Interview frequency: …
Short answer
BuildContext is a handle to a widget's position inside the element tree, and through it you look up ancestors such as Theme or an InheritedWidget.
Explanation
The context determines the scope in which APIs such as Theme.of and MediaQuery.of search. Do not keep it after dispose, and do not use a context that is above the Provider or Navigator you want to reach.
Common mistakes
- Using a parent's context to reach a widget below it.
- Storing a BuildContext to use after its lifecycle ends.