GridUnpinnedQuadrant<T extends DataGridRow> class

Renders the scrollable (unpinned) quadrant of the custom layout grid.

Scroll-driven updates are handled in two separate layers to avoid unnecessary widget rebuilds:

  • Widget layer (setState): called only when the set of visible cells changes (a row or column enters / leaves the viewport). Carry-over cells are reused from _cellCache — Flutter detects the identical widget instance and skips their build call entirely.

  • RenderObject layer (GridLayoutDelegate.relayout): fires on every hOffset / vOffset change and calls markNeedsLayout on the render object directly, so performLayout repositions children without touching the widget tree at all.

Result: most scroll frames produce zero hot widget rebuilds, and even boundary-crossing frames (cells entering / leaving) produce zero carry-over rebuilds.

Inheritance

Constructors

GridUnpinnedQuadrant({Key? key, required List<DataGridColumn<T>> columns, required List<int> unpinnedIndices, required double pinnedWidth, required double viewportWidth, required double viewportHeight, required List<double> displayOrder, required Map<double, T> rowsById, required int rowCount, required double rowHeight, required double cacheExtent, required ValueNotifier<double> hOffset, required ValueNotifier<double> vOffset})
const

Properties

cacheExtent → double
final
columns → List<DataGridColumn<T>>
final
displayOrder → List<double>
final
hashCode → int
The hash code for this object.
no setterinherited
hOffset → ValueNotifier<double>
final
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
pinnedWidth → double
final
rowCount → int
final
rowHeight → double
final
rowsById → Map<double, T>
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
unpinnedIndices → List<int>
final
viewportHeight → double
final
viewportWidth → double
final
vOffset → ValueNotifier<double>
final

Methods

createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<GridUnpinnedQuadrant<T>>
Creates the mutable state for this widget at a given location in the tree.
override
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
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
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 string representation of this node and its descendants.
inherited
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String
Returns a one-line detailed description of the object.
inherited
toStringShort() → String
A short, textual description of this widget.
inherited

Operators

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