Auto Lyrics

An Android Auto app that displays synced lyrics for the currently playing song, powered by LRCLIB.

Features

• Synced lyrics on Android Auto — shows the current lyric line with surrounding context, updated in real-time
• Works with any music player — Spotify, YouTube Music, Apple Music, Poweramp, etc.
• Phone companion view — see lyrics on your phone screen too
• Automatic song detection — picks up whatever is playing via media session APIs
• Multi-strategy lyrics lookup — tries exact match first, falls back to keyword search

Architecture

MediaListenerService (NotificationListenerService)
    │
    ▼
MediaTracker (singleton, StateFlow)
    │   ├── detects song changes → LrcLibClient → LrcParser
    │   └── tracks playback position → updates current lyric index
    │
    ├─────────────────┐
    ▼                 ▼
LyricsScreen      MainActivity
(Android Auto)    (Phone UI)

Setup

Prerequisites

• Android Studio Hedgehog (2023.1.1) or newer
• Android SDK 34
• JDK 17
• A physical Android device (Android 8.0+)

Build

1. Open the project in Android Studio
2. Sync Gradle
3. Build and install on your device:

   ./gradlew installDebug
   

First-Time Setup

1. Open Auto Lyrics on your phone
2. Grant notification access — tap the button and enable "Auto Lyrics" in the system settings
3. Play a song in any music app
4. Lyrics will appear both on the phone and on Android Auto

Testing with Android Auto Desktop Head Unit (DHU)

1. Install Android Auto Desktop Head Unit emulator from SDK Manager → SDK Tools
2. Enable Developer mode in the Android Auto app on your phone (tap version 10 times)
3. In Android Auto developer settings, enable Unknown sources
4. Start the DHU:

   cd $ANDROID_SDK/extras/google/auto/
   ./desktop-head-unit
   

5. Connect your phone via USB with the Android Auto companion app running
6. Auto Lyrics will appear in the app launcher on the DHU

Using on a real car (sideloaded APK)

Since this app is installed outside the Play Store, Android Auto requires developer mode to show it:

1. Open the Android Auto app on your phone
2. Go to Settings → scroll to the bottom → tap Version 10 times rapidly
3. You'll see a toast saying "Developer mode enabled"
4. Tap the ⋮ (three-dot) menu at the top right → Developer settings
5. Enable "Unknown sources" (allows sideloaded apps on Android Auto)
6. Restart Android Auto or disconnect/reconnect to your car
7. Auto Lyrics should now appear in the Android Auto app launcher
8. Play music — lyrics appear automatically

How It Works

1. Media detection: A NotificationListenerService grants access to MediaSessionManager, which provides the currently active media controllers
2. Song identification: When the song changes, metadata (title, artist, album, duration) is extracted from the MediaController
3. Lyrics fetch: The app queries LRCLIB — first an exact match (/api/get), then a keyword search (/api/search) as fallback
4. LRC parsing: Synced lyrics in [mm:ss.xx] text format are parsed into timestamped lines
5. Position tracking: Playback position is calculated from the media session's last reported position + elapsed time, checked every 150ms
6. Display: On Android Auto, a PaneTemplate shows 4 lyric lines centered on the current one, marked with ▶. The screen refreshes only when the active line changes.

Limitations

• Android Auto app categories: The app registers as an IOT-category Car App. For Google Play distribution, it would need to pass Android Auto app review.
• Lyrics availability: Not all songs have synced lyrics on LRCLIB. The app will show "No synced lyrics available" for missing tracks.
• Player compatibility: Most major music players expose media sessions correctly. Some niche players may not provide full metadata.
• Streaming quality tags: Some music apps (YouTube Music, Tidal, etc.) inject quality info like "Lossless" or "Hi-Res" into metadata fields. The app strips these automatically, but unusual formats may slip through.
• Sideloaded apps on Android Auto: Developer mode must be enabled in Android Auto settings to see sideloaded apps. See setup instructions above.

License

MIT