A widget that uses the stack layout algorithm for its children.
This class is useful if you want to overlap several children in a simple way, for example having some text and an image, overlaid with a gradient and a button attached to the bottom.
Each child of a Stack widget is either positioned or non-positioned. Positioned children are those wrapped in a Positioned widget that has at least one non-null property. The stack sizes itself to contain all the non-positioned children, which are positioned according to alignment (which defaults to the top-left corner). The positioned children are then placed relative to the stack according to their top, right, bottom, and left properties.
The stack paints its children in order. If you want to change the order in which the children paint, you can rebuild the stack with the children in the new order. If you reorder the children in this way, consider giving the children non-null keys. These keys will cause the framework to move the underlying objects for the children to their new locations rather than recreate them at their new location.
For more details about the stack layout algorithm, see RenderStack.
If you want to lay a number of children out in a particular pattern, or if you want to make a custom layout manager, you probably want to use CustomMultiChildLayout instead. In particular, when using a Stack you can't position children relative to their size or the stack's own size.
- Align, which sizes itself based on its child's size and positions the child according to a FractionalOffset value.
- CustomSingleChildLayout, which uses a delegate to control the layout of a single child.
- CustomMultiChildLayout, which uses a delegate to position multiple children.
- Flow, which provides paint-time control of its children using transform matrices.
- alignment → FractionalOffset
How to align the non-positioned children in the stack.final
- overflow → Overflow
Whether overflowing children should be clipped. See Overflow.final
- children → List<Widget>
The widgets below this widget in the tree.final, inherited
- hashCode → int
Get a 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
BuildContext context) → RenderStack
Creates an instance of the
RenderObjectclass that this
RenderObjectWidgetrepresents, using the configuration described by this
BuildContext context, RenderStack renderObject) → void
Copies the configuration described by this
RenderObjectWidgetto the given
RenderObject, which will be of the same type as returned by this object's
) → MultiChildRenderObjectElement
RenderObjectWidgets always inflate to a
List<String> description) → void
Add additional information to the given description for use by toString.mustCallSuper, protected, inherited
RenderObject, renderObject) → void
A render object previously associated with this widget has been removed from the tree. The given
RenderObjectwill be of the same type as returned by this object's createRenderObject.protected, inherited
Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.inherited
) → String
Returns a string representation of this object.inherited
) → String
A short, textual description of this widget.inherited