개요
======== Exception caught by widgets library =======================================================
The following assertion was thrown while applying parent data.:
Incorrect use of ParentDataWidget.
The ParentDataWidget Expanded(flex: 1) wants to apply ParentData of type FlexParentData to a RenderObject, which has been set up to accept ParentData of incompatible type ParentData.
Usually, this means that the Expanded widget has the wrong ancestor RenderObjectWidget. Typically, Expanded widgets are placed directly inside Flex widgets.
The offending Expanded is currently placed inside a ConstrainedBox widget.
해결
Expanded 의 부모 위젯을 Colunm Row Flex가 아닌 이외의 위젯, 예를 들어 ConstraintBox 위젯으로 설정했을 경우 발생합니다.
참고 자료