FocusManager class
Manages the focus tree.
The focus tree keeps track of which FocusNode is the user's current keyboard focus. The widget that owns the FocusNode often listens for keyboard events.
The focus manager is responsible for holding the FocusScopeNode that is the root of the focus tree and tracking which FocusNode has the overall focus.
The FocusManager is held by the WidgetsBinding as
WidgetsBinding.focusManager, and can be conveniently accessed using the
focusManager global accessor.
To find the FocusScopeNode for a given BuildContext, use FocusScope.of.
The FocusManager knows nothing about FocusNodes other than the one that is currently focused (accessible via the primaryFocus global accessor). If a FocusScopeNode is removed, then the FocusManager will attempt to focus the next FocusScopeNode in the focus tree that it maintains, but if the current focus in that FocusScopeNode is null, it will stop there, and no FocusNode will have focus.
See also:
- FocusNode, which is a node in the focus tree that can receive focus.
- FocusScopeNode, which is a node in the focus tree used to collect subtrees into groups.
- Focus.of, which provides the nearest ancestor FocusNode for a given BuildContext.
- FocusScope.of, which provides the nearest ancestor FocusScopeNode for a given BuildContext.
- The
focusManagerand primaryFocus global accessors, for convenient access from anywhere to the current focus manager state.
- Mixed in types
Constructors
- FocusManager()
- Creates an object that manages the focus tree. [...]
Properties
- highlightMode → FocusHighlightMode
-
Indicates the current interaction mode for focus highlights. [...]
read-only
- highlightStrategy ↔ FocusHighlightStrategy
-
Sets the strategy by which highlightMode is determined. [...]
read / write
- primaryFocus → FocusNode
-
The node that currently has the primary focus.
read-only
- rootScope → FocusScopeNode
-
The root FocusScopeNode in the focus tree. [...]
final
- hashCode → int
-
The hash code for this object. [...]
read-only, inherited
- runtimeType → Type
-
A representation of the runtime type of the object.
read-only, inherited
Methods
-
addHighlightModeListener(
ValueChanged< FocusHighlightMode> listener) → void - Register a closure to be called when the FocusManager notifies its listeners that the value of highlightMode has changed.
-
debugDescribeChildren(
) → List< DiagnosticsNode> -
Returns a list of DiagnosticsNode objects describing this node's
children. [...]
override
-
debugFillProperties(
DiagnosticPropertiesBuilder properties) → void -
Add additional properties associated with the node. [...]
override
-
removeHighlightModeListener(
ValueChanged< FocusHighlightMode> listener) → void - Remove a previously registered closure from the list of closures that the FocusManager notifies.
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a non-existent method or property is accessed. [...]
inherited
-
toDiagnosticsNode(
{String name, DiagnosticsTreeStyle style }) → DiagnosticsNode -
Returns a debug representation of the object that is used by debugging
tools and by DiagnosticsNode.toStringDeep. [...]
inherited
-
toString(
{DiagnosticLevel minLevel: DiagnosticLevel.debug }) → String -
Returns a string representation of this object.
inherited
-
toStringDeep(
{String prefixLineOne: '', String prefixOtherLines, DiagnosticLevel minLevel: DiagnosticLevel.debug }) → String -
Returns a string representation of this node and its descendants. [...]
inherited
-
toStringShallow(
{String joiner: ', ', DiagnosticLevel minLevel: DiagnosticLevel.debug }) → String -
Returns a one-line detailed description of the object. [...]
inherited
-
toStringShort(
) → String -
A brief description of this object, usually just the runtimeType and the
hashCode. [...]
inherited
Operators
-
operator ==(
dynamic other) → bool -
The equality operator. [...]
inherited
Static Properties
- instance → FocusManager
-
Provides convenient access to the current FocusManager singleton from
the WidgetsBinding instance.
read-only