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Shared contract

Both the watchapp and the Android companion must agree on the UUID, the AppMessage keys, and the companion whitelist. This file is the source of truth.

UUID

c83491e7-5048-4959-aeef-fe05d7a2edd1
  • Watchapp: watchapp/package.json → pebble.uuid
  • Android: PebbleForwarder.APP_UUID

If you regenerate the UUID (uuidgen), change it in both places or the companion can't reach the watchapp.

AppMessage keys

PebbleKit Android 2 dictionaries are Map<UInt, PebbleDictionaryItem> — keys are raw integers, not names. We use explicit integer keys on both sides (no messageKeys auto-numbering). Defined once in watchapp/src/c/keys.h, mirrored in PebbleForwarder.Keys (Kotlin). Keep the two in sync.

phone → watch

# Key Type Meaning
1 NAV_ACTIVE uint8 1 = navigating, 0 = stopped (watch shows idle screen)
2 MANEUVER uint8 Maneuver enum (below) — drives the vector arrow fallback
3 ARROW_BITMAP bytes Packed 1-bpp 26×26 arrow rendered from Google's own icon
4 DISTANCE cstring Distance to next turn, e.g. "200 m"
5 STREET cstring Next road / headline instruction, e.g. "Main St"
6 INSTRUCTION cstring Full instruction text (info view)
7 ETA cstring Arrival clock time, e.g. "10:45"
8 DIST_REMAIN cstring Remaining trip distance, e.g. "4.2 mi"
9 TIME_REMAIN cstring Remaining trip time, e.g. "18 min"
10 LANES cstring Lane / extended guidance text (info view, optional)

watch → phone

# Key Type Meaning
11 REQUEST_STATE uint8 Sent on watchapp launch; phone re-pushes last NavState

The companion also re-pushes state from onAppOpened() (BasePebbleListenerService), so the watch is populated even if REQUEST_STATE is missed.

Companion whitelist (required)

PebbleKit Android 2 refuses to deliver AppMessages (FailedNoPermissions) unless the Android package is whitelisted in the watchapp's package.json under companionApp. This repo uses package com.jetboystudio.pebblenav, which must match android/app/build.gradle.kts applicationId and companionApp.android.apps[].package in watchapp/package.json.

Maneuver enum (MANEUVER)

Matches ManeuverType in watchapp/src/c/navstate.h (C) and Maneuver in NavState.kt.

Value Name Value Name
0 UNKNOWN 7 SHARP_RIGHT
1 STRAIGHT 8 UTURN
2 TURN_LEFT 9 MERGE
3 TURN_RIGHT 10 ROUNDABOUT
4 SLIGHT_LEFT 11 RAMP / EXIT
5 SLIGHT_RIGHT 12 DESTINATION
6 SHARP_LEFT

ARROW_BITMAP packing

  • 26×26 pixels, 1 bit per pixel, MSB-first within each byte.
  • Rows are byte-aligned: each row is ceil(26/8) = 4 bytes → 4 × 26 = 104 bytes total.
  • Bit = 1 means "ink" (drawn). The watch renders ink in the foreground colour, rest transparent.
  • Produced by ManeuverIcon.kt, consumed by view_common.c (ui_draw_packed_arrow).