FocusTraversalPolicy classabstract

Determines how focusable widgets are traversed within aFocusTraversalGroup.

The focus traversal policy is what determines which widget is "next","previous", or in a direction from the widget associated with the currentlyfocusedFocusNode (usually aFocus widget).

One of the pre-defined subclasses may be used, or define a custom policy tocreate a unique focus order.

When defining your own, your subclass should implementsortDescendants toprovide the order in which you would like the descendants to be traversed.

Constructors

FocusTraversalPolicy({TraversalRequestFocusCallback?requestFocusCallback}): Abstract const constructor. This constructor enables subclasses to provideconst constructors so that they can be used in const expressions.
const

Properties

hashCode→int: The hash code for this object.
no setterinherited
requestFocusCallback→TraversalRequestFocusCallback: The callback used to move the focus from one focus node to another whentraversing them using a keyboard. By default it requests focus on the nextnode and ensures the node is visible if it's in a scrollable.
final
runtimeType→Type: A representation of the runtime type of the object.
no setterinherited

Methods

changedScope({FocusNode?node,FocusScopeNode?oldScope})→ void: This is called whenever the givennode is re-parented into a new scope,so that the policy has a chance to update or invalidate any cached datathat it maintains per scope about the node.
debugFillProperties(DiagnosticPropertiesBuilderproperties)→ void: Add additional properties associated with the node.
inherited
findFirstFocus(FocusNodecurrentNode, {boolignoreCurrentFocus =false})→FocusNode?: Returns the node that should receive focus if focus is traversingforwards, and there is no current focus.
findFirstFocusInDirection(FocusNodecurrentNode,TraversalDirectiondirection)→FocusNode?: Returns the first node in the givendirection that should receive focusif there is no current focus in the scope to which thecurrentNodebelongs.
findLastFocus(FocusNodecurrentNode, {boolignoreCurrentFocus =false})→FocusNode: Returns the node that should receive focus if focus is traversingbackwards, and there is no current focus.
inDirection(FocusNodecurrentNode,TraversalDirectiondirection)→bool: Focuses the next widget in the givendirection in the focus scope thatcontains the givencurrentNode.
invalidateScopeData(FocusScopeNodenode)→ void: Clears the data associated with the givenFocusScopeNode for this object.
next(FocusNodecurrentNode)→bool: Focuses the next widget in the focus scope that contains the givencurrentNode.
noSuchMethod(Invocationinvocation)→ dynamic: Invoked when a nonexistent method or property is accessed.
inherited
previous(FocusNodecurrentNode)→bool: Focuses the previous widget in the focus scope that contains the givencurrentNode.
sortDescendants(Iterable<FocusNode>descendants,FocusNodecurrentNode)→Iterable<FocusNode>: Sorts the givendescendants into focus order.
toDiagnosticsNode({String?name,DiagnosticsTreeStyle?style})→DiagnosticsNode: Returns a debug representation of the object that is used by debuggingtools and byDiagnosticsNode.toStringDeep.
inherited
toString({DiagnosticLevelminLevel =DiagnosticLevel.info})→String: A string representation of this object.
inherited
toStringShort()→String: A brief description of this object, usually just theruntimeType and thehashCode.
inherited

Operators

operator ==(Objectother)→bool: The equality operator.
inherited

Static Methods

defaultTraversalRequestFocusCallback(FocusNodenode, {ScrollPositionAlignmentPolicy?alignmentPolicy,double?alignment,Duration?duration,Curve?curve})→ void: The default value forrequestFocusCallback.Requests focus fromnode and ensures the node is visibleby callingScrollable.ensureVisible.

Flutter
widgets
FocusTraversalPolicy class