Assistant

Assistant (com.kangrio.byd.assistant) is an Android utility and voice interaction bridge tailored for BYD vehicle infotainment units (DiLink) and custom Android head units / AOSP devices.

Launcher shortcuts directly to your preferred AI voice assistant (Google Assistant, ChatGPT, Perplexity, Claude, etc.), provides always-listening offline hotword / wake-word detection ("Hey Rio", "Alexa", "Snowboy", or custom trained models), and includes a modern onboarding wizard to configure system-level voice interaction services with ease.

---

Key Features

• One-Tap Voice Launcher:

  • Launching the app via home launcher icon, steering wheel button, or widget immediately invokes your selected voice assistant without opening configuration screens once set up.
  • Custom launch profiles:
    • Google App / Google Assistant: Executes android.intent.action.VOICE_COMMAND.
    • ChatGPT: Direct intent target to ChatGPT's voice assistant mode (com.openai.voice.assistant.AssistantActivity).
    • Other AI / Voice Interaction Services: Dispatches standard Intent.ACTION_ASSIST.
  • Optional audible start chime ("ding") confirmation sound upon activation.

• Offline Hotword & Wake-Word Detection (VoiceWakeService):

  • Continuous, low-latency wake-word detection powered by embedded Snowboy engine.
  • Ships with bundled offline models: Hey Rio (hey_rio.pmdl), Alexa (alexa.pmdl), and Snowboy (snowboy.pmdl).
  • Configurable microphone input gain and detection sensitivity sliders.
  • Runs efficiently as a foreground service with a persistent notification and quick-access settings.

• In-App Custom Wake-Word Trainer:

  • Built-in training studio powered by Snowboy Seasalt API.
  • Record voice samples directly on the head unit / device (minimum 3 samples).
  • Train custom .pmdl wake-word models on the fly.

• Guided Jetpack Compose Onboarding Wizard (PermissionOnboardingActivity):

  • Interactive status check and setup workflow for all required capabilities:
    1. Microphone Access: Grants audio capture for hotword detection.
    2. Display Over Other Apps: Allows launching the assistant UI seamlessly over active apps (e.g. navigation / media).
    3. Auto-Start & Battery Management: Native handling for BYD DiLink (BYD_APPSTARTMANAGEMENT) and standard Android battery optimization bypass.
    4. Write Secure Settings: Automatic on-device grant via local ADB socket (dadb) or manual ADB command copy.
    5. Target AI Assistant Selection: Scans installed VoiceInteractionService providers and allows 1-tap switching.
    6. Notification Permission: Enables background status indication (Android 13+).

• Boot Persistence:

  • BootReceiver captures BOOT_COMPLETED to re-apply Settings.Secure assistant keys and initialize the voice wake service on startup.

---

Architecture & Flow

                             +---------------------------+
                             |   User Launches App       |
                             |   or Wake Word Detected   |
                             +-------------+-------------+
                                           |
                                           v
                             +---------------------------+
                             |       StartActivity       |
                             +-------------+-------------+
                                           |
                               Is Setup Fully Completed?
                      (Secure Settings, Audio, Assistant App,
                         Auto-Start, Overlay Permissions)
                                    /             \
                                  YES              NO
                                  /                 \
                                 v                   v
             +-----------------------+   +--------------------------------+
             | Trigger Voice Command |   | PermissionOnboardingActivity   |
             |  - Google Assistant   |   |   (Setup Wizard)    |
             |  - ChatGPT Voice      |   +--------------------------------+
             |  - Custom Assist App  |
             +-----------------------+

---

Secure Settings

To designate the default voice interaction provider system-wide, the app configures the following Settings.Secure keys:

Key	Description / Example Value
assistant	Flattened component name (e.g., com.google.android.googlequicksearchbox/com.google.android.voiceinteraction.GsaVoiceInteractionService)
voice_interaction_service	Flattened component name (e.g., com.google.android.googlequicksearchbox/com.google.android.voiceinteraction.GsaVoiceInteractionService)

---

Setup & Permissions

Granting WRITE_SECURE_SETTINGS

Modifying system assistant keys requires the android.permission.WRITE_SECURE_SETTINGS permission.

