MaterialStateBorderSide class Null safety

Defines a BorderSide whose value depends on a set of MaterialStates which represent the interactive state of a component.

To use a MaterialStateBorderSide, you should create a subclass of a MaterialStateBorderSide and override the abstract resolve method.

This example defines a subclass of MaterialStateBorderSide, that resolves to a red border side when its widget is selected.

To create a local project with this code sample, run:
flutter create --sample=material.MaterialStateBorderSide.1 mysample

This example defines a subclass of MaterialStateBorderSide, that resolves to a red border side when its widget is selected.

class RedSelectedBorderSide extends MaterialStateBorderSide {
  @override
  BorderSide? resolve(Set<MaterialState> states) {
    if (states.contains(MaterialState.selected)) {
      return BorderSide(
        width: 1,
        color: Colors.red,
      );
    }
    return null;  // Defer to default value on the theme or widget.
  }
}

// ...

bool isSelected = true;

Widget build(BuildContext context) {
  return FilterChip(
    label: Text('Select chip'),
    selected: isSelected,
    onSelected: (bool value) {
      setState(() {
        isSelected = value;
      });
    },
    side: RedSelectedBorderSide(),
  );
}

This class should only be used for parameters which are documented to take MaterialStateBorderSide, otherwise only the default state will be used.

Inheritance

Object
BorderSide
MaterialStateBorderSide

Implemented types

MaterialStateProperty<BorderSide?>

Constructors

MaterialStateBorderSide(): Creates a MaterialStateBorderSide.
const

Properties

color → Color: The color of this side of the border.
final, inherited
hashCode → int: The hash code for this object. [...]
read-only, inherited
runtimeType → Type: A representation of the runtime type of the object.
read-only, inherited
style → BorderStyle: The style of this side of the border. [...]
final, inherited
width → double: The width of this side of the border, in logical pixels. [...]
final, inherited

Methods

copyWith({Color? color, double? width, BorderStyle? style}) → BorderSide: Creates a copy of this border but with the given fields replaced with the new values.
inherited
noSuchMethod(Invocation invocation) → dynamic: Invoked when a non-existent method or property is accessed. [...]
inherited
resolve(Set<MaterialState> states) → BorderSide?: Returns a BorderSide that's to be used when a Material component is in the specified state. Return null to defer to the default value of the widget or theme.
override
scale(double t) → BorderSide: Creates a copy of this border side description but with the width scaled by the factor t. [...]
inherited
toPaint() → Paint: Create a Paint object that, if used to stroke a line, will draw the line in this border's style. [...]
inherited
toString() → String: A string representation of this object. [...]
inherited

Operators

operator ==(Object other) → bool: The equality operator. [...]
inherited