routing_bloc 0.1.0

Engine-agnostic route lifecycle state machine and glanceable route progress UI for driver-assisting navigation. Flutter package with pure Dart _core exports for routing state and route progress status.

routing_bloc

Engine-agnostic route lifecycle state machine and glanceable route progress UI for driver-assisting navigation applications.

routing_bloc manages route request, loading, active-route, and error state while keeping route guidance small enough to read quickly. It depends on routing_engine for backend routing and does not require a specific engine implementation.

Features

• RoutingBloc for the 4-state route lifecycle: idle, loading, routeActive, error.
• RouteProgressBar for glanceable route guidance UI.
• ManeuverIcons for engine-agnostic maneuver icon mapping.
• Pure Dart _core exports for RoutingStatus, RoutingState, and RouteProgressStatus.
• Reusable README/example posture for edge developers.

Install

dependencies:
  routing_bloc: ^0.1.0

Quick Start

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:latlong2/latlong.dart';
import 'package:routing_bloc/routing_bloc.dart';
import 'package:routing_engine/routing_engine.dart';

class ExampleScreen extends StatelessWidget {
  const ExampleScreen({super.key, required this.engine});

  final RoutingEngine engine;

  @override
  Widget build(BuildContext context) {
    return BlocProvider(
      create: (_) => RoutingBloc(engine: engine)
        ..add(const RoutingEngineCheckRequested())
        ..add(const RouteRequested(
          origin: LatLng(35.1709, 136.8815),
          destination: LatLng(35.0831, 137.1559),
          destinationLabel: 'Toyota City Hall',
        )),
      child: BlocBuilder<RoutingBloc, RoutingState>(
        builder: (context, state) {
          return RouteProgressBar(
            status: state.hasRoute
                ? RouteProgressStatus.active
                : RouteProgressStatus.idle,
            route: state.route,
            destinationLabel: state.destinationLabel,
          );
        },
      ),
    );
  }
}

API

API	Purpose
RoutingBloc	Route request / clear / engine-check lifecycle
RoutingState	Current lifecycle state, route result, engine availability
RoutingEvent	Route request, clear, and engine-check inputs
RouteProgressBar	Glanceable route guidance presentation layer
ManeuverIcons	Maneuver type to Material icon mapping
RouteProgressStatus	Pure Dart display status for route progress UI

Routing State Machine

State	Meaning	Trigger in
idle	No route active	startup, clear
loading	Route calculation in progress	route request
routeActive	Route calculated successfully	engine success
error	Route calculation failed	engine exception

Glanceability Rule

The route progress widget exists to be read quickly while driving. Keep the primary instruction first, distance and ETA second, and avoid turning the route header into a dense control surface.

Maneuver Icons

Representative mappings:

Maneuver type	Icon
depart	Icons.flag
arrive	Icons.sports_score
left, slight_left, sharp_left	Icons.turn_left
right, slight_right, sharp_right	Icons.turn_right
straight, continue	Icons.straight
merge	Icons.merge
ramp_right, ramp_left	Icons.ramp_right

Pure Dart Core

Use the _core barrel when you only need route lifecycle models.

import 'package:routing_bloc/routing_bloc_core.dart';

const idle = RoutingState.idle();
const status = RouteProgressStatus.active;

Example

The included example app demonstrates:

• a mock RoutingEngine
• engine availability check
• route request
• route clear
• active route UI
• error path

flutter run -d linux -t example/lib/main.dart

See Also

• routing_engine - Engine-agnostic routing backend abstraction
• navigation_safety - Navigation session and safety overlay package
• map_viewport_bloc - Viewport and layer composition state machine
• offline_tiles - Offline tile management with MBTiles fallback

All of these packages are extracted from SNGNav, a driver-assisting navigation reference product.

License

BSD-3-Clause - see LICENSE.