CarLauncher

A personal Android car launcher for a tablet mounted on the dashboard. It replaces the default Android home screen with a fullscreen, landscape-only interface built for driving: a 3D Mapbox map with built-in turn-by-turn navigation, music, weather, a trip log and a manual dashcam.

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What it looks like

The launcher has three pages you swipe between (dot indicator above the dock):

Page	Content
0 — Launcher	Map / navigation panel + music, volume & brightness, weather & calendar
1 — Widgets	Android AppWidget grid with swipeable widget stacks
2 — Trips	Trip computer + driving log

+--------------------------------------+-------------------+
|                                      |   MusicWidget     |
|        MapNavPanel (~65 %)           |                   |
|   Mapbox 3D map  <-long press->      +-------------------+
|   navigation from Google Maps/Mapy   | Volume | Brightness|
|                                      +-------------------+
|                                      | Weather | Calendar |
+--------------------------------------+-------------------+
| (Menu)      ( app slots . split-screen slots )  time/batt |
+----------------------------------------------------------+

There is no status bar on purpose — the map gets the space. Time, battery and weather live in the bottom-right corner of the dock.

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Screenshots

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Features

Map (Mapbox Maps SDK)

• Mapbox Standard style — 3D buildings and landmarks, night light preset, 45° pitch
• Live traffic layer coloured by congestion
• Parking pins from OpenStreetMap (Overpass API)
• Vehicle puck fed by the app's own Kalman-filtered GPS
• Auto-follow camera; a locate-me button recentres instantly and shows whether the camera is following
• Tap a POI or parking pin → card with name, distance and a Navigate button
• Online only — no offline fallback

Built-in navigation (Mapbox Navigation + Search SDK)

• Destination search — full-panel search with live suggestions, recent searches and voice input
• POI categories — fuel, parking, restaurants, shops, coffee — with numbered pins on the map
• Picking a destination starts guidance immediately (no preview step)
• Maneuver banner, trip progress (ETA / distance / time), route line and a follow camera
• Voice guidance in the device language
• Navigation ends automatically on arrival; it keeps running when you switch the panel

Navigation from other apps

• Reads Google Maps and Mapy.cz turn-by-turn notifications via NotificationListenerService
• Shows distance to the next maneuver, street, maneuver icon, ETA and an end button
• Long press on the left panel (1.5 s) switches between Map and this Navigation view; active navigation always wins
• Waze, TomTom and HERE WeGo only post placeholder notifications, so they aren't supported

Trip computer & driving log

• Trips are detected automatically (moving > 5 km/h for 10 s starts a trip, 30 s stationary ends it)
• Stored in a Room database; live trip stats plus a history list
• CSV export via the Android share sheet

Incident recorder (manual dashcam)

• Draggable floating button opens a fullscreen camera overlay
• Records video with CameraX (HD, no audio) to the app's external files folder
• Logs GPS and detects licence plates (ML Kit text recognition, offline) during recording
• Writes a JSON sidecar next to each .mp4 with timestamps, GPS track and detected plates — the video itself is untouched
• Can be switched off with the INCIDENT_RECORDER_ENABLED build flag

Music

• Reads the active MediaSession — album art, title, artist, progress, play / pause / skip
• Needs notification access; shows a grant button if it's missing

Volume & brightness

• Two cards with a coloured fill that rises with the level
• Swipe up / down to change (1.5× sensitivity); brightness uses the window attribute, no WRITE_SETTINGS

Weather & calendar

• Weather: Open-Meteo (free, no key), refreshed every 30 min, Prague fallback without GPS
• Calendar: today's events from CalendarContract (max 3)

Dock

• Floating circular dock: Menu (app drawer) pinned left, app slots in the middle, time / battery / weather pinned right
• Slots can hold a single app or a split-screen pair (navigation left, music right); split-screen slots are locked
• Long press a slot to reassign it; configuration is stored in DataStore

