A widget that controls where a child of a Stack is positioned.
A Positioned widget must be a descendant of a Stack, and the path from the Positioned widget to its enclosing Stack must contain only StatelessWidgets or StatefulWidgets (not other kinds of widgets, like RenderObjectWidgets).
If a widget is wrapped in a Positioned, then it is a positioned widget in its Stack. If the top property is non-null, the top edge of this child will be positioned top layout units from the top of the stack widget. The right, bottom, and left properties work analogously.
If both the top and bottom properties are non-null, then the child will be forced to have exactly the height required to satisfy both constraints. Similarly, setting the right and left properties to non-null values will force the child to have a particular width. Alternatively the width and height properties can be used to give the dimensions, with one corresponding position property (e.g. top and height).
- Inheritance
- Object
- Widget
- ProxyWidget
- ParentDataWidget<Stack>
- Positioned
Constructors
- Positioned({Key key, double left, double top, double right, double bottom, double width, double height, @required Widget child })
-
Creates a widget that controls where a child of a Stack is positioned.
- Positioned.fill({Key key, Widget child, double left: 0.0, double top: 0.0, double right: 0.0, double bottom: 0.0 })
-
Creates a Positioned object with left, top, right, and bottom set to 0.0 unless a value for them is passed.
- Positioned.fromRect({Key key, Widget child, Rect rect })
-
Creates a Positioned object with the values from the given Rect.
Properties
- bottom → double
-
The distance that the child's bottom edge is inset from the bottom of the stack.
read-only - height → double
-
The child's height.
read-only - left → double
-
The distance that the child's left edge is inset from the left of the stack.
read-only - right → double
-
The distance that the child's right edge is inset from the right of the stack.
read-only - top → double
-
The distance that the child's top edge is inset from the top of the stack.
read-only - width → double
-
The child's width.
read-only - child → Widget
-
The widget below this widget in the tree.
read-only, 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.
read-only, inherited - runtimeType → Type
-
A representation of the runtime type of the object.
read-only, inherited
Operators
-
operator ==(
other) → bool -
The equality operator.
inherited
Methods
-
applyParentData(
RenderObject renderObject) → void -
Write the data from this widget into the given render object's parent data.
-
debugFillDescription(
List<String> description) → void -
Add additional information to the given description for use by
toString. -
createElement(
) → ParentDataElement<Stack> -
Inflates this configuration to a concrete instance.
inherited -
debugDescribeInvalidAncestorChain(
{String description, String ownershipChain, bool foundValidAncestor, Iterable<Widget> badAncestors }) → String -
Subclasses should override this to describe the requirements for using the ParentDataWidget subclass. It is called when debugIsValidAncestor() returned false for an ancestor, or when there are extraneous ParentDataWidgets in the ancestor chain.
inherited -
debugIsValidAncestor(
RenderObjectWidget ancestor) → bool -
Subclasses should override this method to return true if the given ancestor is a RenderObjectWidget that wraps a RenderObject that can handle the kind of ParentData widget that the ParentDataWidget subclass handles.
inherited -
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a non-existent method or property is accessed.
inherited -
toString(
) → String -
Returns a string representation of this object.
inherited -
toStringShort(
) → String -
A short, textual description of this widget.
inherited