onChangeStart property
Signature for a callback that reports the value of a marker pointer has started to change.
This snippet shows how to call onChangeStart function in SfLinearGauge.
SfLinearGauge(
markerPointers: [
LinearWidgetPointer(
value: _pointerValue,
child: Container(
height: 20,
width: 20,
color: Colors.red),
onChangeStart: (double startValue) {
print('Start value $startValue');
},
)])
Implementation
@override
final ValueChanged<double>? onChangeStart;