RenderSliverMultiBoxAdaptor class

A sliver with multiple box children.

RenderSliverMultiBoxAdaptor is a base class for slivers that have multiple box children. The children are managed by a RenderSliverBoxChildManager, which lets subclasses create children lazily during layout. Typically subclasses will create only those children that are actually needed to fill the SliverConstraints.remainingPaintExtent.

The contract for adding and removing children from this render object is more strict than for normal render objects:

Children can be removed except during a layout pass if they have already been laid out during that layout pass.
Children cannot be added except during a call to childManager, and then only if there is no child corresponding to that index (or the child child corresponding to that index was first removed).

Constructors

RenderSliverMultiBoxAdaptor({@required RenderSliverBoxChildManager childManager }): Creates a sliver with multiple box children. [...]

Properties

childManager → RenderSliverBoxChildManager: The delegate that manages the children of this object. [...]
@protected, read-only
alwaysNeedsCompositing → bool: Whether this render object always needs compositing. [...]
@protected, read-only, inherited
attached → bool: Whether this node is in a tree whose root is attached to something. [...]
read-only, inherited
centerOffsetAdjustment → double: For a center sliver, the distance before the absolute zero scroll offset that this sliver can cover. [...]
read-only, inherited
childCount → int: The number of children.
read-only, inherited
constraints → SliverConstraints: The layout constraints most recently supplied by the parent.
read-only, inherited
debugCanParentUseSize → bool: Whether the parent render object is permitted to use this render object's size. [...]
read-only, inherited
debugCreator ↔ dynamic: The object responsible for creating this render object. [...]
read / write, inherited
debugDoingThisLayout → bool: Whether performLayout for this render object is currently running. [...]
read-only, inherited
debugDoingThisPaint → bool: Whether paint for this render object is currently running. [...]
read-only, inherited
debugDoingThisResize → bool: Whether performResize for this render object is currently running. [...]
read-only, inherited
debugLayer → OffsetLayer: In debug mode, the compositing layer that this render object uses to repaint. [...]
read-only, inherited
debugNeedsLayout → bool: Whether this render object's layout information is dirty. [...]
read-only, inherited
debugNeedsPaint → bool: Whether this render object's paint information is dirty. [...]
read-only, inherited
debugSemantics → SemanticsNode: The semantics of this render object. [...]
read-only, inherited
depth → int: The depth of this node in the tree. [...]
read-only, inherited
firstChild → RenderBox: The first child in the child list.
read-only, inherited
geometry ↔ SliverGeometry: The amount of space this sliver occupies. [...]
read / write, inherited
hashCode → int: The hash code for this object. [...]
read-only, inherited
isRepaintBoundary → bool: Whether this render object repaints separately from its parent. [...]
read-only, inherited
lastChild → RenderBox: The last child in the child list.
read-only, inherited
layer → OffsetLayer: The compositing layer that this render object uses to repaint. [...]
read-only, inherited
needsCompositing → bool: Whether we or one of our descendants has a compositing layer. [...]
read-only, inherited
owner → PipelineOwner: The owner for this node (null if unattached). [...]
read-only, inherited
paintBounds → Rect: An estimate of the bounds within which this render object will paint. Useful for debugging flags such as debugPaintLayerBordersEnabled. [...]
read-only, inherited
parent → AbstractNode: The parent of this node in the tree.
read-only, inherited
parentData ↔ ParentData: Data for use by the parent render object. [...]
read / write, inherited
runtimeType → Type: A representation of the runtime type of the object.
read-only, inherited
semanticBounds → Rect: The bounding box, in the local coordinate system, of this object, for accessibility purposes.
read-only, inherited
sizedByParent → bool: Whether the constraints are the only input to the sizing algorithm (in particular, child nodes have no impact). [...]
@protected, read-only, inherited

