Visibility class Null safety
Whether to show or hide a child.
By default, the visible property controls whether the child is included in the subtree or not; when it is not visible, the replacement child (typically a zero-sized box) is included instead.
A variety of flags can be used to tweak exactly how the child is hidden. (Changing the flags dynamically is discouraged, as it can cause the child subtree to be rebuilt, with any state in the subtree being discarded. Typically, only the visible flag is changed dynamically.)
These widgets provide some of the facets of this one:
- Opacity, which can stop its child from being painted.
- Offstage, which can stop its child from being laid out or painted.
- TickerMode, which can stop its child from being animated.
- ExcludeSemantics, which can hide the child from accessibility tools.
- IgnorePointer, which can disable touch interactions with the child.
Using this widget is not necessary to hide children. The simplest way to hide a child is just to not include it, or, if a child must be given (e.g. because the parent is a StatelessWidget) then to use SizedBox.shrink instead of the child that would otherwise be included.
See also:
- AnimatedSwitcher, which can fade from one child to the next as the subtree changes.
- AnimatedCrossFade, which can fade between two specific children.
- Inheritance
-
- Object
- DiagnosticableTree
- Widget
- StatelessWidget
- Visibility
Constructors
- Visibility({Key? key, required Widget child, Widget replacement = const SizedBox.shrink(), bool visible = true, bool maintainState = false, bool maintainAnimation = false, bool maintainSize = false, bool maintainSemantics = false, bool maintainInteractivity = false})
-
Control whether the given child is visible.
const
Properties
- child → Widget
-
The widget to show or hide, as controlled by visible.
final
- hashCode → int
- The hash code for this object.
- key → Key?
-
Controls how one widget replaces another widget in the tree.
finalinherited
- maintainAnimation → bool
-
Whether to maintain animations within the child subtree when it is
not visible.
final
- maintainInteractivity → bool
-
Whether to allow the widget to be interactive when hidden.
final
- maintainSemantics → bool
-
Whether to maintain the semantics for the widget when it is hidden (e.g.
for accessibility).
final
- maintainSize → bool
-
Whether to maintain space for where the widget would have been.
final
- maintainState → bool
-
Whether to maintain the State objects of the child subtree when it is
not visible.
final
- replacement → Widget
-
The widget to use when the child is not visible, assuming that none of
the
maintainflags (in particular, maintainState) are set.final - runtimeType → Type
-
A representation of the runtime type of the object.
read-onlyinherited
- visible → bool
-
Switches between showing the child or hiding it.
final
Methods
-
build(
BuildContext context) → Widget -
Describes the part of the user interface represented by this widget.
override
-
createElement(
) → StatelessElement -
Creates a StatelessElement to manage this widget's location in the tree.
inherited
-
debugDescribeChildren(
) → List< DiagnosticsNode> -
Returns a list of
DiagnosticsNodeobjects describing this node's children.protected">@protectedinherited -
debugFillProperties(
DiagnosticPropertiesBuilder properties) → void -
Add additional properties associated with the node.
override
-
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.info}) → String -
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 ==(
Object other) → bool -
The equality operator.
nonVirtual">@nonVirtualinherited