每次将新元素（位置）添加到数据库时，我都会尝试更新下面的 listView，但只有在我关闭并重新打开应用程序时才会更新，但在用户导航到 LocationHistory 页面时不会更新
class LocationHistory extends StatefulWidget {
@override
_LocationHistoryState createState() => _LocationHistoryState();
}
class _LocationHistoryState extends State<LocationHistory> {
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
leading: new IconButton(
icon: Icon(Icons.arrow_back),
onPressed: () => Navigator.of(context).pop(),
),
title: Text("Saved Locations"),
),
body: Consumer<LocationHistoryModel>(
builder: (context, locationHistoryModel, child){
return ListView.builder(
itemCount: locationHistoryModel.currentUserLocations.length,
itemBuilder: (context, index) =>
Column(
children: <Widget>[
buildListTile(
address: locationHistoryModel
.currentUserLocations[index].address,
createdAt: locationHistoryModel
.currentUserLocations[index].createdAt,
inOut: locationHistoryModel
.currentUserLocations[index].inOut,
),
],
)
);}
),);
}
}
我使用 notifyListeners 通知列表重建自身的 locationHistoryModel
class LocationHistoryModel extends ChangeNotifier{
final locationHistory = LocationHistoryRep();
List currentUserLocations =[];
User _user;
set user(User value) {
_user = value;
}
User get user => _user;
LocationHistoryModel () {
getLocationHistory();
}
getLocationHistory() async{
var locationsHistory = await locationHistory.getAllSavedLocations();
List allUsersLocations = locationsHistory["data"] ;
for(int i =0; i<allUsersLocations.length;i++){
if(allUsersLocations[i]["userId"]==_user.id){
currentUserLocations.add(LocationElement.fromJson(allUsersLocations[i]));
}
}
notifyListeners();
return currentUserLocations;
}
setLocation({String address, String inOut}) async{
await locationHistory.addCurrentLocation(address: address,inOut: inOut,userId: _user.id);
notifyListeners();
}
当我导航到列表时，我尝试在此处更新列表的小部件未找到任何更改
class MyHomePage extends StatefulWidget {
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
GoogleMapController mapController;
void _onMapCreated(GoogleMapController controller) {
mapController = controller;
}
@override
void initState() {
super.initState();
Provider.of<AuthModel>(context, listen: false).getUser();
}
@override
Widget build(BuildContext context) {
Size size = MediaQuery.of(context).size;
final location = Provider.of<Location>(context);
final locationHistory = Provider.of<LocationHistoryModel>(context);
return location.currentLocation == null ? Scaffold(body: CircularIndicator()): Scaffold(
appBar: AppBar(
centerTitle: true,
backgroundColor: Colors.orange,
title: Center(child: Text('Remote Tracker')),
),
),
floatingActionButton: new FloatingActionButton(
backgroundColor: Colors.orange,
child: const Icon(Icons.location_on),
onPressed: () async{
showDialog(context: context,
builder: (BuildContext context){
return AdvanceCustomAlert(
location.address,
() async{
await locationHistory.setLocation(address: location.address,inOut: "out");
Navigator.of(context).push(MaterialPageRoute(
builder: (context) => LocationHistory(),
// here when navigating to LocationHistory the list is not updating
));
},
() async{
await locationHistory.setLocation(address: location.address,inOut: "in");
Navigator.of(context).pop();
},
);
}
);// Add your onPressed code here!
},
),
floatingActionButtonLocation:
FloatingActionButtonLocation.centerFloat,
bottomNavigationBar: new BottomAppBar(
color: Colors.white,
),
body: Container(
width: size.width,
height: size.height,
child: Stack(
alignment: Alignment.centerRight,
children: <Widget>[
GoogleMap(
onMapCreated: _onMapCreated,
myLocationEnabled: true,
initialCameraPosition: CameraPosition(
target: LatLng(location.currentLocation.latitude,location.currentLocation.longitude),
zoom: 14.0,
),
),
],
),
),
);
}
}