Flutter - Loading (Empty) List from Provider-CodePudding

in my app I want to load events from the database. My problem is: If the user does not have any events stored, the "getAll"-Function i created (to add events from my database) is called non-stop. How can I make a better implementation?

Abstract from my provider:

class EventProvider extends ChangeNotifier {
  List<Events> _events = [];
  List<Events> get events => _events;

 getAllEvents() async {
    Datenbank DBprovider = Datenbank();
    final data = await Datenbank.getAllTermine();
    for (var i = 0; i < data.length; i  ) {
      _events.add(data[i]);
    }
    notifyListeners();
  }

My app code:

  @override
  Widget build(BuildContext context) {
    final provider = Provider.of<EventProvider>(context, listen: true);
    events = Provider.of<EventProvider>(context).events;

    //I created this "if" in order to load the event-List for the first time 
    //and get all items (i guess, that this is total ineffcient)
    //also, if there are no events this function is called endlessly and rebuilds
    //everything on and on and on....
    if (events.isEmpty) {
      provider.getAllEvents();
    }

thanks for help!

CodePudding user response：

You can call method once widget is created. Make your widget StatefulWidget

@override
void initState() {
  super.initState();
  final provider = Provider.of<EventProvider>(context, listen: false);
  provider.getAllEvents();
}

@override
Widget build(BuildContext context) {
  final provider = Provider.of<EventProvider>(context, listen: true);
  ...
}