activeTrackHeight property Null safety

double activeTrackHeight

Specifies the height for the active track in the SfSlider, SfRangeSlider, and SfRangeSelector.

Defaults to 2.0.

This snippet shows how to set active track height in SfRangeSliderThemeData.

SfRangeValues _values = SfRangeValues(4.0, 7.0);

  body: Center(
      child: SfRangeSliderTheme(
          data: SfRangeSliderThemeData(
              activeTrackHeight: 8,
          child:  SfRangeSlider(
              min: 2.0,
              max: 10.0,
              values: _values,
              onChanged: (SfRangeValues newValues){
                  setState(() {
                      _values = newValues;


final double activeTrackHeight;