TreeView<T> class

A widget that displays TreeViewNodes that expand and collapse in a vertically and horizontally scrolling TreeViewport.

The type T correlates to the type of TreeView and TreeViewNode, representing the type of TreeViewNode.content.

The rows of the tree are laid out on demand by the TreeViewport's render object, using TreeView.treeNodeBuilder. This will only be called for the nodes that are visible, or within the TreeViewport.cacheExtent.

The TreeView.treeNodeBuilder returns the Widget that represents the given TreeViewNode.

The TreeView.treeRowBuilder returns a TreeRow, which provides details about the row such as the TreeRowExtent, as well as any TreeRow.recognizerFactories, TreeRowDecorations, and more.

Providing a TreeController will enable querying and controlling the state of nodes in the tree.

Each active node of the tree will have a TreeVicinity, representing the resolved row index of the node, based on what nodes are active, as well as the depth.

A TreeView only supports a vertical axis direction of AxisDirection.down and a horizontal axis direction of AxisDirection.right.

Inheritance

Constructors

TreeView({Key? key, required List<TreeViewNode<T>> tree, TreeViewNodeBuilder<T> treeNodeBuilder = TreeView.defaultTreeNodeBuilder, TreeViewRowBuilder<T> treeRowBuilder = TreeView.defaultTreeRowBuilder, TreeViewController? controller, TreeViewNodeCallback<T>? onNodeToggle, AnimationStyle? toggleAnimationStyle, TreeViewIndentationType indentation = TreeViewIndentationType.standard, bool? primary, Axis mainAxis = Axis.vertical, ScrollableDetails verticalDetails = const ScrollableDetails.vertical(), ScrollableDetails horizontalDetails = const ScrollableDetails.horizontal(), double? cacheExtent, DiagonalDragBehavior diagonalDragBehavior = DiagonalDragBehavior.none, DragStartBehavior dragStartBehavior = DragStartBehavior.start, ScrollViewKeyboardDismissBehavior keyboardDismissBehavior = ScrollViewKeyboardDismissBehavior.manual, Clip clipBehavior = Clip.hardEdge, bool addAutomaticKeepAlives = true, bool addRepaintBoundaries = true}): Creates an instance of a TreeView for displaying TreeViewNodes that animate expanding and collapsing of nodes.

Properties

addAutomaticKeepAlives → bool: Whether to wrap each row of the tree in an AutomaticKeepAlive.
final
addRepaintBoundaries → bool: Whether to wrap each row in a RepaintBoundary.
final
cacheExtent → double?: The TreeViewport has an area before and after the visible area to cache rows that are about to become visible when the user scrolls.
final
clipBehavior → Clip: The bounds of the TreeViewport will be clipped (or not) according to this option.
final
controller → TreeViewController?: If provided, the controller can be used to expand and collapse TreeViewNodes, or lookup information about the current state of the TreeView.
final
diagonalDragBehavior → DiagonalDragBehavior: Whether scrolling gestures should lock to one axes, allow free movement in both axes, or be evaluated on a weighted scale.
final
dragStartBehavior → DragStartBehavior: Determines the way that drag start behavior is handled.
final
hashCode → int: The hash code for this object.
no setterinherited
horizontalDetails → ScrollableDetails: The configuration of the horizontal Scrollable.
final
indentation → TreeViewIndentationType: The number of pixels children will be offset by in the cross axis based on their TreeViewNode.depth.
final
key → Key?: Controls how one widget replaces another widget in the tree.
finalinherited
keyboardDismissBehavior → ScrollViewKeyboardDismissBehavior: ScrollViewKeyboardDismissBehavior the defines how this ScrollView will dismiss the keyboard automatically.
final
mainAxis → Axis: The main axis of the two.
final
onNodeToggle → TreeViewNodeCallback<T>?: Called when a TreeViewNode is toggled to expand or collapse.
final
primary → bool?: Whether this is the primary scroll view associated with the parent PrimaryScrollController.
final
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
toggleAnimationStyle → AnimationStyle?: The default AnimationStyle for expanding and collapsing nodes in the TreeView.
final
tree → List<TreeViewNode<T>>: The list of TreeViewNodes that may be displayed in the TreeView.
final
treeNodeBuilder → TreeViewNodeBuilder<T>: Called to build an entry of the TreeView for the given TreeViewNode.
final
treeRowBuilder → TreeViewRowBuilder<T>: Builds the TreeRow that describes the row for the provided TreeViewNode.
final
verticalDetails → ScrollableDetails: The configuration of the vertical Scrollable.
final

Methods

createElement() → StatefulElement: Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<TreeView<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}) → 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

Static Properties

defaultToggleAnimationStyle ↔ AnimationStyle: The default AnimationStyle used for node expand and collapse animations, when one has not been provided in toggleAnimationStyle.
getter/setter pair

Static Methods

defaultTreeNodeBuilder(BuildContext context, TreeViewNode<Object?> node, AnimationStyle toggleAnimationStyle) → Widget: Default builder for the widget representing a given TreeViewNode in the tree.
defaultTreeRowBuilder(TreeViewNode<Object?> node) → TreeRow: Returns the fixed height, default TreeRow for rows in the tree, which is 40 pixels.
wrapChildToToggleNode({required TreeViewNode<Object?> node, required Widget child}) → Widget: A wrapper method for triggering the expansion or collapse of a TreeViewNode.

Constants

defaultAnimationCurve → const Curve: A default of Curves.linear, which is used in the tree's expanding and collapsing node animation.
defaultAnimationDuration → const Duration: A default Duration of 150 milliseconds, which is used in the tree's expanding and collapsing node animation.