Why can't I take in a variable for title in flutter?

Question

In flutter you can't set the title variable to test because Text would not be constant.

class StockCard extends StatelessWidget {

  String test;

  StockCard(String t) {
    test = t;
  }

  @override
  Widget build(BuildContext context) {
    return (
      new Container(
        margin: const EdgeInsets.all(10.0),
        child: new Card(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: <Widget>[
              const ListTile(
                leading: Icon(Icons.trending_up),
                title: Text(test), // ERROR: error: Evaluation of this constant expression throws an exception.
                subtitle: Text('Apple Incorporated'),
              ),
            ],
          ),
        ),
      )
    );
  }

}

How would I achieve this and why does flutter not allow this to happen?

Answer 1

This happens because you try to instantiate the parent ListTile as const.

But for ListTile to be const, it requires its child Text to be const too, therefore cannot have a variable. Just change ListTile to not be const:

ListTile(
   ...
)