我需要在后台加载地图,因为当我第一次点击包含maps.dart的选项卡时,地图正在加载。这看起来很糟糕,所以我想使用FutureBuilder来显示CircularProgressIndicator(),但我不知道该怎么做。
我知道如何对列表进行操作,但在这种情况下......
这是maps.dart代码:
这是maps.dart代码:
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:font_awesome_flutter/font_awesome_flutter.dart';
class Maps extends StatefulWidget {
@override
_MapsState createState() => _MapsState();
}
class _MapsState extends State<Maps> with AutomaticKeepAliveClientMixin {
Completer<GoogleMapController> _controller = Completer();
@override
void initState() {
super.initState();
}
double zoomValue = 9.0;
@override
Widget build(BuildContext context) {
super.build(context);
return Scaffold(
body: Stack(
children: <Widget>[
_buildGoogleMap(context),
_zoomMinusFunction(),
_zoomPlusFunction(),
],
),
);
}
Widget _zoomMinusFunction() {
return Align(
alignment: Alignment.topLeft,
child: IconButton(
icon: Icon(FontAwesomeIcons.searchMinus, color: Color(0xff6200ee)),
onPressed: () {
zoomValue--;
_minus(zoomValue);
}),
);
}
Widget _zoomPlusFunction() {
return Align(
alignment: Alignment.topRight,
child: IconButton(
icon: Icon(FontAwesomeIcons.searchPlus, color: Color(0xff6200ee)),
onPressed: () {
zoomValue++;
_plus(zoomValue);
}),
);
}
Future<void> _minus(double zoomValue) async {
final GoogleMapController controller = await _controller.future;
controller.animateCamera(CameraUpdate.newCameraPosition(
CameraPosition(target: LatLng(x, y), zoom: zoomValue)));
}
Future<void> _plus(double zoomValue) async {
final GoogleMapController controller = await _controller.future;
controller.animateCamera(CameraUpdate.newCameraPosition(
CameraPosition(target: LatLng(x, y), zoom: zoomValue)));
}
Widget _buildGoogleMap(BuildContext context) {
return Container(
height: MediaQuery.of(context).size.height,
width: MediaQuery.of(context).size.width,
child: GoogleMap(
mapType: MapType.normal,
initialCameraPosition:
CameraPosition(target: LatLng(x, y), zoom: 9),
onMapCreated: (GoogleMapController controller) {
_controller.complete(controller);
},
markers: {
aaa,
bbb,
},
),
);
}
@override
bool get wantKeepAlive => true;
}
Marker aaa = Marker(
markerId: MarkerId('aaa'),
position: LatLng(x, y),
infoWindow: InfoWindow(title: 'aaa', snippet: 'aaa'),
icon: BitmapDescriptor.defaultMarkerWithHue(
BitmapDescriptor.hueViolet,
),
);
Marker bbb = Marker(
markerId: MarkerId('bbb'),
position: LatLng(x, y),
infoWindow:
InfoWindow(title: 'bbb', snippet: 'bbb'),
icon: BitmapDescriptor.defaultMarkerWithHue(
BitmapDescriptor.hueViolet,
),
);
对不起,我对Flutter还不太熟悉。