RenderProxySliver class abstract

A base class for sliver render objects that resemble their children.

A proxy sliver has a single child and mimics all the properties of that child by calling through to the child for each function in the render sliver protocol. For example, a proxy sliver determines its geometry by asking its sliver child to layout with the same constraints and then matching the geometry.

A proxy sliver isn't useful on its own because you might as well just replace the proxy sliver with its child. However, RenderProxySliver is a useful base class for render objects that wish to mimic most, but not all, of the properties of their sliver child.

Constructors

RenderProxySliver([RenderSliver? child]): Creates a proxy render sliver.

Properties

alwaysNeedsCompositing → bool: Whether this render object always needs compositing.
no setterinherited
attached → bool: Whether the render tree this render object belongs to is attached to a PipelineOwner.
no setterinherited
centerOffsetAdjustment → double: For a center sliver, the distance before the absolute zero scroll offset that this sliver can cover.
no setterinherited
child ↔ RenderSliver?: The render object's unique child.
getter/setter pairinherited
constraints → SliverConstraints: The layout constraints most recently supplied by the parent.
no setterinherited
debugCanParentUseSize → bool: Whether the parent render object is permitted to use this render object's size.
no setterinherited
debugCreator ↔ Object?: The object responsible for creating this render object.
getter/setter pairinherited
debugDisposed → bool?: Whether this has been disposed.
no setterinherited
debugDoingThisLayout → bool: Whether performLayout for this render object is currently running.
no setterinherited
debugDoingThisLayoutWithCallback → bool: Whether invokeLayoutCallback for this render object is currently running.
no setterinherited
debugDoingThisPaint → bool: Whether paint for this render object is currently running.
no setterinherited
debugDoingThisResize → bool: Whether performResize for this render object is currently running.
no setterinherited
debugLayer → ContainerLayer?: In debug mode, the compositing layer that this render object uses to repaint.
no setterinherited
debugLayoutParent → RenderObject?: The RenderObject that's expected to call layout on this RenderObject in its performLayout implementation.
no setterinherited
debugNeedsCompositedLayerUpdate → bool: Whether this render object's layer information is dirty.
no setterinherited
debugNeedsLayout → bool: Whether this render object's layout information is dirty.
no setterinherited
debugNeedsPaint → bool: Whether this render object's paint information is dirty.
no setterinherited
debugNeedsSemanticsUpdate → bool: Whether the semantics of this render object is dirty and await the update.
no setterinherited
debugSemantics → SemanticsNode?: The semantics of this render object.
no setterinherited
depth → int: The depth of this render object in the render tree.
no setterinherited
geometry ↔ SliverGeometry?: The amount of space this sliver occupies.
getter/setter pairinherited
hashCode → int: The hash code for this object.
no setterinherited
isRepaintBoundary → bool: Whether this render object repaints separately from its parent.
no setterinherited
layer ↔ ContainerLayer?: The compositing layer that this render object uses to repaint.
getter/setter pairinherited
needsCompositing → bool: Whether we or one of our descendants has a compositing layer.
no setterinherited
owner → PipelineOwner?: The owner for this render object (null if unattached).
no setterinherited
paintBounds → Rect: An estimate of the bounds within which this render object will paint. Useful for debugging flags such as debugPaintLayerBordersEnabled.
no setterinherited
parent → RenderObject?: The parent of this render object in the render tree.
no setterinherited
parentData ↔ ParentData?: Data for use by the parent render object.
getter/setter pairinherited
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
semanticBounds → Rect: The bounding box, in the local coordinate system, of this object, for accessibility purposes.
no setterinherited
semanticsParent → RenderObject?: The semantics parent of this render object in the semantics tree.
no setterinherited
sizedByParent → bool: Whether the constraints are the only input to the sizing algorithm (in particular, child nodes have no impact).
no setterinherited

