Flutter passing icon parameter as constructor

Question

This is the page of my setting menu widget page or code

class Setting extends StatelessWidget {
  Setting(this.title);

  String title;


  @override
  Widget build(BuildContext context) {
     return Scaffold(
        appBar: AppBar(
        title: Text(title),
        backgroundColor: Theme.of(context).primaryColor,
       ),
     body: Column(
     children: <Widget>[
      setttingWidget(Icons.favorite),
     ],
   )
  );
 }
}

And this is settingWidget page or code :

class setttingWidget extends StatelessWidget {

  setttingWidget(IconData next);

  var next;

  @override
  Widget build(BuildContext context) {
    return Card(
      child: Row(
        children: <Widget>[
          Icon(next),
          Text("Network Setting",
          style: TextStyle(
            fontSize: 20
          ),)
        ],
      ),
    );
  }
}

I want set the icon image from the setting Widget, so use icon data but no icon is appear in app, there the code also show no error at all.

Madhavam Shahi · Accepted Answer · 2020-08-28 05:50:45Z

7

Do it like this,

class Setting extends StatelessWidget {

final title;
  Setting({this.title});

  


  @override
  Widget build(BuildContext context) {
     return MaterialApp(home:Scaffold(
        appBar: AppBar(
        title: Text(title),
        backgroundColor: Theme.of(context).primaryColor,
       ),
     body: Column(
     children: <Widget>[
      setttingWidget(Icons.favorite),
     ],
   )
  ));
 }
}

Setting widget-

class setttingWidget extends StatelessWidget {
final IconData next;
  setttingWidget({this.next});

  

  @override
  Widget build(BuildContext context) {
    return Card(
      child: Row(
        children: <Widget>[
          Icon(next),
          Text("Network Setting",
          style: TextStyle(
            fontSize: 20
          ),)
        ],
      ),
    );
  }
}

You have to use final keyword because stateless widgets are immutable, that means they can not change their state.

answered Aug 28, 2020 at 5:50

Madhavam Shahi

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3 Comments

Madhavam Shahi Over a year ago

Please upvote and accept this as the answer if it helped :)

sazin samin Over a year ago

Thank you so much, I got the point. That's is really helpfull.

Madhavam Shahi Over a year ago

Glad it worked, happy coding! :)

Lapa Ny Aina Tanjona · Accepted Answer · 2020-08-28 06:30:40Z

You can try my code below :

class Setting extends StatelessWidget {
  Setting(this.title);

  final String title;

  @override
  Widget build(BuildContext context) {
     return Scaffold(
        appBar: AppBar(
        title: Text(title),
        backgroundColor: Theme.of(context).primaryColor,
       ),
     body: Column(
     children: <Widget>[
      setttingWidget(Icons.favorite),
     ],
   )
  );
 }
}

class setttingWidget extends StatelessWidget {
  final IconData next;
  
  setttingWidget(this.next);

  @override
  Widget build(BuildContext context) {
    return Card(
      child: Row(
        children: <Widget>[
          Icon(next),
          Text("Network Setting",
          style: TextStyle(
            fontSize: 20
          ),)
        ],
      ),
    );
  }
}

Note : If a widget is stateless, one or more of its instance fields must be final. So,

Change this :

var next;

to

final IconData next;

Output :

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Flutter passing icon parameter as constructor

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