createState method
Creates the mutable state for this widget 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<SomeWidget> createState() => _SomeWidgetState();
The framework can call this method multiple times over the lifetime of a StatefulWidget. For example, if the widget is inserted into the tree in multiple locations, the framework will create a separate State object for each location. Similarly, if the widget 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
_KKiaPayState createState() => _KKiaPayState(
this.amount ,
this.phone,
this.partnerId,
this.countries,
this.reason,
this.data,
this.paymentMethods,
this.sandbox,
this.apikey,
this.callback,
this.theme,
this.name,
this.email,
);