I want to use a ListWheelScrollView in Flutter but only output the Selected Item after its Selected

Question

I want to use a ListWheelScrollView in Flutter but only output the Selected Item after its Selected. So beacause now when i go from the bottom to the Top in one Go it outputs every item...

This is my Code:

List<int> numbers = List.generate(3, (index) => index + 1);

void _updateSelectedCardType(int index) {
  setState(() {
    _selectedIndex = index;
    switch (index) {
      case 0:
        selectedCard = '1';
        break;
      case 1:
        selectedCard = '2';
        break;
      case 2:
        selectedCard = '3';
        break;
    }
  sleep(const Duration(seconds: 1));
  print('Selected card type: $selectedCard');
}

Here I tried to only output it after a second so if its selected and doesnt change I can print it... any idea on how to do it

Answer 1

try that

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

class MyWidget extends StatefulWidget {
  @override
  _MyWidgetState createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  int _selectedIndex = 0;
  String selectedCard = '1';
  Timer? _timer;

  List<int> numbers = List.generate(3, (index) => index + 1);

  @override
  void dispose() {
    _timer?.cancel();
    super.dispose();
  }

  void _onSelectedItemChanged(int index) {
    setState(() {
      _selectedIndex = index;
      switch (index) {
        case 0:
          selectedCard = '1';
          break;
        case 1:
          selectedCard = '2';
          break;
        case 2:
          selectedCard = '3';
          break;
      }
    });
    _timer?.cancel();
    _timer = Timer(Duration(milliseconds: 500), () {
      print('Selected card type: $selectedCard');
    });
  }

  @override
  Widget build(BuildContext context) {
    return ListWheelScrollView(
      itemExtent: 50,
      children: numbers.map((number) {
        return Center(child: Text('$number'));
      }).toList(),
      onSelectedItemChanged: _onSelectedItemChanged,
      physics: FixedExtentScrollPhysics(),
    );
  }
}