Method 1: Automatic In-App Grant (Local ADB)

1. Open the app onboarding screen.
2. Under Write Secure Settings, tap Grant via Local ADB.
3. The app connects to the local ADB daemon via dadb and grants the permission automatically without needing a computer.

Method 2: Manual ADB Command

If local ADB discovery is unavailable, execute the following command via PC or Wireless ADB:

adb shell pm grant com.kangrio.byd.assistant android.permission.WRITE_SECURE_SETTINGS

---

Project Structure

Assistant/
├── app/
│   ├── build.gradle.kts
│   └── src/
│       └── main/
│           ├── AndroidManifest.xml
│           ├── assets/
│           │   └── snowboy/              # Pretrained models (.pmdl) & resources
│           │       ├── common.res
│           │       └── models/
│           │           ├── alexa.pmdl
│           │           ├── hey_rio.pmdl
│           │           └── snowboy.pmdl
│           ├── java/com/kangrio/byd/assistant/
│           │   ├── App.kt                # Application entry point
│           │   ├── Constant.kt           # Shared constants & preference keys
│           │   ├── StartActivity.kt      # Fast launcher & voice intent dispatcher
│           │   ├── activity/
│           │   │   ├── PermissionOnboardingActivity.kt # Guided onboarding host
│           │   │   └── SettingsActivity.kt             # Hotword settings & voice trainer
│           │   ├── data/
│           │   │   └── AssistantApp.kt   # Assistant metadata model
│           │   ├── receiver/
│           │   │   └── BootReceiver.kt   # Restores settings & service on boot
│           │   ├── service/
│           │   │   ├── SnowboyDetector.kt# Audio recorder & Snowboy JNI bridge
│           │   │   └── VoiceWakeService.kt # Foreground service for wake word
│           │   ├── ui/
│           │   │   ├── composable/       # Shared UI components & app icons
│           │   │   ├── onboarding/       # Onboarding wizard screens & permission cards
│           │   │   └── theme/            # Material 3 theme & typography
│           │   └── util/
│           │       ├── Preferences.kt    # SharedPreferences wrapper
│           │       ├── SnowboyTrainClient.kt # API client for custom model training
│           │       └── Utils.kt          # System helpers, dadb runner & intent utilities
│           └── res/
│               └── raw/
│                   └── ding.mp3          # Activation chime
├── build.gradle.kts
└── settings.gradle.kts

---

Building from Source

Requirements

• Android Studio
• Android SDK (API 37 compile target, minSdk 24)
• Supported ABIs: armeabi-v7a, arm64-v8a, x86_64

Build Commands

# Build Debug APK
./gradlew assembleDebug

# Build Release APK
./gradlew assembleRelease

# Build Beta Variant
./gradlew assembleBeta

Artifacts will be generated in app/build/outputs/apk/<variant>/ following the naming format: Assistant-<versionName>(<versionCode>)-<variant>-<timestamp>.apk

---

Permissions Overview

Permission	Purpose
RECORD_AUDIO	Required for wake-word listening and voice sample recording.
FOREGROUND_SERVICE / FOREGROUND_SERVICE_MICROPHONE	Keeps the hotword detector running reliably in the background.
SYSTEM_ALERT_WINDOW	Enables launching assistant interfaces over active apps.
WRITE_SECURE_SETTINGS	Configures system default assistant and voice interaction services.
RECEIVE_BOOT_COMPLETED	Automatically restarts hotword service and secures settings on device boot.
REQUEST_IGNORE_BATTERY_OPTIMIZATIONS	Prevents Android OS from killing background services in standby.
POST_NOTIFICATIONS	Displays the foreground service notification on Android 13+.
INTERNET	Used for local ADB loopback socket communication and wake-word model training.

---

Credits

This project builds upon the following open-source libraries and projects:

Project	Author / Org	Description
AndroidWakeWord	Suxsem	Android library implementing openWakeWord detection using ONNX Runtime and SpeexDSP.
dadb	mobile.dev	A Kotlin library for communicating with Android devices over ADB directly from the device itself. Used here to automatically grant WRITE_SECURE_SETTINGS without needing a PC.
wakewords-collection	fwartner	Community Collection of Wake-Words for Home Assistant

---

License

Distributed under the MIT License.