ExpansionPanel constructor

ExpansionPanel({@required ExpansionPanelHeaderBuilder headerBuilder, @required Widget body, bool isExpanded: false })

Creates an expansion panel to be used as a child for ExpansionPanelList.

The headerBuilder, body, and isExpanded arguments must not be null.

Implementation 

ExpansionPanel({
  @required this.headerBuilder,
  @required this.body,
  this.isExpanded = false
}) : assert(headerBuilder != null),
     assert(body != null),
     assert(isExpanded != null);