title: 'This expression has a type of 'void' so its value can't be used.' setState() error in Flutter
body: <p>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:</p>
  <pre><code>        body: Container(
        padding: EdgeInsets.fromLTRB(10.0, 20.0, 10.0, 30.0),
        child: Column(
          children: &lt;Widget&gt;[
            Row(
              children: &lt;Widget&gt;[
                Text('Ingredients',
                    style: GoogleFonts.biryani(fontSize: 15.0)),
                IconButton(
                  icon: new Icon(Icons.add),
                  onPressed: () {
                    setState(() {
                      countings++;
                    });
                    debugPrint('$countings');
                  },
                )
              ],
            ),
            setState(() {
              ListOfIngsWidget(countings);
            }),
          ],
        ),
      )
  </code></pre>