content: import 'package:flutter/material.dart';
  
  class SliderPreview extends StatelessWidget {
    final ThemeData theme;
  
    const SliderPreview({Key key, this.theme}) : super(key: key);
  
    @override
    Widget build(BuildContext context) {
      return Padding(
        padding: EdgeInsets.all(8.0),
        child: Column(
          mainAxisSize: MainAxisSize.max,
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
          children: [
            _FakeSlider(divisions: 10),
            _FakeSlider(
              divisions: null,
              labelPrefix: '',
            ),
            _FakeSlider(disabled: true),
          ],
        ),
      );
    }
  }
  
  class _FakeSlider extends StatefulWidget {
    final bool disabled;
    final int divisions;
    final int id;
    final String labelPrefix;
  
    _FakeSlider(
        {this.id,
        this.disabled: false,
        this.divisions: 10,
        this.labelPrefix: 'Value'});
  
    @override
    _FakeSliderState createState() => _FakeSliderState();
  }
  
  class _FakeSliderState extends State<_FakeSlider> {
    double value = 0.5;
  
    _FakeSliderState();
  
    @override
    Widget build(BuildContext context) {
      print('_FakeSliderState.build... ');
      return Padding(
        padding: const EdgeInsets.all(8.0),
        child: Slider(
            key: Key(widget.id.toString()),
            divisions: widget.divisions,
            value: value,
            /*label: '${widget.labelPrefix}' */ /* ${value.toStringAsFixed(2)} */ /*,*/
            onChanged: widget.disabled
                ? null
                : (newValue) => setState(() => value = newValue)),
      );
    }
  }
  