AMapFlutterLocation的回调方法转为异步操作

 用Completer实现

class LocationInfo{
  double longitude;
  double latitude;
  String address;

  LocationInfo({this.latitude, this.longitude,this.address});

}

class LocationUtil{

  ///界面初始化完成
  static Future<LocationInfo> fetchLocation() async {
    Completer<LocationInfo> completer = Completer();

    AMapFlutterLocation.updatePrivacyShow(true, true);
    AMapFlutterLocation.updatePrivacyAgree(true);
    AMapFlutterLocation.setApiKey("android ApiKey", "a6b2356c68aac3fdabd7ecdce63c2130");
    AMapFlutterLocation amapLocation = AMapFlutterLocation();

    AMapLocationOption locationOption = new AMapLocationOption();
    locationOption.onceLocation = true;
    amapLocation.setLocationOption(locationOption);

    //amapLocation.onLocationChanged().listen((Map<String, Object> result) {
    amapLocation.onLocationChanged().listen((Map<String, Object> result) {
      if (result != null) {

        double longitude = double.tryParse(result['longitude']);
        double latitude = double.tryParse(result['latitude']);
        String address = result['address'];

        LocationInfo locationInfo = LocationInfo(longitude:longitude,latitude:latitude,address:address,);

        if (!completer.isCompleted) {
          completer.complete(locationInfo);
        }
      }
    });

    amapLocation.startLocation();


    return completer.future;
  }

}

调用：

  ///开始定位
  void _startLocation() async{
    LocationInfo locationInfo  = await LocationUtil.fetchLocation();
    print('LocationInfo: ${locationInfo.address} ${locationInfo.latitude}');
  }