颤振 - 启用位置并将摄像机动画化到当前位置

Question

我的目标写在上面的标题中。

当我尝试使用已经启用了位置的应用程序时，给定的功能运行良好。 但是当我尝试禁用位置时，它要求我打开位置，所以我打开了它，但该功能不起作用。

我正在从 initState(( 调用我的函数。

firstLocation() async {
await location.getLocation().then((LocationData locationData){
//Sets the changing location in the Map Controller
LatLng latLng = new LatLng(locationData.latitude, locationData.longitude);
CameraUpdate cameraUpdate = CameraUpdate.newLatLngZoom(latLng, 15);
mapController.animateCamera(cameraUpdate);
});
}

@override
void initState() {
super.initState();
firstLocation();
}

如果你想看整个类代码：

class UserMapState extends State<UserMap> {
GoogleMapController mapController;
// Location location = new Location();
Map<PolylineId, Polyline> _mapPolylines = {};
int _polylineIdCounter = 1;
final List<LatLng> points = <LatLng>[];
Set<Marker> _markers = {};
LatLng _lastMapPosition; // CLASS MEMBER, MAP OF MARKS
bool driver_status = false;
bool pick_request = false;
GeoFirePoint _driverCurrentLocation;        
Geoflutterfire geo = Geoflutterfire();
var firestore = Firestore.instance;
BitmapDescriptor myIcon;
BorderRadiusGeometry radius;
var location = new Location();
//   getDeviceLocation() async {
//     LocationData currentLocation;
//     try {
//       currentLocation = await location.getLocation();
//       print("locationLatitude: ${currentLocation.latitude}");
//       print("locationLongitude: ${currentLocation.longitude}"); 
//       setState(() {
//        this.latitude_current = currentLocation.latitude;
//        this.longitude_current = currentLocation.longitude;  
//       });
//  //rebuild the widget after getting the current location of the user
//     } on Exception {
//       currentLocation = null;
//     }
//   }
getRoute() {
firestore
.collection(widget.institute)
.document(widget.bus)
.collection('Route')
.orderBy('serial')
.snapshots()
.listen(
(snap)  => snap.documents.forEach((doc){
print(doc.data['LatLng'].latitude.toString());
points.add(LatLng(doc.data['LatLng'].latitude, doc.data['LatLng'].longitude));                   
}),
);
}
firstLocation() async {
location.getLocation().then((LocationData locationData){
//Sets the changing location in the Map Controller
LatLng latLng = new LatLng(locationData.latitude, locationData.longitude);
CameraUpdate cameraUpdate = CameraUpdate.newLatLngZoom(latLng, 15);
mapController.animateCamera(cameraUpdate);
});
}
pickupRequest(bool value) async {
var pos = await location.getLocation();
GeoFirePoint point  = geo.point(latitude: pos.latitude, longitude: pos.longitude);
firestore.collection(widget.institute).document(widget.bus).collection('Users').document(widget.uid).setData({
'position': point.data,
'pickup': value,
});
}
@override
void initState() {
super.initState();
getRoute();
firstLocation();
BitmapDescriptor.fromAssetImage(
ImageConfiguration(size: Size(48, 48)), 'assets/bus_icon.png')
.then((onValue) {
myIcon = onValue;
});
radius = BorderRadius.only(
topLeft: Radius.circular(12.0),
topRight: Radius.circular(12.0),
);
}

