What is widget class flutter?

ValueChanged<T> = void Function(T value) Signature for callbacks that report that an underlying value has changed . See also: ValueSetter, for callbacks that report that a value has been set.

Widget class Null safety Widgets are the central class hierarchy in the Flutter framework . A widget is an immutable description of part of a user interface. Widgets can be inflated into elements, which manage the underlying render tree. Widgets themselves have no mutable state (all their fields must be final).

ValueChanged<T> = void Function(T value) Signature for callbacks that report that an underlying value has changed . See also: ValueSetter, for callbacks that report that a value has been set.