onChangeStart property Null safety

ValueChanged<RangeValues>? onChangeStart
final

Called when the user starts selecting new values for the slider.

This callback shouldn't be used to update the slider values (use onChanged for that). Rather, it should be used to be notified when the user has started selecting a new value by starting a drag or with a tap.

The values passed will be the last values that the slider had before the change began.

link 
RangeSlider(
  values: _rangeValues,
  min: 1.0,
  max: 10.0,
  onChanged: (RangeValues newValues) {
    setState(() {
      _rangeValues = newValues;
    });
  },
  onChangeStart: (RangeValues startValues) {
    print('Started change at $startValues');
  },
)

See also:

  • onChangeEnd for a callback that is called when the value change is complete.

Implementation

final ValueChanged<RangeValues>? onChangeStart;