createState method
Creates the mutable state for this component at a given location in the tree.
Subclasses should override this method to return a newly created
instance of their associated State subclass:
@override
State<MyComponent> createState() => _MyComponentState();
The framework can call this method multiple times over the lifetime of
a StatefulComponent. For example, if the component is inserted into the tree
in multiple locations, the framework will create a separate State object
for each location. Similarly, if the component is removed from the tree and
later inserted into the tree again, the framework will call createState
again to create a fresh State object, simplifying the lifecycle of
State objects.
Implementation
@override
_Selector0State<T> createState() => _Selector0State<T>();