Displays a menu when pressed and calls onSelected when the menu is dismissed because an item was selected. The value passed to onSelected is the value of the selected menu item.

One of child or icon may be provided, but not both. If icon is provided, then PopupMenuButton behaves like an IconButton.

If both are null, then a standard overflow icon is created (depending on the platform).

Sample code

This example shows a menu with four items, selecting between an enum's values and setting a _selection field based on the selection.

// This is the type used by the popup menu below.
enum WhyFarther { harder, smarter, selfStarter, tradingCharter }

// This menu button widget updates a _selection field (of type WhyFarther,
// not shown here).
new PopupMenuButton<WhyFarther>(
  onSelected: (WhyFarther result) { setState(() { _selection = result; }); },
  itemBuilder: (BuildContext context) => <PopupMenuEntry<WhyFarther>>[
    const PopupMenuItem<WhyFarther>(
      value: WhyFarther.harder,
      child: const Text('Working a lot harder'),
    ),
    const PopupMenuItem<WhyFarther>(
      value: WhyFarther.smarter,
      child: const Text('Being a lot smarter'),
    ),
    const PopupMenuItem<WhyFarther>(
      value: WhyFarther.selfStarter,
      child: const Text('Being a self-starter'),
    ),
    const PopupMenuItem<WhyFarther>(
      value: WhyFarther.tradingCharter,
      child: const Text('Placed in charge of trading charter'),
    ),
  ],
)

See also:

Inheritance

Constructors

PopupMenuButton({Key key, @required PopupMenuItemBuilder<T> itemBuilder, T initialValue, PopupMenuItemSelected<T> onSelected, String tooltip: 'Show menu', double elevation: 8.0, EdgeInsets padding: const EdgeInsets.all(8.0), Widget child, Icon icon })
Creates a button that shows a popup menu. [...]
const

Properties

child Widget
If provided, the widget used for this button.
final
elevation double
The z-coordinate at which to place the menu when open. This controls the size of the shadow below the menu. [...]
final
icon Icon
If provided, the icon used for this button.
final
initialValue → T
The value of the menu item, if any, that should be highlighted when the menu opens.
final
itemBuilder PopupMenuItemBuilder<T>
Called when the button is pressed to create the items to show in the menu.
final
onSelected PopupMenuItemSelected<T>
Called when the user selects a value from the popup menu created by this button.
final
padding EdgeInsets
Matches IconButton's 8 dps padding by default. In some cases, notably where this button appears as the trailing element of a list item, it's useful to be able to set the padding to zero.
final
tooltip String
Text that describes the action that will occur when the button is pressed. [...]
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() → _PopupMenuButtonState<T>
Creates the mutable state for this widget at a given location in the tree. [...]
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 description) → 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 toStringDeep. [...]
inherited
toString() String
Returns a string representation of this object.
inherited
toStringDeep([String prefixLineOne = '', String prefixOtherLines ]) String
Returns a string representation of this node and its descendants. [...]
inherited
toStringShallow([String joiner = ', ' ]) String
Returns a one-line detailed description of the object. [...]
inherited
toStringShort() String
A short, textual description of this widget.
inherited

Operators

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