I have a Flutter stateful widget inside a

The first step of the stepper widget has another widget as its content, and that widget is a stateful widget as below:

import 'package:flutter/material.dart';

class ConductorStart extends StatefulWidget {
  const ConductorStart({
    Key? key,
    required this.continued,
  }) : super(key: key);

  final VoidCallback continued;

  @override
  ConductorStartState createState() => ConductorStartState();
}

class ConductorStartState extends State<ConductorStart> {
  int _currentStep = 0;
  bool _pressedButton = false;

  void tapped() {
    setState(() => _pressedButton = true);
  }

  @override
  Widget build(BuildContext context) {
    return Row(
      children: <Widget>[
        if (!_pressedButton)
          ElevatedButton(
            onPressed: () {
              tapped;
              widget.continued;
            },
            child: const Text('Continue'),
          )
        else
          const SizedBox.shrink(),
      ],
    );
  }
}

The ElevatedButton has two functions when called: tapped, and widget.continued. tapped should make the button disappear. and widget.continued is a function from the parent widget that is supposed to make the parent widget to continue to step 2 when clicked. Currently the two functions have a warning of Avoid using unnecessary statements, and they do not get executed properly. When I click the continue button. Nothing happens. What did I do wrong here?

CodePudding user response：

I'll totally go with Pat9RB. Just posting it here as an answer for others to quickly find the relevant issue.

Adding just definitions helps for adding a callback parameter in the constructor. For Eg.: onPressed: myOnPressed; where, onPressed needs a VoidCallback, and myOnPressed is a VoidCallback argument.

But, you need to call the function in order to execute it from any other function body. Either call using .call() method, like, tapped!.call(); or append with callback syntax (), like, tapped();