A convenience widget that combines common painting, positioning, and sizing widgets.

A container first surrounds the child with padding (inflated by any borders present in the decoration) and then applies additional constraints to the padded extent (incorporating the width and height as constraints, if either is non-null). The container is then surrounded by additional empty space described from the margin.

During painting, the container first applies the given transform, then paints the decoration to fill the padded extent, then it paints the child, and finally paints the foregroundDecoration, also filling the padded extent.

Containers with no children try to be as big as possible unless the incoming constraints are unbounded, in which case they try to be as small as possible. Containers with children size themselves to their children. The width, height, and constraints arguments to the constructor override this.



Container({Key key, FractionalOffset alignment, EdgeInsets padding, Color color, Decoration decoration, Decoration foregroundDecoration, double width, double height, BoxConstraints constraints, EdgeInsets margin, Matrix4 transform, Widget child })

Creates a widget that combines common painting, positioning, and sizing widgets.


alignment FractionalOffset

Align the child within the container.

child Widget

The child contained by the container.

constraints BoxConstraints

Additional constraints to apply to the child.

decoration Decoration

The decoration to paint behind the child.

foregroundDecoration Decoration

The decoration to paint in front of the child.

margin EdgeInsets

Empty space to surround the decoration and child.

padding EdgeInsets

Empty space to inscribe inside the decoration. The child, if any, is placed inside this padding.

transform Matrix4

The transformation matrix to apply before painting the container.

hashCode int

The hash code for this object.

read-only, inherited
key Key

Controls how one widget replaces another widget in the tree.

final, inherited
runtimeType Type

A representation of the runtime type of the object.

read-only, inherited


operator ==(other) bool

The equality operator.



build(BuildContext context) Widget

Describes the part of the user interface represented by this widget.

debugFillDescription(List<String> description) → void

Add additional information to the given description for use by toString.

createElement() StatelessElement

Creates a StatelessElement to manage this widget's location in the tree.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a non-existent method or property is accessed.

toString() String

Returns a string representation of this object.

toStringShort() String

A short, textual description of this widget.