'This expression has a type of 'void' so its value can't be used.' setState() error in Flutter

Question

I am getting the error quoted above when I try to rebuild a class. The class I am calling, ListOfIngs(), is a class that basically creates a textField, but my goal is to create a large amount of TextFields, the variable countIngs holds the value for the exact number, in a listView. Here is the code:

        body: Container(
      padding: EdgeInsets.fromLTRB(10.0, 20.0, 10.0, 30.0),
      child: Column(
        children: <Widget>[
          Row(
            children: <Widget>[
              Text('Ingredients',
                  style: GoogleFonts.biryani(fontSize: 15.0)),
              IconButton(
                icon: new Icon(Icons.add),
                onPressed: () {
                  setState(() {
                    countings++;
                  });
                  debugPrint('$countings');
                },
              )
            ],
          ),
          setState(() {
            ListOfIngsWidget(countings);
          }),
        ],
      ),
    )

Answer 1

Try this:

class ListOfIngs extends State<ListOfIngsWidget> {
  final int countIngs;
  final myController = new TextEditingController();
  ListOfIngs(
    this.countIngs,
  );
  Widget build(BuildContext contex) {
    return new Container(
        child: ListView.builder(
            itemCount: countIngs,
            itemBuilder: (context,index){
              return Container(
                child: TextField(
                  controller: myController,
                  decoration: InputDecoration(
                    border: OutlineInputBorder(),
                    labelText: 'Ingredient $index',
                  ),
                ),
              );
            },
          ),
       );
  }
}