I'm trying to do a search in my application and I'm using this SearchDelegate for that. Previously, when I used a provider, everything worked, but I had to make serious changes in the code and now this algorithm below is responsible for finding routes. I am trying to put RouteWithStops in SearchDelegate, and after that to use FutureBuilder inside Widget buildSuggestions. So the code is like this:
The algorithm for searching routes with stops with dart models:
Future<List<RouteWithStops>> getMarshrutWithStops(int ttId) async {
if (routesbyTransportType.isEmpty) {
await fetchTransportWithRoutes();
}
List<Routes> routes = routesbyTransportType[ttId].routes;
List<ScheduleVariants> variants = [];
variants.addAll(await api.fetchSchedule());
List<RouteWithStops> routesWithStops = [];
for (Routes route in routes) {
final routeWithStops = RouteWithStops();
routesWithStops.add(routeWithStops);
routeWithStops.route = route;
routeWithStops.variant =
variants.where((variant) => variant.mrId == route.mrId).first;
}
return routesWithStops;
}
Future<RouteWithStops> fetchStopsInfo(routeWithStops) async {
List<RaceCard> cards = [];
List<StopList> stops = [];
cards.addAll(await api.fetchRaceCard(routeWithStops.variant.mvId));
stops.addAll(await api.fetchStops());
print(cards);
List<StopList> currentRouteStops = [];
cards.forEach((card) {
stops.forEach((stop) {
if (card.stId == stop.stId) {
currentRouteStops.add(stop);
}
});
});
routeWithStops.stop = currentRouteStops;
return routeWithStops;
}
}
the models:
@HiveType(typeId: 0)
class RouteWithStops {
@HiveField(0)
Routes route;
@HiveField(1)
List<StopList> stop;
@HiveField(2)
List<RaceCard> cards;
@HiveField(3)
ScheduleVariants variant;
@HiveField(4)
Transport transport;
}
The SearchDelegate which I want to use to search in a list of routes, the single route I want:
class SearchBar extends SearchDelegate<RouteWithStops> {
final int ttId;
final RouteWithStops routeWithStops;
TransportService service = getIt<TransportService>();
SearchBar({this.ttId, this.routeWithStops});
@override
List<Widget> buildActions(BuildContext context) {
return [
IconButton(
icon: Icon(Icons.clear),
onPressed: () {
query = '';
})
];
}
@override
Widget buildLeading(BuildContext context) {
return IconButton(
icon: AnimatedIcon(
icon: AnimatedIcons.menu_arrow,
progress: transitionAnimation,
),
onPressed: () {
close(context, null);
});
}
@override
Widget buildResults(BuildContext context) {
return FutureBuilder(
future: service.getMarshrutWithStops(ttId),
builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) {
List<RouteWithStops> routes = snapshot.data;
List<RouteWithStops> routes = [];
List<RouteWithStops> recentRoutes = [];
final suggestion = query.isEmpty
? recentRoutes
: routes
.where((element) => element.route.mrTitle.startsWith(query))
.toList();
print(routes?.toString());
return (routes == null)
? Center(child: CircularProgressIndicator())
: ListView.builder(
itemCount: suggestion.length,
itemBuilder: (context, index) {
return ListTile(
title: RichText(
text: TextSpan(
text: suggestion[index]
.route
.mrTitle
.substring(0, query.length),
style: TextStyle(
color: Colors.black, fontWeight: FontWeight.bold),
),
),
);
});
});
}
@override
Widget buildSuggestions(BuildContext context) {
return FutureBuilder(
future: service.getMarshrutWithStops(ttId),
builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) {
List<RouteWithStops> routes = snapshot.data;
List<RouteWithStops> recentRoutes = [];
final suggestion = query.isEmpty
? recentRoutes
: routes
.where((element) => element.route.mrTitle.startsWith(query))
.toList();
print(routes?.toString());
return (routes == null)
? Center(child: CircularProgressIndicator())
: ListView.builder(
itemCount: suggestion.length,
itemBuilder: (context, index) {
return ListTile(
title: RichText(
text: TextSpan(
text: suggestion[index]
.route
.mrTitle
.substring(0, query.length),
style: TextStyle(
color: Colors.black, fontWeight: FontWeight.bold),
),
),
);
});
});
}
}
When i am trying to serach an item in items I get the progress indicator and after I trying to type one letter my app crushes and I got this error:
The method 'where' was called on null.
Receiver: null
Tried calling: where(Closure: (RouteWithStops) => bool)
I understand that this error is pretty straightforward and it sayas that something is null inside that algorithm, but I use this algo in the whole app and everything works fine without any errors. But may be I think wrongly in using SearchDelegate. Can somebody, please, help me?