Methods

adoptChild(RenderObject child) → void: Called by subclasses when they decide a render object is a child.
inherited
applyPaintTransform(covariant RenderObject child, Matrix4 transform) → void: Applies the transform that would be applied when painting the given child to the given matrix.
override
assembleSemanticsNode(SemanticsNode node, SemanticsConfiguration config, Iterable<SemanticsNode> children) → void: Assemble the SemanticsNode for this RenderObject.
inherited
attach(PipelineOwner owner) → void: Mark this render object as attached to the given owner.
inherited
calculateCacheOffset(SliverConstraints constraints, {required double from, required double to}) → double: Computes the portion of the region from from to to that is within the cache extent of the viewport, assuming that only the region from the SliverConstraints.cacheOrigin that is SliverConstraints.remainingCacheExtent high is visible, and that the relationship between scroll offsets and paint offsets is linear.
inherited
calculatePaintOffset(SliverConstraints constraints, {required double from, required double to}) → double: Computes the portion of the region from from to to that is visible, assuming that only the region from the SliverConstraints.scrollOffset that is SliverConstraints.remainingPaintExtent high is visible, and that the relationship between scroll offsets and paint offsets is linear.
inherited
childCrossAxisPosition(covariant RenderObject child) → double: Returns the distance along the cross axis from the zero of the cross axis in this sliver's paint coordinate space to the nearest side of the given child.
inherited
childMainAxisPosition(covariant RenderSliver child) → double: Returns the distance from the leading visible edge of the sliver to the side of the given child closest to that edge.
override
childScrollOffset(covariant RenderObject child) → double?: Returns the scroll offset for the leading edge of the given child.
inherited
clearSemantics() → void: Removes all semantics from this render object and its descendants.
inherited
debugAssertDoesMeetConstraints() → void: Verify that the object's constraints are being met. Override this function in a subclass to verify that your state matches the constraints object. This function is only called when asserts are enabled (i.e. in debug mode) and only when needsLayout is false. If the constraints are not met, it should assert or throw an exception.
inherited
debugDescribeChildren() → List<DiagnosticsNode>: Returns a list of DiagnosticsNode objects describing this node's children.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void: Add additional properties associated with the node.
inherited
debugPaint(PaintingContext context, Offset offset) → void: Override this method to paint debugging information.
inherited
debugRegisterRepaintBoundaryPaint({bool includedParent = true, bool includedChild = false}) → void: Called, in debug mode, if isRepaintBoundary is true, when either the this render object or its parent attempt to paint.
inherited
debugResetSize() → void: If a subclass has a "size" (the state controlled by parentUsesSize, whatever it is in the subclass, e.g. the actual size property of RenderBox), and the subclass verifies that in debug mode this "size" property isn't used when debugCanParentUseSize isn't set, then that subclass should override debugResetSize to reapply the current values of debugCanParentUseSize to that state.
inherited
debugValidateChild(RenderObject child) → bool: Checks whether the given render object has the correct runtimeType to be a child of this render object.
inherited
describeApproximatePaintClip(covariant RenderObject child) → Rect?: Returns a rect in this object's coordinate system that describes the approximate bounding box of the clip rect that would be applied to the given child during the paint phase, if any.
inherited
describeForError(String name, {DiagnosticsTreeStyle style = DiagnosticsTreeStyle.shallow}) → DiagnosticsNode: Adds a debug representation of a RenderObject optimized for including in error messages.
inherited
describeSemanticsClip(covariant RenderObject? child) → Rect?: Returns a rect in this object's coordinate system that describes which SemanticsNodes produced by the child should be included in the semantics tree. SemanticsNodes from the child that are positioned outside of this rect will be dropped. Child SemanticsNodes that are positioned inside this rect, but outside of describeApproximatePaintClip will be included in the tree marked as hidden. Child SemanticsNodes that are inside of both rect will be included in the tree as regular nodes.
inherited
describeSemanticsConfiguration(SemanticsConfiguration config) → void: Report the semantics of this node, for example for accessibility purposes.
inherited
detach() → void: Mark this render object as detached from its PipelineOwner.
inherited
dispose() → void: Release any resources held by this render object.
inherited
dropChild(RenderObject child) → void: Called by subclasses when they decide a render object is no longer a child.
inherited
getAbsoluteSize() → Size: This returns the absolute Size of the sliver.
inherited
getAbsoluteSizeRelativeToOrigin() → Size: This returns a Size with dimensions relative to the leading edge of the sliver, specifically the same offset that is given to the paint method. This means that the dimensions may be negative.
inherited
getTransformTo(RenderObject? target) → Matrix4: Applies the paint transform from this RenderObject to the target RenderObject.
