expansionIndicator property
expansionIndicator can be customized to provide any expansion widget
and collapse widget. The pre-built available expansionIndicators are
** ExpansionIndicator.RightUpChevron
** ExpansionIndicator.PlusMinus
** ExpansionIndicator.DownUpChevron
You can simply pass null, if you do not want to show an expansionIndicator
Implementation
final ExpansionIndicator? expansionIndicator;