Visibility class

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:

Inheritance

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
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 maintain flags (in particular, maintainState) are set. [...]
final
visible → bool
Switches between showing the child or hiding it. [...]
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

build(BuildContext context) → Widget
Describes the part of the user interface represented by this widget. [...]
override
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node. [...]
override
createElement() → StatelessElement
Creates a StatelessElement 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
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 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