Pass parameter to initState

Question

Look at this code - widget to fetch data and display on list:

class _MyEventsFragmentState extends State <MyEventsFragment>{

  var events;

  @override
  initState(){
    super.initState();
    events = fetchEvents(true);
  }

  @override
  Widget build(BuildContext context) {
    return new Center(
        child: FutureBuilder<EventsResponse>(
          future: events,
          builder: (context, snapshot) {
            if (snapshot.connectionState == ConnectionState.done) {
              if (snapshot.hasError) {
                helpers.logout(context, Strings.msg_session_expired);
                return CircularProgressIndicator();
              }
              return new Container(color: Colors.white,
                  child: new ListControl().build(snapshot));
            }
            return CircularProgressIndicator();
          },
        )
    );
  }
}

fetchEvent method has parameter to indicate which events I need to fetch. If set to true, - my events, if set to false - all events returned. Above code loads my events and fetchEvents is called inside initState override to avoid unnecesary data reloading.

To fetch all events I defined another class:

class EventsFragment extends StatefulWidget {

  @override
  _EventsFragmentState createState() => new _EventsFragmentState();
}

class _EventsFragmentState extends State <EventsFragment>{

  var events;

  @override
  initState(){
    super.initState();
    events = fetchEvents(false);
  }

  @override
  Widget build(BuildContext context) {
    return new Center(
        child: FutureBuilder<EventsResponse>(
          future: events,
          builder: (context, snapshot) {
            if (snapshot.connectionState == ConnectionState.done) {
              if (snapshot.hasError) {
                helpers.logout(context, Strings.msg_session_expired);
                return CircularProgressIndicator();
              }
              return new Container(color: Colors.white,
                  child: new ListControl().build(snapshot));
            }
            return CircularProgressIndicator();
          },
        )
    );
  }
}

But this is very dumb solution, because code is almost the same. So I tried to pass boolean value to indicate which events to load, something like that:

@override
  initState(){
    super.initState();
    events = fetchEvents(isMyEvents);
  }

isMyEvents should be got from EventsFragment constructor. However, it won't be accesible inside initState. Ho to pass it properly? I could access it inside build override, but not inside initState. How to pass it properly and make sure it will be refreshed every time widget instance is created?

[edit]

So this how I solved my problem (it seems to be fine):

class EventsFragment extends StatefulWidget {
  const EventsFragment({Key key, this.isMyEvent}) : super(key: key);

  final bool isMyEvent;

  @override
  _EventsFragmentState createState() => new _EventsFragmentState();
}

class _EventsFragmentState extends State <EventsFragment>{

  var events;

  @override
  initState(){
    super.initState();
    events = fetchEvents(widget.isMyEvent);
  }

  @override
  void didUpdateWidget(EventsFragment oldWidget) {

    if(oldWidget.isMyEvent != widget.isMyEvent)
      events = fetchEvents(widget.isMyEvent);

    super.didUpdateWidget(oldWidget);
  }

  @override
  Widget build(BuildContext context) {
    return new Center(
        child: FutureBuilder<EventsResponse>(
          future: events,
          builder: (context, snapshot) {
            if (snapshot.connectionState == ConnectionState.done) {
              if (snapshot.hasError) {
                helpers.logout(context, Strings.msg_session_expired);
                return CircularProgressIndicator();
              }
              return new Container(color: Colors.white,
                  child: new ListControl().build(snapshot));
            }
            return CircularProgressIndicator();
          },
        )
    );
  }
}

Answer 1

Pass such parameter to the StatefulWidget subclass, and use that field instead

class Foo extends StatefulWidget {
  const Foo({Key key, this.isMyEvent}) : super(key: key);

  final bool isMyEvent;

  @override
  _FooState createState() => _FooState();
}

class _FooState extends State<Foo> {
  @override
  void initState() {
    super.initState();
    print(widget.isMyEvent);
  }

  @override
  Widget build(BuildContext context) {
    return Container(

    );
  }
}