todos-contra-el-fuego-mobile/lib/slider.dart

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

import 'colors.dart';
import 'generated/i18n.dart';

typedef SlideCallback = void Function(int distance);

class FireDistanceSlider extends StatefulWidget {

  const FireDistanceSlider({super.key, required this.initialValue, required this.onSlide});
  final int initialValue;
  final SlideCallback onSlide;

  @override
  _FireDistanceSliderState createState() => _FireDistanceSliderState(
      initialValue: initialValue, onSlide: onSlide);
}

class _FireDistanceSliderState extends State<FireDistanceSlider> {

  _FireDistanceSliderState({int initialValue = 10, required this.onSlide}) {
    _sliderValue = initialValue;
  }
  late int _sliderValue;
  final SlideCallback onSlide;

  Widget sizeText(int sliderValue) => Text(
      S.of(context).subscribeToValueAroundThisArea(sliderValue.toString()),
      style: const TextStyle(color: Colors.black87));

  Widget warningText(int sliderValue) => _sliderValue >= 50
      ? Text(S.of(context).warningThisIsAVeryLargeArea,
          style: const TextStyle(color: fires900))
      : const Text('');

  @override
  Widget build(BuildContext context) {
    final Slider slider = Slider(
      value: _sliderValue + 0.0,
      activeColor: fires900,
      inactiveColor: Colors.black45,
      min: 1.0,
      max: 100.0,
      divisions: 99,
      label: '$_sliderValue',
      onChanged: (double value) {
        _sliderValue = value.round();
        onSlide(_sliderValue);
        setState(() {});
      },
    );
    return Column(
      mainAxisSize: MainAxisSize.min,
      children: listWithoutNulls(<Widget>[
        const SizedBox(height: 50.0),
        Row(children: <Widget>[slider]),
        // new SizedBox(height: 5.0),
        Column(children: <Widget>[
          sizeText(_sliderValue),
          const SizedBox(height: 5.0),
          warningText(_sliderValue)
        ])
      ]),
    );
  }
}