amap_location/lib/amap_location.dart

import 'dart:async';
import 'dart:convert';

import 'package:amap_location/location_option.dart';
import 'package:amap_location/location_result_entity.dart';
import 'package:flutter/services.dart';

class AmapLocation {
  static const MethodChannel _channel = const MethodChannel('amap_location');
  static final AmapLocation _instance = AmapLocation();
  static AmapLocation get instance => _instance;

  StreamController _streamController;
  Stream<LocationResultEntity> get locationStream => _streamController.stream;

  static Future<String> get platformVersion async {
    final String version = await _channel.invokeMethod('getPlatformVersion');
    return version;
  }

  Future<void> startLocation({LocationOption options}) async {
    _setLocationCallback();
    return await _channel.invokeMethod(
        'startLocation', options?.toMap() ?? LocationOption().toMap());
  }

  Future<void> disposed() async {
    if (!_streamController.isClosed) {
      await _streamController.close();
    }
    _streamController = null;
    return await _channel.invokeMethod("closeLocation");
  }

  void _setLocationCallback() {
    if (_streamController == null) {
      _streamController = StreamController<LocationResultEntity>.broadcast();
    }
    _channel.setMethodCallHandler(platformCallHandler);
  }

  Future<void> platformCallHandler(MethodCall call) async {
    try {
      if (call.method == "location") {
        LocationResultEntity entity =
            LocationResultEntity().fromJson(jsonDecode(call.arguments));
        _streamController.add(entity);
      }
    } catch (ex) {
      print('Unexpected error: $ex');
    }
  }
}