Widgets page

• Hosts regular Android home-screen widgets in three layout templates
• Each slot is a vertical stack you swipe through; long press for edit mode

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Tech stack

Layer	Technology
Language / UI	Kotlin, Jetpack Compose
DI	Hilt
Map	Mapbox Maps SDK (Standard style)
Navigation & search	Mapbox Navigation SDK, Mapbox Search Box SDK
Location	FusedLocationProviderClient + 2D Kalman filter
Persistence	DataStore Preferences, Room (trips)
Camera / ML	CameraX, ML Kit Text Recognition v2 (bundled)
Media & 3rd-party nav	MediaSessionManager + NotificationListenerService
Weather	Open-Meteo REST API
Parking / speed limit	OpenStreetMap Overpass, Nominatim
Calendar	Android CalendarContract

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Target device

Property	Value
Device	Lenovo Tab M10 Plus (3rd Gen)
Chipset	MediaTek Helio G80
Android	16 (API 36)
Screen	~1143 × 686 dp, landscape locked, fullscreen
minSdk	31
compileSdk / targetSdk	36

Emulator note: use an API 34 (Android 14) x86_64 image with Google Play. API 35+ emulators enforce 16 KB page alignment for native libraries, which hasn't been verified for the Mapbox .so files. The Helio G80 device is not affected.

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Build & install

Prerequisites

• Android Studio (recent stable)
• Two Mapbox tokens from https://account.mapbox.com/access-tokens/

Mapbox tokens

# local.properties — public token (pk.…)
MAPBOX_ACCESS_TOKEN=pk.your_token

# ~/.gradle/gradle.properties — secret token (sk.…) with DOWNLOADS:READ scope,
# used only by Gradle to download the Mapbox SDK
MAPBOX_DOWNLOADS_TOKEN=sk.your_token

Gradle

./gradlew assembleDebug        # build APK
./gradlew installDebug         # build + install to connected device
./gradlew lint
./gradlew test

Manual ADB install (PowerShell)

$adb = "$env:LOCALAPPDATA\Android\Sdk\platform-tools\adb.exe"
& $adb install -r app/build/outputs/apk/debug/app-debug.apk

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First-run setup

1. Set as home app — Settings › Apps › Default apps › Home app › CarLauncher
2. Notification access (music + navigation from other apps) — Settings › Apps › Special app access › Notification access › CarLauncher
3. Location — grant Precise location when asked
4. Calendar — grant READ_CALENDAR for the calendar widget
5. Camera — asked the first time you open the incident recorder

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Architecture

Single-module app (app/), package com.example.carlauncher:

ui/
  launcher/    LauncherScreen, MapNavPanel, WeatherCalendarWidget,
               SystemControlsWidget, AppDrawer
  map/         MapWidget, MapViewModel, SearchOverlay, DestinationSearchBar
  navigation/  NavAreaWidget, NavWidget (notification-based navigation)
  music/       MusicWidget
  dock/        DockBar, SlotPicker
  widgets/     WidgetScreen, TripScreen, LongPressWidgetHost
  incident/    IncidentFab, IncidentRecorderScreen, IncidentOverlay
  theme/       CarColors (dark only)
data/
  location/    LocationRepository, LocationProcessor, KalmanFilter
  navigation/  NavRepository, MapboxVoiceGuidanceObserver,
               MapboxArrivalTeardownObserver
  trip/        TripDetector, TripRepository, Room DB, CsvExporter
  incident/    IncidentRecorder, IncidentLocationSource, PlateDetector
  poi/         ParkingRepository
  speedlimit/  weather/  calendar/  media/  dock/  widgets/  model/
di/            Hilt modules
service/       MediaListenerService (media + navigation notifications)

More detail for contributors is in CLAUDE.md.

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Planned

Feature	Status
Adaptive GPS interval (500 ms driving → 5 s parked)	planned
LocationForegroundService	manifest stub only
Licence-plate detection on ONNX (YOLO + OCR)	on a feature branch, not merged

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License

Personal project — not licensed for redistribution.