Border class Null safety

A border of a box, comprised of four sides: top, right, bottom, left.

The sides are represented by BorderSide objects.

link
All four borders the same, two-pixel wide solid white: 
Border.all(width: 2.0, color: const Color(0xFFFFFFFF))

link
The border for a Material Design divider: 
Border(bottom: BorderSide(color: Theme.of(context).dividerColor))

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A 1990s-era "OK" button: 
Container(
  decoration: const BoxDecoration(
    border: Border(
      top: BorderSide(color: Color(0xFFFFFFFF)),
      left: BorderSide(color: Color(0xFFFFFFFF)),
      right: BorderSide(),
      bottom: BorderSide(),
    ),
  ),
  child: Container(
    padding: const EdgeInsets.symmetric(horizontal: 20.0, vertical: 2.0),
    decoration: const BoxDecoration(
      border: Border(
        top: BorderSide(color: Color(0xFFDFDFDF)),
        left: BorderSide(color: Color(0xFFDFDFDF)),
        right: BorderSide(color: Color(0xFF7F7F7F)),
        bottom: BorderSide(color: Color(0xFF7F7F7F)),
      ),
      color: Color(0xFFBFBFBF),
    ),
    child: const Text(
      'OK',
      textAlign: TextAlign.center,
      style: TextStyle(color: Color(0xFF000000))
    ),
  ),
)

See also:

  • BoxDecoration, which uses this class to describe its edge decoration.
  • BorderSide, which is used to describe each side of the box.
  • Theme, from the material layer, which can be queried to obtain appropriate colors to use for borders in a MaterialApp, as shown in the "divider" sample above.
Inheritance

Constructors

Border({BorderSide top = BorderSide.none, BorderSide right = BorderSide.none, BorderSide bottom = BorderSide.none, BorderSide left = BorderSide.none})
Creates a border.
const
Border.all({Color color = const Color(0xFF000000), double width = 1.0, BorderStyle style = BorderStyle.solid, StrokeAlign strokeAlign = StrokeAlign.inside})
A uniform border with all sides the same color and width.
factory
Border.fromBorderSide(BorderSide side)
Creates a border whose sides are all the same.
const
Border.symmetric({BorderSide vertical = BorderSide.none, BorderSide horizontal = BorderSide.none})
Creates a border with symmetrical vertical and horizontal sides.
const

Properties

bottom → BorderSide
The bottom side of this border.
final
dimensions → EdgeInsetsGeometry
The widths of the sides of this border represented as an EdgeInsets.
read-onlyoverride
hashCode → int
The hash code for this object.
read-onlyoverride
isUniform → bool
Whether all four sides of the border are identical. Uniform borders are typically more efficient to paint.
read-onlyoverride
left → BorderSide
The left side of this border.
final
The right side of this border.
final
runtimeType → Type
A representation of the runtime type of the object.
read-onlyinherited
top → BorderSide
The top side of this border.
final

Methods

add(ShapeBorder other, {bool reversed = false}) → Border?
Attempts to create a new object that represents the amalgamation of this border and the other border.
override
getInnerPath(Rect rect, {TextDirection? textDirection}) → Path
Create a Path that describes the inner edge of the border.
inherited
getOuterPath(Rect rect, {TextDirection? textDirection}) → Path
Create a Path that describes the outer edge of the border.
inherited
lerpFrom(ShapeBorder? a, double t) → ShapeBorder?
Linearly interpolates from another ShapeBorder (possibly of another class) to this.
override
lerpTo(ShapeBorder? b, double t) → ShapeBorder?
Linearly interpolates from this to another ShapeBorder (possibly of another class).
override
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
inherited
paint(Canvas canvas, Rect rect, {TextDirection? textDirection, BoxShape shape = BoxShape.rectangle, BorderRadius? borderRadius}) → void
Paints the border within the given Rect on the given Canvas.
override
scale(double t) → Border
Creates a copy of this border, scaled by the factor t.
override
toString() → String
A string representation of this object.
override

Operators

operator +(ShapeBorder other) → ShapeBorder
Creates a new border consisting of the two borders on either side of the operator.
inherited
operator ==(Object other) → bool
The equality operator.
override

Static Methods

lerp(Border? a, Border? b, double t) → Border?
Linearly interpolate between two borders.
override
merge(Border a, Border b) → Border
Creates a Border that represents the addition of the two given Borders.