operator == method Null safety
- Object other
Compare two widgets for equality.
When a widget is rebuilt with another that compares equal according
operator ==, it is assumed that the update is redundant and the
work to update that branch of the tree is skipped.
It is generally discouraged to override
operator == on any widget that
has children, since a correct implementation would have to defer to the
children's equality operator also, and that is an O(N²) operation: each
child would need to itself walk all its children, each step of the tree.
It is sometimes reasonable for a leaf widget (one with no children) to implement this method, if rebuilding the widget is known to be much more expensive than checking the widgets' parameters for equality and if the widget is expected to often be rebuilt with identical parameters.
In general, however, it is more efficient to cache the widgets used in a build method if it is known that they will not change.
@nonVirtual @override // ignore: avoid_equals_and_hash_code_on_mutable_classes, hash_and_equals bool operator ==(Object other) => identical(this, other);