问题描述
您好，下面的代码使用google_maps_Flutter和location软件包显示了具有用户位置的地图，下面的代码正确显示了具有经度和纬度初始位置的地图，但是当用户从设备启动应用程序时，该位置不会它成为实际的用户之一，但仍停留在初始位置，我该如何解决呢？
import 'dart:async';
import 'package:Flutter/material.dart';
import 'package:google_maps_Flutter/google_maps_Flutter.dart';
import 'package:location/location.dart';
import 'package:MyApp/View/Cantieri/mediterranesn_diet_view.dart'
show MediterranesnDietView;
import 'package:MyApp/View/Cantieri/title_view.dart' show TitleView;
import 'package:MyApp/View/Home_theme.dart';
import 'package:MyApp/View/marcaTempo/FunzionemarcatempoView.dart'
show marcaTempoListView;
//Valori longitudine e latitudine
double longitudine = 12.4818,latitudine = 41.9109;
LatLng _center = LatLng(latitudine,longitudine);
//Recupero e salvataggio dei valori del gps di longitudine e latitudine
Future<void> _getGpsValue() async {
//Instanzio l'oggetto che si occupa di recuperare i dati per la marcatura
var location = new Location();
location.onLocationChanged().listen((LocationData currentLocation) async {
longitudine = currentLocation.longitude;
latitudine = currentLocation.latitude;
_center = LatLng(latitudine,longitudine);
});
Timer(Duration(seconds: 1),() {
print("E' passato 1 secondo");
print("Latitudine: " +
latitudine.toString() +
"\n Longitudine: " +
longitudine.toString());
});
}
class MyDiaryScreen extends StatefulWidget {
const MyDiaryScreen({Key key,this.animationController}) : super(key: key);
final AnimationController animationController;
@override
_MyDiaryScreenState createState() => _MyDiaryScreenState();
}
class _MyDiaryScreenState extends State<MyDiaryScreen>
with TickerProviderStateMixin {
GoogleMapController mapController;
var width;
void _onMapCreated(GoogleMapController controller) {
mapController = controller;
}
List<Widget> listViews = <Widget>[];
final ScrollController scrollController = ScrollController();
Animation<double> topBaranimation;
double topBarOpacity = 0.0;
@override
void initState() {
_getGpsValue();
topBaranimation = Tween<double>(begin: 0.0,end: 1.0).animate(
CurvedAnimation(
parent: widget.animationController,curve: Interval(0,0.5,curve: Curves.fastOutSlowIn)));
addAllListData();
scrollController.addListener(() {
if (scrollController.offset >= 24) {
if (topBarOpacity != 1.0) {
setState(() {
topBarOpacity = 1.0;
});
}
} else if (scrollController.offset <= 24 &&
scrollController.offset >= 0) {
if (topBarOpacity != scrollController.offset / 24) {
setState(() {
topBarOpacity = scrollController.offset / 24;
});
}
} else if (scrollController.offset <= 0) {
if (topBarOpacity != 0.0) {
setState(() {
topBarOpacity = 0.0;
});
}
}
});
super.initState();
}
void addAllListData() {
_getGpsValue();
const int count = 9;
//Prima view che comprende il titolo della Posizione
listViews.add(
TitleView(
titleTxt: 'Posizione',subTxt: '',animation: Tween<double>(begin: 0.0,end: 1.0).animate(CurvedAnimation(
parent: widget.animationController,curve:
Interval((1 / count) * 0,1.0,curve: Curves.fastOutSlowIn))),animationController: widget.animationController,),);
//Inserimento del modulo con le informazioni sulla posizione
listViews.add(
MediterranesnDietView(
animation: Tween<double>(begin: 0.0,curve:
Interval((1 / count) * 1,);
//Inserimento del titolo di registrazione
listViews.add(
TitleView(
titleTxt: 'Registrazione',curve:
Interval((1 / count) * 2,);
//Inserimento dei button per il marcatempo
listViews.add(
marcaTempoListView(
mainScreenAnimation: Tween<double>(begin: 0.0,end: 1.0).animate(
CurvedAnimation(
parent: widget.animationController,curve: Interval((1 / count) * 3,mainScreenAnimationController: widget.animationController,);
//Inserimento del titolo di registrazione
listViews.add(
TitleView(
titleTxt: 'Mappa',);
listViews.add(new Container(
width: width,height: 400.0,child: GoogleMap(
onMapCreated: _onMapCreated,initialCameraPosition: CameraPosition(
target: _center,zoom: 6.0,))));
}
Future<bool> getData(BuildContext context) async {
await Future<dynamic>.delayed(const Duration(milliseconds: 50));
width = MediaQuery.of(context).size.width;
return true;
}
Widget getMainListViewUI() {
return FutureBuilder<bool>(
future: getData(context),builder: (BuildContext context,AsyncSnapshot<bool> snapshot) {
if (!snapshot.hasData) {
return const SizedBox();
} else {
return ListView.builder(
shrinkWrap: true,controller: scrollController,padding: EdgeInsets.only(
top: AppBar().preferredSize.height +
MediaQuery.of(context).padding.top +
24,bottom: 62 + MediaQuery.of(context).padding.bottom,itemCount: listViews.length,scrollDirection: Axis.vertical,itemBuilder: (BuildContext context,int index) {
widget.animationController.forward();
return listViews[index];
},);
}
},);
}
//Recupero della barra per la UI
Widget getAppBarUI() {
return Column(
children: <Widget>[
AnimatedBuilder(
animation: widget.animationController,Widget child) {
return FadeTransition(
opacity: topBaranimation,child: Transform(
transform: Matrix4.translationValues(
0.0,30 * (1.0 - topBaranimation.value),0.0),child: Container(
decoration: Boxdecoration(
color: TemaApp.white.withOpacity(topBarOpacity),borderRadius: const BorderRadius.only(
bottomLeft: Radius.circular(32.0),BoxShadow: <BoxShadow>[
BoxShadow(
color: TemaApp.grey.withOpacity(0.4 * topBarOpacity),offset: const Offset(1.1,1.1),blurRadius: 10.0),],child: Column(
children: <Widget>[
SizedBox(
height: MediaQuery.of(context).padding.top,Padding(
padding: EdgeInsets.only(
left: 16,right: 16,top: 16 - 8.0 * topBarOpacity,bottom: 12 - 8.0 * topBarOpacity),child: Row(
mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[
Expanded(
child: Padding(
padding: const EdgeInsets.all(8.0),child: Text(
'marcatempo',textAlign: TextAlign.left,style: TextStyle(
fontFamily: TemaApp.fontName,fontWeight: FontWeight.w700,fontSize: 22 + 6 - 6 * topBarOpacity,letterSpacing: 1.2,color: TemaApp.darkerText,)
],);
},)
],);
}
@override
Widget build(BuildContext context) {
return Container(
color: TemaApp.background,child: Scaffold(
backgroundColor: Colors.transparent,resizetoAvoidBottomPadding: true,body: Stack(
children: <Widget>[
//getMap(),getMainListViewUI(),getAppBarUI(),SizedBox(
height: MediaQuery.of(context).padding.bottom,)
],);
}
}
解决方法
您需要在setState()内部致电_getGpsValue()来更新用户的位置。
setState(() {
longitudine = currentLocation.longitude;
latitudine = currentLocation.latitude;
_center = LatLng(latitudine,longitudine);
})
调用setState会通知框架内部状态 该对象的更改方式可能会影响用户界面 在此子树中，这将导致框架为 这个State对象。