Padding class Null safety

A widget that insets its child by the given padding.

When passing layout constraints to its child, padding shrinks the constraints by the given padding, causing the child to layout at a smaller size. Padding then sizes itself to its child's size, inflated by the padding, effectively creating empty space around the child.

This snippet creates "Hello World!" Text inside a Card that is indented by sixteen pixels in each direction.

const Card(
  child: Padding(
    padding: EdgeInsets.all(16.0),
    child: Text('Hello World!'),
  ),
)

Design discussion

There isn't really any difference between the two. If you supply a Container.padding argument, Container simply builds a Padding widget for you.

Container doesn't implement its properties directly. Instead, Container combines a number of simpler widgets together into a convenient package. For example, the Container.padding property causes the container to build a Padding widget and the Container.decoration property causes the container to build a DecoratedBox widget. If you find Container convenient, feel free to use it. If not, feel free to build these simpler widgets in whatever combination meets your needs.

In fact, the majority of widgets in Flutter are simply combinations of other simpler widgets. Composition, rather than inheritance, is the primary mechanism for building up widgets.

Constructors

Padding({Key? key, required EdgeInsetsGeometry padding, Widget? child}): Creates a widget that insets its child.
const

Properties

child → Widget?: The widget below this widget in the tree.
finalinherited
hashCode → int: The hash code for this object.
nonVirtual">@nonVirtualread-onlyinherited
key → Key?: Controls how one widget replaces another widget in the tree.
finalinherited
padding → EdgeInsetsGeometry: The amount of space by which to inset the child.
final
runtimeType → Type: A representation of the runtime type of the object.
read-onlyinherited

Methods

createElement() → SingleChildRenderObjectElement: RenderObjectWidgets always inflate to a RenderObjectElement subclass.
inherited
createRenderObject(BuildContext context) → RenderPadding: Creates an instance of the RenderObject class that this RenderObjectWidget represents, using the configuration described by this RenderObjectWidget.
override
debugDescribeChildren() → List<DiagnosticsNode>: Returns a list of DiagnosticsNode objects describing this node's children.
protected">@protectedinherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void: Add additional properties associated with the node.
override
didUnmountRenderObject(covariant RenderObject renderObject) → void: A render object previously associated with this widget has been removed from the tree. The given RenderObject will be of the same type as returned by this object's createRenderObject.
protected">@protectedinherited
noSuchMethod(Invocation invocation) → dynamic: Invoked when a non-existent method or property is accessed.
inherited
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode: Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
inherited
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String: A string representation of this object.
inherited
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String: Returns a string representation of this node and its descendants.
inherited
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String: Returns a one-line detailed description of the object.
inherited
toStringShort() → String: A short, textual description of this widget.
inherited
updateRenderObject(BuildContext context, covariant RenderPadding renderObject) → void: Copies the configuration described by this RenderObjectWidget to the given RenderObject, which will be of the same type as returned by this object's createRenderObject.
override

Operators

operator ==(Object other) → bool: The equality operator.
nonVirtual">@nonVirtualinherited

Flutter
widgets
Padding class