TouchedSpotIndicatorData constructor
if LineTouchData.handleBuiltInTouches is true, LineChart shows a thicker line and larger spot as indicator automatically when touch happens, otherwise you can show it manually using LineChartBarData.showingIndicators. indicatorBelowLine determines line's style, and touchedSpotDotData determines dot's style.
Implementation
const TouchedSpotIndicatorData(
this.indicatorBelowLine,
this.touchedSpotDotData,
);