google_maps_polyline 2.2.0

Google Directions API ile iki nokta arasında rota alır, Google kodlanmış polyline dizelerini çözer ve kodlar. Saf Dart; Flutter ve sunucu tarafında çalışır.

google_maps_polyline

Fetches the route between two coordinates from the Google Directions API and decodes/encodes Google encoded polylines. Pure Dart: works in Flutter apps (Android, iOS, desktop) and on the server. Polyline decoding/encoding also works on the web; for route requests see Flutter web and CORS.

Türkçe açıklama aşağıda.

Installation

dependencies:
  google_maps_polyline: ^2.2.0

Fetching a route

import 'package:google_maps_polyline/google_maps_polyline.dart';

final polyline = GoogleMapsPolyline();

final result = await polyline.getRouteBetweenCoordinates(
  apiKey,
  const MyPointLatLng(41.0082, 28.9784), // Istanbul
  const MyPointLatLng(39.9334, 32.8597), // Ankara
  travelMode: MyTravelMode.driving,
  wayPoints: [
    WayPointPolyline(location: 'Bolu, Türkiye'),
    WayPointPolyline(location: '40.7,31.6', stopOver: false), // via:
  ],
  avoidTolls: true,
  detailedPolyline: true, // step-by-step route
);

if (result.isSuccess) {
  // With google_maps_flutter:
  final points = [for (final p in result.points) LatLng(p.latitude, p.longitude)];
} else {
  print('${result.status}: ${result.errorMessage}');
}

getRouteBetweenCoordinates never throws. result.status is the value returned by the Directions API (OK, ZERO_RESULTS, NOT_FOUND, OVER_QUERY_LIMIT, REQUEST_DENIED, INVALID_REQUEST, …), or ResultPolyline.statusError ("error") for network failures, timeouts and unreadable responses. Base your app logic on status, which does not depend on the language; errorMessage is meant for display. The API key is redacted from error messages. If the origin or destination is NaN/infinite, an error is returned without sending a request.

By default Google's simplified overview_polyline is used, which can drift from the road at high zoom. With detailedPolyline: true the route is built by joining every step polyline (more points, follows the road closely). If the response has no steps, it falls back to overview_polyline.

Optional settings:

GoogleMapsPolyline(
  client: myHttpClient,                 // your own http.Client (tests, proxy, …)
  timeout: const Duration(seconds: 10), // default 15 s
  language: 'tr',                       // default 'en'
);

Language

language is sent to the Directions API, so the API's own error_message comes back in that language. It also selects the language of the messages produced by the package (timeouts, network errors, status descriptions): tr gives Turkish, any other code English. The default is en.

Decoding and encoding polylines

final points = PolylineCodec.decode(r'_p~iF~ps|U_ulLnnqC_mqNvxq`@');
// [(38.5, -120.2), (40.7, -120.95), (43.252, -126.453)]

final encoded = PolylineCodec.encode(points); // '_p~iF~ps|U_ulLnnqC_mqNvxq`@'

// Strings with 6-digit precision (e.g. OSRM polyline6):
PolylineCodec.decode(encoded6, precision: 6);

Invalid or truncated strings throw FormatException.

Flutter web and CORS

Google's Directions web service does not allow CORS requests from browsers, so on Flutter web getRouteBetweenCoordinates always returns a network error (status == "error"). On the web, fetch the route on your own server (for example a Dart server or Cloud Function using this package), send the encoded polyline to the app and decode it in the browser with PolylineCodec.decode. The Maps JavaScript API's DirectionsService is another option for drawing routes on the web.

API key security

The Directions API is a web service; a key embedded in an app can be read by anyone who has the app. Restrict the key to the Directions API only in the Google Cloud Console and set a quota. If possible, call the API from your own server; the package is pure Dart, so it runs there too.

Directions API and Routes API

Google has marked the Directions API as Legacy and recommends the Routes API for new projects. The Directions API may not be available in Google Cloud projects created after 1 March 2025. This package uses the Directions API; the Routes API's polyline.encodedPolyline uses the same format and can be decoded with PolylineCodec.decode.

Migrating to 2.x

• MyPointLatLng.latitude/longitude are now double instead of double? (no ! needed).
• Check success with result.isSuccess instead of result.status == "ok" (the API returns "OK", so the old comparison was never true).
• All classes are exported from package:google_maps_polyline/google_maps_polyline.dart; remove src/... imports.
• The package no longer depends on Flutter.
• Since 2.2.0 the package's messages are in English by default; pass language: 'tr' to keep Turkish messages.

See example/ for a complete Flutter app (English and Turkish).

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Türkçe

Google Directions API ile iki nokta arasındaki rotayı alır ve Google kodlanmış polyline dizelerini çözer/kodlar. Saf Dart'tır; Flutter (Android, iOS, masaüstü) ve sunucu tarafında çalışır.

• GoogleMapsPolyline().getRouteBetweenCoordinates(apiKey, başlangıç, hedef, ...) istisna fırlatmaz; result.isSuccess, result.status (API'nin durumu ya da ağ/zaman aşımı/okuma hatasında "error") ve result.errorMessage (API anahtarı maskelenir) kontrol edilir. Uygulama mantığını dilden bağımsız olan status'a göre kurun.
• Dil: Mesajlar varsayılan olarak İngilizcedir. Türkçe için GoogleMapsPolyline(language: 'tr') kullanın; bu değer Directions API'ye de gönderilir, böylece Google'ın hata mesajı da Türkçe gelir.
• detailedPolyline: true, sadeleştirilmiş overview_polyline yerine adım adım ayrıntılı rotayı döndürür.
• PolylineCodec.decode(dize, precision: 5) / PolylineCodec.encode(noktalar, precision: 5); geçersiz dizede FormatException fırlatılır.
• Flutter web: Directions web servisi CORS izni vermediğinden rota isteği tarayıcıda çalışmaz; rotayı kendi sunucunuzda alıp polyline'ı tarayıcıda PolylineCodec.decode ile çözün.
• Anahtar güvenliği: Anahtarı yalnızca Directions API ile sınırlayın ve kota koyun ya da isteği kendi sunucunuzdan yapın.
• Directions API Google tarafından Legacy olarak işaretlendi; yeni projeler için Routes API önerilir.

License / Lisans

MIT — see LICENSE.