ButtonBar class Null safety
An end-aligned row of buttons, laying out into a column if there is not enough horizontal space.
Places the buttons horizontally according to the buttonPadding. The children are laid out in a Row with MainAxisAlignment.end. When the Directionality is TextDirection.ltr, the button bar's children are right justified and the last child becomes the rightmost child. When the Directionality TextDirection.rtl the children are left justified and the last child becomes the leftmost child.
If the button bar's width exceeds the maximum width constraint on the widget, it aligns its buttons in a column. The key difference here is that the MainAxisAlignment will then be treated as a cross-axis/horizontal alignment. For example, if the buttons overflow and ButtonBar.alignment was set to MainAxisAlignment.start, the buttons would align to the horizontal start of the button bar.
The ButtonBar can be configured with a ButtonBarTheme. For any null property on the ButtonBar, the surrounding ButtonBarTheme's property will be used instead. If the ButtonBarTheme's property is null as well, the property will default to a value described in the field documentation below.
The children are wrapped in a ButtonTheme that is a copy of the surrounding ButtonTheme with the button properties overridden by the properties of the ButtonBar as described above. These properties include buttonTextTheme, buttonMinWidth, buttonHeight, buttonPadding, and buttonAlignedDropdown.
Used by Dialog to arrange the actions at the bottom of the dialog.
See also:
- TextButton, a simple flat button without a shadow.
- ElevatedButton, a filled button whose material elevates when pressed.
- OutlinedButton, a TextButton with a border outline.
- Card, at the bottom of which it is common to place a ButtonBar.
- Dialog, which uses a ButtonBar for its actions.
- ButtonBarTheme, which configures the ButtonBar.
- Inheritance
-
- Object
- DiagnosticableTree
- Widget
- StatelessWidget
- ButtonBar
Constructors
-
ButtonBar({Key? key, MainAxisAlignment? alignment, MainAxisSize? mainAxisSize, ButtonTextTheme? buttonTextTheme, double? buttonMinWidth, double? buttonHeight, EdgeInsetsGeometry? buttonPadding, bool? buttonAlignedDropdown, ButtonBarLayoutBehavior? layoutBehavior, VerticalDirection? overflowDirection, double? overflowButtonSpacing, List<
Widget> children = const <Widget>[]}) -
Creates a button bar.
const
Properties
- alignment → MainAxisAlignment?
-
How the children should be placed along the horizontal axis.
final
-
Overrides the surrounding ButtonThemeData.alignedDropdown to define whether
a DropdownButton menu's width will match the button's width.
final
-
Overrides the surrounding ButtonThemeData.height to define a button's
minimum height.
final
-
Overrides the surrounding ButtonThemeData.minWidth to define a button's
minimum width.
final
-
Overrides the surrounding ButtonThemeData.padding to define the padding
for a button's child (typically the button's label).
final
-
Overrides the surrounding ButtonBarThemeData.buttonTextTheme to define a
button's base colors, size, internal padding and shape.
final
-
children
→ List<
Widget> -
The buttons to arrange horizontally.
final
- hashCode → int
- The hash code for this object.
- key → Key?
-
Controls how one widget replaces another widget in the tree.
finalinherited
- layoutBehavior → ButtonBarLayoutBehavior?
-
Defines whether a ButtonBar should size itself with a minimum size
constraint or with padding.
final
- mainAxisSize → MainAxisSize?
-
How much horizontal space is available. See Row.mainAxisSize.
final
- overflowButtonSpacing → double?
-
The spacing between buttons when the button bar overflows.
final
- overflowDirection → VerticalDirection?
-
Defines the vertical direction of a ButtonBar's children if it
overflows.
final
- runtimeType → Type
-
A representation of the runtime type of the object.
read-onlyinherited
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
DiagnosticsNode
objects describing this node's children.protected">@protectedinherited -
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.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