My ElevatedButton widgets do not update the variable they are supposed to for the rest of the program

Question

`import 'package:flutter/material.dart';

class SkillEntry extends StatefulWidget {
   const SkillEntry({super.key, required this.skll});

   final String skll;

  @override
  State<SkillEntry> createState() => _SkillEntryState();
}

class _SkillEntryState extends State<SkillEntry> {


  @override
  Widget build(BuildContext context) {

     int skillvalue = 0;

    return Container(
        height: 40,
        width: 200,
        child: Row(children: [
          const Flexible(flex: 20, child:
          TextField(decoration:(
              InputDecoration(
                  border: OutlineInputBorder(),
                  hintText: ('Name and Skill'))),)),
          ElevatedButton(onPressed: PlusOne(skillvalue), child: Icon(Icons.add_circle)),
          ElevatedButton(onPressed: MinusOne(skillvalue), child: Icon(Icons.exposure_minus_1)),
          Flexible(flex: 7, child:
           Text('$skillvalue',)),
        ]));
  }
  PlusOne(skillvalue) {
    setState(() {
      skillvalue = skillvalue + 1;
      return skillvalue;
      });
  }

  MinusOne(skillvalue) {
    setState(() {
      skillvalue = skillvalue - 1;
      return skillvalue;
    });
  }
}

As it stands currently the buttons seemingly do nothing. I suspect that I'm getting the skillvalue variable into the function PlusOne but not properly returning it to the main program, or I might not be using setstate correctly. How can I solve this?

Answer 1

first of all, skillValue is declared in build method, the value will always be zero.

secondly, the way you use ElevatedButton is wrong, you can not use a void method return value as a parameter to onPressed, which means the onPressed always be null.

here is my demo code.

class SkillEntry extends StatefulWidget {
  const SkillEntry({super.key, required this.skll});

  final String skll;

  @override
  State<SkillEntry> createState() => _SkillEntryState();
}

class _SkillEntryState extends State<SkillEntry> {

  int skillvalue = 0;
  @override
  Widget build(BuildContext context) {



    return Container(
        height: 40,
        width: 200,
        child: Row(children: [
          const Flexible(flex: 20, child:
          TextField(decoration:(
              InputDecoration(
                  border: OutlineInputBorder(),
                  hintText: ('Name and Skill'))),)),
          ElevatedButton(onPressed: PlusOne, child: Icon(Icons.add_circle)),
          ElevatedButton(onPressed: MinusOne, child: Icon(Icons.exposure_minus_1)),
          Flexible(flex: 7, child:
          Text('$skillvalue',)),
        ]));
  }
  PlusOne() {
    setState(() {
      skillvalue = skillvalue + 1;
    });
  }

  MinusOne() {
    setState(() {
      skillvalue = skillvalue - 1;
    });
  }
}