如何在flutter中从firestore的地图上显示标记？答案

【问题标题】：How to show Markers on the map from firestore in flutter?如何在flutter中从firestore的地图上显示标记？
【发布时间】：2020-03-31 01:43:52
【问题描述】：

我正在尝试在 firestore 的地图上显示标记，并且我使用了谷歌地图颤振插件，但标记没有显示在地图上。我试图在模拟器和 Android 手机上运行该应用程序。请帮忙。

这是代码：

  @override
void initState() {
super.initState();
populateClients();
Geolocator().getCurrentPosition().then((currloc) {
  setState(() {
    currentLocation = currloc;
  });
});
}

 populateClients() async {
var pos = await Geolocator().getCurrentPosition();
final coordinates = new coder.Coordinates(
    pos.latitude, pos.longitude);
var addresses = await coder.Geocoder.local.findAddressesFromCoordinates(
    coordinates);
var first = addresses.first;
initializeDateFormatting();
var format = DateFormat.d('ar');
var dateString = format.format(DateTime.now());
final FirebaseUser user = await _auth.currentUser();
final uid = user.uid;
Firestore.instance.collection('profiles')
      .where('City', isEqualTo: first.locality)
      .where('Days', arrayContains: dateString)
      .where('Uid' != uid)
      .where('role' == 'user')
    .getDocuments().then((docs) {
  if (docs.documents.isNotEmpty) {
    for (int i = 0; i < docs.documents.length; i++) {
      clients.add(docs.documents[i].data);
      initMarker(docs.documents[i].data,
          docs.documents[i].documentID);
    }
  }
});
}

void initMarker(client, markerRef) {
var markerIdVal = markerRef;
final MarkerId markerId = MarkerId(markerIdVal);


  final Marker marker = Marker(
    markerId: markerId,
    position: LatLng(double.parse(client['Location'].latitude),
        double.parse(client['Location'].longitude)),
    infoWindow: InfoWindow(title: "click here", snippet: "click to show the details"),
    icon: BitmapDescriptor.defaultMarker,
    onTap: () {
      showAlertDialog(client);
    }
);

setState(() {
// adding a new marker to map
markers[markerId] = marker;
});
}

代码有什么错误？

【问题讨论】：

标签： google-maps flutter dart

【解决方案1】：

Map<MarkerId, Marker> markers = <MarkerId, Marker>{};

populateClients(){  
Firestore.instance
.collection('victims')
.getDocuments()
.then((docs){
  if(docs.documents.isNotEmpty){
    for(int i=0; i<docs.documents.length;i++){
    initMarker(docs.documents[i].data, docs.documents[i].documentID);
    }
  }

} ); }

void initMarker(request, requestId){

var p=request['position'];
var markerIdVal= requestId;
final MarkerId markerId= MarkerId(markerIdVal);
final Marker marker= Marker(
  markerId:  markerId,
  position: LatLng(p['geopoint'].latitude, p['geopoint'].longitude),
  infoWindow: InfoWindow (title: request['name'],snippet: request['address']),
);
setState(() {
  markers[markerId]=marker;
  
}); }

【讨论】：