LexicalFocusOrder class Null safety

Can be given to a FocusTraversalOrder widget to use a String to assign a lexical order to a widget subtree that is using a OrderedTraversalPolicy to define the order in which widgets should be traversed with the keyboard.

This sorts strings using Dart's default string comparison, which is not locale-specific.

Only orders of the same type are comparable. If a set of widgets in the same FocusTraversalGroup contains orders that are not comparable with each other, it will assert, since the ordering between such keys is undefined. To avoid collisions, use a FocusTraversalGroup to group similarly ordered widgets together.

When overriding, FocusOrder.doCompare must be overridden instead of FocusOrder.compareTo, which calls FocusOrder.doCompare to do the actual comparison.

See also:



LexicalFocusOrder(String order)
Creates an object that describes a focus traversal order lexically.


hashCode int
The hash code for this object.
read-only, inherited
order String
The String that defines the lexical order to assign to the widget subtree using FocusTraversalOrder.
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited


compareTo(FocusOrder other) int
Compares this object to another Comparable.
@nonVirtual, inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
doCompare(covariant LexicalFocusOrder other) int
The subclass implementation called by compareTo to compare orders.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) String
A string representation of this object.
toStringShort() String
A brief description of this object, usually just the runtimeType and the hashCode.


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