@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Nomad"),
),
drawer: DrawerWidget(name: widget.name, userID: widget.userID, institute: widget.institute,),
body: SlidingUpPanel(
panel: StreamBuilder(
stream: firestore.collection(widget.institute.toString()).document(widget.bus.toString()).collection("Driver").snapshots(),
builder: (context, snap) {
if(snap.hasData) {
List<DocumentSnapshot> snapshot = snap.data.documents;
if(snapshot[0]['session'] == 1)
{
_lastMapPosition = LatLng(snapshot[0]['location']['geopoint'].latitude, snapshot[0]['location']['geopoint'].longitude);
print(snapshot[0]['location']['geopoint'].latitude.toString());
this._driverCurrentLocation = geo.point(latitude: snapshot[0]['location']['geopoint'].latitude, longitude: snapshot[0]['location']['geopoint'].longitude);
print(_driverCurrentLocation.data['geopoint'].latitude.toString() + " " + _driverCurrentLocation.data['geopoint'].longitude.toString());
this.driver_status = true;
_getDriverMarker(_driverCurrentLocation.data['geopoint'].latitude, _driverCurrentLocation.data['geopoint'].longitude);
return Container(
child: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Center(
child: Text(
"Driver Name : " + snapshot[0]['name'] + "n" + "Contact Driver : " + snapshot[0]['contact'],
textAlign: TextAlign.center,
style: TextStyle(color: Colors.black, fontSize: 24.0, fontWeight: FontWeight.w300)
),
),
],
),
),
);
} else {
this.driver_status = false;
_getDriverMarker(0.0, 0.0);
return Container(
child: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Center(
child: Text(
"Driver Name : " + snapshot[0]['name'] + "n" + "Contact Driver : " + snapshot[0]['contact'],
textAlign: TextAlign.center,
style: TextStyle(color: Colors.black, fontSize: 24.0, fontWeight: FontWeight.w300)
),
),
],
),
),
);
}
} else {
return Container(
child: Center(child: CircularProgressIndicator(),),
);
}
},
),
collapsed: Container(
decoration: BoxDecoration(
color: Colors.white,
borderRadius: radius,
),
child: Center(
child: driver_status == true ?
Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
"Driver Online",
style: TextStyle(color: Colors.black, fontSize: 24.0, fontWeight: FontWeight.w300),
),
StreamBuilder(
stream: firestore.collection(widget.institute).document(widget.bus).collection('Users').document(widget.uid).snapshots(),
builder: (context, snap) {
if(snap.hasData) {
if(snap.data['pickup'] == false) {
return MaterialButton(
child: Text(
"Pickup", 
textAlign: TextAlign.center,
style: TextStyle(color: Colors.white, fontSize: 24.0, fontWeight: FontWeight.w300)
),
color: Colors.blueAccent,
onPressed: () {
_addPickupMarker();
},
);
} else {
return MaterialButton(
child: Text(
"I am Riding", 
textAlign: TextAlign.center,
style: TextStyle(color: Colors.white, fontSize: 24.0, fontWeight: FontWeight.w300)
),
color: Colors.blueAccent,
onPressed: () {
_removePickupMarker();
},
);
}
} else {
return CircularProgressIndicator(backgroundColor: Colors.blueAccent,);
}
},
),
],
) :
Text(
"Driver Offline",
style: TextStyle(color: Colors.black, fontSize: 24.0, fontWeight: FontWeight.w300),
),
),
),
body: Stack(
children: <Widget>[
GoogleMap(
initialCameraPosition: CameraPosition(
target: LatLng(26.9124, 75.7873),
zoom: 12
),
rotateGesturesEnabled: true,
compassEnabled: true,
onMapCreated: _onMapCreated,
myLocationEnabled: true,
myLocationButtonEnabled: true,
mapType: MapType.normal,
polylines: Set<Polyline>.of(_mapPolylines.values),
markers: _markers,
),
],
),
backdropEnabled: true,
borderRadius: radius,
)
);
}
void _add() {
final String polylineIdVal = 'polyline_id_$_polylineIdCounter';
_polylineIdCounter++;
final PolylineId polylineId = PolylineId(polylineIdVal);
final Polyline polyline = Polyline(
polylineId: polylineId,
consumeTapEvents: true,
color: Colors.grey,
width: 10,
points: points,
);
setState(() {
_mapPolylines[polylineId] = polyline;
});
}
_getDriverMarker(lat, long) async{
if(driver_status == true) {
SchedulerBinding.instance.addPostFrameCallback((_) => setState(() {
this._markers.clear();
this._markers.add(Marker(
markerId: MarkerId(_lastMapPosition.toString()),
icon: myIcon,
position: LatLng(lat, long),
)); 
}));
} else {
SchedulerBinding.instance.addPostFrameCallback((_) => setState(() {
this._markers.clear();  
}));
}
}
void _addPickupMarker() {
SchedulerBinding.instance.addPostFrameCallback((_) => setState(() {
// this._markers.add(Marker(
//   markerId: MarkerId('1'),
//   icon: BitmapDescriptor.defaultMarker,
//   position: LatLng(latitude_current, longitude_current),
// ));
this.pick_request = true;
pickupRequest(true); 
}));
}
void _removePickupMarker() {
SchedulerBinding.instance.addPostFrameCallback((_) => setState(() {
// this._markers.remove(Marker(
//     markerId: MarkerId('1'),
//     icon: BitmapDescriptor.defaultMarker,
//     position: LatLng(latitude_current, longitude_current),
// ));
this.pick_request = false;
pickupRequest(false); 
}));
}
_onMapCreated(GoogleMapController controller) {
_add();
setState(() {
mapController = controller;
});
}
}

Answer 1

如果您使用的是位置插件，则可以在每次用户更改其位置时获取位置流

LatLng userPosition;
location.onLocationChanged().listen((LocationData position) {
setState(() {
userPosition = LatLng(position.latitude, position.longitude);
});
});

然后，您可以在每次位置更改时对摄像机进行动画处理

final GoogleMapController controller = await _controller.future;
controller.animateCamera(
CameraUpdate.newCameraPosition(
CameraPosition(target: userPosition, zoom: zoomValue),
),
);

Answer 2

查看以下示例/教程：

https://flutterbyexample.com/make-the-static-map-interactive/