CODEWITHSUNDEEP
androiddartflutterstatefulwidget
Damien
Damien

Reputation: 1218

Stateful widget in Scaffold's body

I don't understand why in flutter is not possible to have a structure like this:

//...
Scaffold(
  //...
  body: myPage(dataList[index])
)
//...

Where myPage is a class that extends statefulWidget and returns a ListView. It requires a data parameter that is stored in an array. I want to change the body of my scaffold when I change the index for example with a navigation drawer.

I noticed that:

And Yes, I used the setState method to refresh the layout whenever I change the index.

Is this a bug or I missed something? If it is not a bug, what could I do as workaround? Thanks in advance

UPDATE:

I post the code of another page that is simpler with nothing strange where there is anyway this problem (I know in this page I could use a statelessWidget but it should work anyway):

class FirstFragment extends StatefulWidget {
  String data;
  FirstFragment(this.data);

  @override
  _FirstFragment createState() => new _FirstFragment(data);

}

class _FirstFragment extends State<FirstFragment>{
  String data;
  _FirstFragment(this.data);

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return new Center(
      child: new Text(data),
    );
  }
}

Upvotes: 1

Views: 1915

Answers (1)

Amarok
Amarok

Reputation: 472

You shouldn't pass parameters from parent widget class to its state - you can access them thru "widget" directive. Also, listen to Lint - all instances should be final in the main class.

class FirstFragment extends StatefulWidget {
  final String data;
  FirstFragment(this.data);

  @override
  _FirstFragment createState() => new _FirstFragment();

}

class _FirstFragment extends State<FirstFragment>{


  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return new Center(
      child: new Text(widget.data),
    );
  }
}

Upvotes: 2

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