CODEWITHSUNDEEP
flutter
Hsu Mark
Hsu Mark

Reputation: 71

Why can't I use flutter stepper's controlsBuilder

I can execute the sample code in demo project, but when I past the code to my project it shows:

The argument type 'Row Function(BuildContext, {void Function() onStepCancel, void Function() onStepContinue})' can't be assigned to the parameter type 'Widget Function(BuildContext, {void Function()? onStepCancel, void Function()? onStepContinue})?

if I remove the controlsBuilder:..., the code works normally, thanks.

import 'package:flutter/material.dart';

class StepperDemo extends StatefulWidget {
  @override
  _StepperDemoState createState() => _StepperDemoState();
}

class _StepperDemoState extends State<StepperDemo> {
  int _currentStep = 0;
  StepperType stepperType = StepperType.vertical;

  @override
  Widget build(BuildContext context) {
    return  Scaffold(
      appBar: AppBar(
        automaticallyImplyLeading: false,
        title: Text('Flutter Stepper Demo'),
        centerTitle: true,
      ),
      body:  Container(
        child: Column(
          children: [
            Expanded(
              child: Stepper(

                controlsBuilder: (BuildContext context, {VoidCallback onStepContinue, VoidCallback onStepCancel}) {
                  return Row(
                    children: <Widget>[
                      TextButton(
                        onPressed: onStepContinue,
                        child: const Text('下一步'),
                      ),
                      TextButton(
                        onPressed: onStepCancel,
                        child: const Text('離開'),
                      ),
                    ],
                  );
                },

Upvotes: 6

Views: 5188

Answers (2)

Kipruto
Kipruto

Reputation: 857

New documentation suggests that you do use ControlDetails details

 controlsBuilder: (BuildContext context, ControlsDetails details){}

Upvotes: 0

ckyony
ckyony

Reputation: 261

Prior to Flutter 2.6.0, the controlsBuilder returns two callbacks: onStepContinue and onStepCancel. These callbacks are now replaced with a single ControlsDetails object.

You can rewrite your Stepper constructor as follow

             child: Stepper(

                controlsBuilder: (BuildContext context, ControlsDetails controls) {
                  return Row(
                    children: <Widget>[
                      TextButton(
                        onPressed: controls.onStepContinue,
                        child: const Text('下一步'),
                      ),
                      TextButton(
                        onPressed: controls.onStepCancel,
                        child: const Text('離開'),
                      ),
                    ],
                  );
                },

Upvotes: 24

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