onChangeStart property
Called when the user starts selecting a new value for the slider.
This callback shouldn't be used to update the slider value
(use
onChanged for that), but rather to be notified when the user has started
selecting a new value by starting a drag or with a tap.
The value passed will be the last value
that the slider had before the
change began.
See also:
- onChangeEnd for a callback that is called when the value change is complete.
Implementation
final ValueChanged<double>? onChangeStart;