build method Null safety Describes the part of the user interface represented by this widget . The framework calls this method when this widget is inserted into the tree in a given BuildContext and when the dependencies of this widget change (e.g., an InheritedWidget referenced by this widget changes).
What is build in Flutter?
Flutter widgets are built using a modern framework that takes inspiration from React . The central idea is that you build your UI out of widgets. Widgets describe what their view should look like given their current configuration and state.