AbstractNode class

Deprecated. Unused by the framework and will be removed in a future version of Flutter. If needed, inline any required functionality of this class directly in the subclass.

An abstract node in a tree.

AbstractNode has as notion of depth, attachment, and parent, but does not have a model for children.

When a subclass is changing the parent of a child, it should call either parent.adoptChild(child) or parent.dropChild(child) as appropriate. Subclasses can expose an API for manipulating the tree if desired (e.g. a setter for a child property, or an add() method to manipulate a list).

The current parent node is exposed by the parent property.

The current attachment state is exposed by attached. The root of any tree that is to be considered attached should be manually attached by calling attach. Other than that, the attach and detach methods should not be called directly; attachment is managed automatically by the aforementioned adoptChild and dropChild methods.

Subclasses that have children must override attach and detach as described in the documentation for those methods.

Nodes always have a depth greater than their ancestors'. There's no guarantee regarding depth between siblings. The depth of a node is used to ensure that nodes are processed in depth order. The depth of a child can be more than one greater than the depth of the parent, because the depth values are never decreased: all that matters is that it's greater than the parent. Consider a tree with a root node A, a child B, and a grandchild C. Initially, A will have depth 0, B depth 1, and C depth 2. If C is moved to be a child of A, sibling of B, then the numbers won't change. C's depth will still be 2. The depth is automatically maintained by the adoptChild and dropChild methods.

  • @Deprecated('If needed, inline any required functionality of AbstractNode in your class directly. ' 'This feature was deprecated after v3.12.0-4.0.pre.')




attached bool
Whether this node is in a tree whose root is attached to something.
no setter
depth int
The depth of this node in the tree.
no setter
hashCode int
The hash code for this object.
no setterinherited
owner Object?
The owner for this node (null if unattached).
no setter
parent AbstractNode?
The parent of this node in the tree.
no setter
runtimeType Type
A representation of the runtime type of the object.
no setterinherited


adoptChild(covariant AbstractNode child) → void
Mark the given node as being a child of this node.
attach(covariant Object owner) → void
Mark this node as attached to the given owner.
detach() → void
Mark this node as detached.
dropChild(covariant AbstractNode child) → void
Disconnect the given node from this node.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
redepthChild(AbstractNode child) → void
Adjust the depth of the given child to be greater than this node's own depth.
redepthChildren() → void
Adjust the depth of this node's children, if any.
toString() String
A string representation of this object.


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