Methods

addInitialChild({int index: 0, double layoutOffset: 0.0 }) → bool: Called during layout to create and add the child with the given index and scroll offset. [...]
@protected
adoptChild(covariant RenderObject child) → void: Called by subclasses when they decide a render object is a child. [...]
override
applyPaintTransform(covariant RenderObject child, Matrix4 transform) → void: Applies the transform that would be applied when painting the given child to the given matrix. [...]
override
attach(covariant PipelineOwner owner) → void: Mark this node as attached to the given owner. [...]
override
childMainAxisPosition(covariant RenderBox 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. [...]
override
collectGarbage(int leadingGarbage, int trailingGarbage) → void: Called after layout with the number of children that can be garbage collected at the head and tail of the child list. [...]
@protected
debugAssertChildListIsNonEmptyAndContiguous() → bool: Asserts that the reified child list is not empty and has a contiguous sequence of indices. [...]
debugDescribeChildren() → List<DiagnosticsNode>: Returns a list of DiagnosticsNode objects describing this node's children. [...]
override
debugFillProperties(DiagnosticPropertiesBuilder properties) → void: Add additional properties associated with the node. [...]
override
detach() → void: Mark this node as detached. [...]
override
hitTestChildren(HitTestResult result, { double mainAxisPosition, double crossAxisPosition }) → bool: Override this method to check whether any children are located at the given position. [...]
override
indexOf(RenderBox child) → int: Returns the index of the given child, as given by the SliverMultiBoxAdaptorParentData.index field of the child's parentData.
insert(RenderBox child, { RenderBox after }) → void: Insert child into this render object's child list after the given child. [...]
override
insertAndLayoutChild(BoxConstraints childConstraints, { RenderBox after, bool parentUsesSize: false }) → RenderBox: Called during layout to create, add, and layout the child after the given child. [...]
@protected
insertAndLayoutLeadingChild(BoxConstraints childConstraints, { bool parentUsesSize: false }) → RenderBox: Called during layout to create, add, and layout the child before firstChild. [...]
@protected
paint(PaintingContext context, Offset offset) → void: Paint this render object into the given context at the given offset. [...]
override
paintExtentOf(RenderBox child) → double: Returns the dimension of the given child in the main axis, as given by the child's RenderBox.size property. This is only valid after layout.
@protected
redepthChildren() → void: Adjust the depth of this node's children, if any. [...]
override
remove(RenderBox child) → void: Remove this child from the child list. [...]
override
removeAll() → void: Remove all their children from this render object's child list. [...]
override
setupParentData(covariant RenderObject child) → void: Alerts the developer that the child's parentData needs to be of type KeepAliveParentDataMixin.
override
visitChildren(RenderObjectVisitor visitor) → void: Calls visitor for each immediate child of this render object. [...]
override
add(RenderBox child) → void: Append child to the end of this render object's child list.
inherited
addAll(List<RenderBox> children) → void: Add all the children to the end of this render object's child list.
inherited
applyPaintTransformForBoxChild(RenderBox child, Matrix4 transform) → void: Utility function for applyPaintTransform for use when the children are RenderBox widgets. [...]
@protected, inherited
assembleSemanticsNode(SemanticsNode node, SemanticsConfiguration config, Iterable<SemanticsNode> children) → void: Assemble the SemanticsNode for this RenderObject. [...]
inherited
calculateCacheOffset(SliverConstraints constraints, { double from, 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, { double from, 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
childAfter(RenderBox child) → RenderBox: The next child after the given child in the child list.
inherited
childBefore(RenderBox child) → RenderBox: The previous child before the given child in the child list.
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. [...]
@protected, inherited
clearSemantics() → void: Removes all semantics from this render object and its descendants. [...]
@mustCallSuper, 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 in checked mode and only when needsLayout is false. If the constraints are not met, it should assert or throw an exception.
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 checked 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 checked 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
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. [...]
@protected, inherited
dropChild(covariant RenderObject child) → void: Called by subclasses when they decide a render object is no longer a child. [...]
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. [...]
@protected, inherited
getTransformTo(RenderObject ancestor) → Matrix4: Applies the paint transform up the tree to ancestor. [...]
inherited
handleEvent(PointerEvent event, covariant SliverHitTestEntry entry) → void: Override this method to handle pointer events that hit this render object.
inherited
hitTest(HitTestResult result, { double mainAxisPosition, double crossAxisPosition }) → bool: Determines the set of render objects located at the given position. [...]
inherited
hitTestBoxChild(HitTestResult result, RenderBox child, { double mainAxisPosition, double crossAxisPosition }) → bool: Utility function for hitTestChildren for use when the children are RenderBox widgets. [...]
@protected, inherited
hitTestSelf({double mainAxisPosition, double crossAxisPosition }) → bool: Override this method if this render object can be hit even if its children were not hit. [...]
@protected, 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. [...]
@protected, inherited
layout(Constraints constraints, { bool parentUsesSize: false }) → void: Compute the layout for this render object. [...]
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. [...]
@protected, inherited
move(RenderBox child, { RenderBox after }) → void: Move this child in the child list to be before the given child. [...]
inherited
noSuchMethod(Invocation invocation) → dynamic: Invoked when a non-existent method or property is accessed. [...]
inherited
performLayout() → void: Do the work of computing the layout for this render object. [...]
@protected, inherited
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(AbstractNode child) → void: Adjust the depth of the given child to be greater than this node's own depth. [...]
@protected, 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
rotate({int oldAngle, int newAngle, Duration time }) → void: Rotate this render object (not yet implemented).
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
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 toStringDeep. [...]
inherited
toString({DiagnosticLevel minLevel }) → String: Returns a string representation of this object.
inherited
toStringDeep({String prefixLineOne: '', String prefixOtherLines: '', DiagnosticLevel minLevel: DiagnosticLevel.debug }) → 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
visitChildrenForSemantics(RenderObjectVisitor visitor) → void: Called when collecting the semantics of this node. [...]
inherited

Operators

operator ==(dynamic other) → bool: The equality operator. [...]
inherited

rendering library

RenderSliverMultiBoxAdaptor class

Constructors

Properties

Methods

Operators