Alternatively, if the model files are deployed to the device with a different method, the absolute paths to the files on device can be used.

Demo

For the Picovoice Flutter SDK, we offer demo applications that demonstrate how to use the End-to-End Picovoice platform on real-time audio streams (i.e. microphone input).

Setup

Clone the Picovoice GitHub Repository :

git clone --recurse-submodules https://github.com/Picovoice/picovoice.git

Usage

1. Replace {YOUR_ACCESS_KEY_HERE} with a valid AccessKey in the demo/flutter/lib/main.dart file:

2. Copy assets:

cd picovoice/demo/flutter
bash copy_assets.sh

NOTE: on Windows, Git Bash or another bash shell is required, or you will have to manually copy

• The android keyword into ${DEMO_FOLDER}/assets/keyword_files/android.
• The android context into ${DEMO_FOLDER}/assets/contexts/android.
• The iOS keyword into ${DEMO_FOLDER}/assets/keyword_files/ios.
• The iOS context into ${DEMO_FOLDER}/assets/contexts/ios.

3. Build and deploy the demo to your device:

flutter run

For more information on our Picovoice demos for Flutter, head over to our GitHub repository .

Resources