inherited
handleEvent(PointerEvent event, covariant SliverHitTestEntry entry) → void: Override this method to handle pointer events that hit this render object.
inherited
hitTest(SliverHitTestResult result, {required double mainAxisPosition, required double crossAxisPosition}) → bool: Determines the set of render objects located at the given position.
inherited
hitTestChildren(SliverHitTestResult result, {required double mainAxisPosition, required double crossAxisPosition}) → bool: Override this method to check whether any children are located at the given position.
override
hitTestSelf({required double mainAxisPosition, required double crossAxisPosition}) → bool: Override this method if this render object can be hit even if its children were not hit.
inherited
invokeLayoutCallback<T extends Constraints>(LayoutCallback<T> callback) → void: Allows mutations to be made to this object's child list (and any descendants) as well as to any other dirty nodes in the render tree owned by the same PipelineOwner as this object. The callback argument is invoked synchronously, and the mutations are allowed only during that callback's execution.
inherited
layout(Constraints constraints, {bool parentUsesSize = false}) → void: Compute the layout for this render object.
inherited
markNeedsCompositedLayerUpdate() → void: Mark this render object as having changed a property on its composited layer.
inherited
markNeedsCompositingBitsUpdate() → void: Mark the compositing state for this render object as dirty.
inherited
markNeedsLayout() → void: Mark this render object's layout information as dirty, and either register this object with its PipelineOwner, or defer to the parent, depending on whether this object is a relayout boundary or not respectively.
inherited
markNeedsLayoutForSizedByParentChange() → void: Mark this render object's layout information as dirty (like markNeedsLayout), and additionally also handle any necessary work to handle the case where sizedByParent has changed value.
inherited
markNeedsPaint() → void: Mark this render object as having changed its visual appearance.
inherited
markNeedsSemanticsUpdate() → void: Mark this node as needing an update to its semantics description.
inherited
markParentNeedsLayout() → void: Mark this render object's layout information as dirty, and then defer to the parent.
inherited
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
paint(PaintingContext context, Offset offset) → void: Paint this render object into the given context at the given offset.
override
paintsChild(covariant RenderObject child) → bool: Whether the given child would be painted if paint were called.
inherited
performLayout() → void: Do the work of computing the layout for this render object.
override
performResize() → void: Updates the render objects size using only the constraints.
inherited
reassemble() → void: Cause the entire subtree rooted at the given RenderObject to be marked dirty for layout, paint, etc, so that the effects of a hot reload can be seen, or so that the effect of changing a global debug flag (such as debugPaintSizeEnabled) can be applied.
inherited
redepthChild(RenderObject child) → void: Adjust the depth of the given child to be greater than this node's own depth.
inherited
redepthChildren() → void: Adjust the depth of this node's children, if any.
inherited
replaceRootLayer(OffsetLayer rootLayer) → void: Replace the layer. This is only valid for the root of a render object subtree (whatever object scheduleInitialPaint was called on).
inherited
scheduleInitialLayout() → void: Bootstrap the rendering pipeline by scheduling the very first layout.
inherited
scheduleInitialPaint(ContainerLayer rootLayer) → void: Bootstrap the rendering pipeline by scheduling the very first paint.
inherited
scheduleInitialSemantics() → void: Bootstrap the semantics reporting mechanism by marking this node as needing a semantics update.
inherited
sendSemanticsEvent(SemanticsEvent semanticsEvent) → void: Sends a SemanticsEvent associated with this render object's SemanticsNode.
inherited
setupParentData(covariant RenderObject child) → void: Override to setup parent data correctly for your children.
override
showOnScreen({RenderObject? descendant, Rect? rect, Duration duration = Duration.zero, Curve curve = Curves.ease}) → void: Attempt to make (a portion of) this or a descendant RenderObject visible on screen.
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, int wrapWidth = 65}) → String: Returns a description of the tree rooted at this node. If the prefix argument is provided, then every line in the output will be prefixed by that string.
inherited
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String: Returns a one-line detailed description of the render object. This description is often somewhat long.
inherited
toStringShort() → String: Returns a human understandable name.
inherited
updateCompositedLayer({required covariant OffsetLayer? oldLayer}) → OffsetLayer: Update the composited layer owned by this render object.
inherited
visitChildren(RenderObjectVisitor visitor) → void: Calls visitor for each immediate child of this render object.
inherited
visitChildrenForSemantics(RenderObjectVisitor visitor) → void: Called when collecting the semantics of this node.
inherited

Operators

operator ==(Object other) → bool: The equality operator.
inherited

RenderProxySliver class abstract

Constructors

Properties

Methods

Operators

rendering library