InputBorder constructor
Creates a border for an InputDecorator.
The borderSide
parameter must not be null. Applications typically do
not specify a borderSide
parameter because the input decorator
substitutes its own, using copyWith, based on the current theme and
InputDecorator.isFocused.
Implementation
const InputBorder({
this.borderSide = BorderSide.none,
}) : assert(borderSide != null);