RenderPositionedBox class
A render object that positions its child within the available space according to an alignment.
This is the render object used by Align widgets to position their children without relying on Container widgets, avoiding circular dependencies.
- Inheritance
-
- Object
- RenderObject
- RenderBox
- RenderPositionedBox
- Mixed-in types
Constructors
- RenderPositionedBox({required Alignment alignment, RenderBox? child})
-
Stores the alignment and adopts
childwhen given.
Properties
- alignment ↔ Alignment
-
Placement of the child within the leftover space, from (-1, -1)
top-left through (0, 0) center to (1, 1) bottom-right.
getter/setter pair
- child → RenderBox?
-
The single direct render child, or
nullwhen there is none.no setteroverride -
children
→ List<
RenderObject> -
Live read-only view of direct children in traversal order.
latefinalinherited
- debugNeedsLayout → bool
-
Whether this render object is waiting for layout.
no setterinherited
- debugNeedsPaint → bool
-
Whether this render object is waiting for paint.
no setterinherited
- hashCode → int
-
The hash code for this object.
no setterinherited
- height ↔ int
-
Height in terminal cells, assigned during layout.
getter/setter pairinherited
- parent → RenderObject?
-
Parent RenderObject in the tree.
no setterinherited
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- size ↔ Size
-
The current size of this box, or Size.zero if not laid out
getter/setter pairinherited
- width ↔ int
-
Width in terminal cells, assigned during layout.
getter/setter pairinherited
- x ↔ int
-
Horizontal position in terminal cells, relative to the parent.
getter/setter pairinherited
- y ↔ int
-
Vertical position in terminal cells, relative to the parent.
getter/setter pairinherited
Methods
-
adoptChild(
RenderObject child) → void -
Add a child to this render object
inherited
-
detach(
) → void -
Called when the render object is detached from the render tree.
inherited
-
dropChild(
RenderObject child) → void -
Remove a child from this render object
inherited
-
hitTest(
HitTestResult result, Offset position) → bool -
Hit-test this render object using
positionin local coordinates.inherited -
hitTestChildren(
HitTestResult result, Offset position) → bool -
Hit-test children in reverse paint order.
inherited
-
hitTestSelf(
Offset position) → bool -
Whether this box should add itself to a hit-test path.
inherited
-
layout(
Constraints constraints) → void -
Entry point for layout.
inherited
-
markNeedsLayout(
) → void -
Mark this render object as needing layout and paint.
inherited
-
markNeedsPaint(
) → void -
Mark this render object as needing paint.
inherited
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
paint(
PaintingContext context, Offset offset) → void -
Default paint implementation.
inherited
-
performBoxLayout(
BoxConstraints constraints) → void -
Perform layout with typed box constraints
override
-
performLayout(
Constraints constraints) → void -
Perform layout with box constraints
inherited
-
positionChild(
RenderBox child, int x, int y) → void -
Position a child within this box
inherited
-
setChild(
RenderObject? newChild) → void -
Set the child render object. Idempotent: passing the current child or
one already adopted as this object's child is a no-op.
override
-
toString(
) → String -
A string representation of this object.
inherited
-
visitChildren(
void visitor(RenderObject child)) → void -
Visit all children with a callback
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited