CODEWITHSUNDEEP
flutterinheritance
Mauvia Modi
Mauvia Modi

Reputation: 77

Can't get InheritedWidget to work with StatefulWidget

In this code, I want to be able to access accountID and scopeID of the InheritedWidget class further down the line. To test this, I wrote the following code:

import 'package:flutter/material.dart';

class AdvisorContext extends InheritedWidget {
  final int accountId;
  final int scopeId;

  AdvisorContext({key, this.accountId, this.scopeId, child})
      : super(key: key, child: child);

  @override
  bool updateShouldNotify(AdvisorContext oldWidget) {
    return oldWidget.accountId != accountId || oldWidget.scopeId != scopeId;
  }
}

class AdvisorListingView extends StatefulWidget {
  static AdvisorContext of(BuildContext context) =>
      context.dependOnInheritedWidgetOfExactType() as AdvisorContext;

  const AdvisorListingView({Key key, this.child}) : super(key: key);

  final Widget child;

  @override
  State<StatefulWidget> createState() {
    return _AdvisorListingState();
  }
}

class _AdvisorListingState extends State<AdvisorListingView> {
  int accountId;
  int scopeId;

  @override
  Widget build(BuildContext context) {
    return AdvisorContext(
      accountId: accountId,
      scopeId: scopeId,
      child: SafeArea(
        child: Scaffold(
          backgroundColor: Colors.white,
          appBar: AppBar(
            backgroundColor: Color.fromARGB(255, 33, 43, 54),
            elevation: 0,
            title: Text(
              "Chennai",
              style: TextStyle(
                fontFamily: "Roboto",
                fontSize: 16.0,
              ),
            ),
          ),
          body: AdvisorBody(),
        ),
      ),
    );
  }
}

class AdvisorBody extends StatelessWidget {

  @override
  Widget build(BuildContext context) {
    return new AdvisorCard();
  }
}

class AdvisorCard extends StatelessWidget {

  @override
  Widget build(BuildContext context) {
    final advisorContext = AdvisorContext.of(context);
  }
}

I expect that in the AdvisorCard class, I would be able to create the "final advisorContext" variable and then use it to access scopeID and accountID. However, AdvisorContext.of(context) gives the error: "The method 'of' isn't defined for the type AdvisorContext".

How do I get accountID and ScopeID, and when can I assign values to them?

Upvotes: 1

Views: 496

Answers (1)

Blasanka
Blasanka

Reputation: 22437

Congratulation! Almost there. Just add below method to your InheritedWidget:

  static AdvisorContext of(BuildContext context) {
    return context.dependOnInheritedWidgetOfExactType<AdvisorContext>();
  }

.of(context):

The convention is to provide a static method of on the InheritedWidget which does the call to BuildContext.dependOnInheritedWidgetOfExactType. This allows the class to define its own fallback logic in case there isn't a widget in scope. In the example above, the value returned will be null in that case, but it could also have defaulted to a value.

Please read more here.

Upvotes: 1

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