Key class Null safety

A Key is an identifier for Widgets, Elements and SemanticsNodes.

A new widget will only be used to update an existing element if its key is the same as the key of the current widget associated with the element.

Keys must be unique amongst the Elements with the same parent.

Subclasses of Key should either subclass LocalKey or GlobalKey.

See also:

  • Widget.key, which discusses how widgets use keys.
Implementers
Annotations

Constructors

Key(String value)
Construct a ValueKey<String> with the given String.
const
factory
Key.empty()
Default constructor, used by subclasses.
const

Properties

hashCode int
The hash code for this object.
read-onlyinherited
runtimeType Type
A representation of the runtime type of the object.
read-onlyinherited

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
inherited
toString() String
A string representation of this object.
inherited

Operators

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