FocusScope class

Establishes a scope in which widgets can receive focus.

The focus tree keeps track of which widget is the user's current focus. The focused widget often listens for keyboard events.

A focus scope does not itself receive focus but instead helps remember previous focus states. A scope is currently active when its node is the first focus of its parent scope. To activate a FocusScope, either use the autofocus property or explicitly make the node the first focus in the parent scope:

FocusScope.of(context).setFirstFocus(node);

If a FocusScope is removed from the widget tree, then the previously focused node will be focused, but only if the node is the same node object as in the previous frame. To assure this, you can use a GlobalKey to keep the FocusScope widget from being rebuilt from one frame to the next, or pass in the node from a parent that is not rebuilt. If there is no next sibling, then the parent scope node will be focused.

See also:

  • FocusScopeNode, which is the associated node in the focus tree.
  • FocusNode, which is a leaf node in the focus tree that can receive focus.
Inheritance

Constructors

FocusScope({Key key, @required FocusScopeNode node, bool autofocus: false, Widget child })
Creates a scope in which widgets can receive focus. [...]
const

Properties

autofocus bool
Whether this scope should attempt to become active when first added to the tree.
final
child Widget
The widget below this widget in the tree. [...]
final
node FocusScopeNode
Controls whether this scope is currently active.
final
hashCode int
The hash code for this object. [...]
read-only, inherited
key Key
Controls how one widget replaces another widget in the tree. [...]
final, inherited
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited

Methods

createState() → _FocusScopeState
Creates the mutable state for this widget at a given location in the tree. [...]
override
createElement() StatefulElement
Creates a StatefulElement to manage this widget's location in the tree. [...]
inherited
debugDescribeChildren() List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children. [...]
@protected, inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node. [...]
inherited
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 short, textual description of this widget.
inherited

Operators

operator ==(dynamic other) bool
The equality operator. [...]
inherited

Static Methods

ancestorsOf(BuildContext context) List<FocusScopeNode>
A list of the FocusScopeNodes for each FocusScope ancestor of the given BuildContext. The first element of the list is the nearest ancestor's FocusScopeNode. [...]
of(BuildContext context) FocusScopeNode
Returns the node of the FocusScope that most tightly encloses the given BuildContext. [...]