DropdownButton<T> class

A material design button for selecting from a list of items.

A dropdown button lets the user select from a number of items. The button shows the currently selected item as well as an arrow that opens a menu for selecting another item.

The type T is the type of the values the dropdown menu represents. All the entries in a given menu must represent values with consistent types. Typically, an enum is used. Each DropdownMenuItem in items must be specialized with that same type argument.

Requires one of its ancestors to be a Material widget.

See also:

Inheritance

Constructors

Creates a dropdown button. [...]

Properties

disabledHint → Widget
A message to show when the dropdown is disabled. [...]
final
elevation → int
The z-coordinate at which to place the menu when open. [...]
final
hint → Widget
Displayed if value is null.
final
iconSize → double
The size to use for the drop-down button's down arrow icon button. [...]
final
isDense → bool
Reduce the button's height. [...]
final
isExpanded → bool
Set the dropdown's inner contents to horizontally fill its parent. [...]
final
items → List<DropdownMenuItem<T>>
The list of possible items to select among.
final
onChanged → ValueChanged<T>
Called when the user selects an item.
final
style → TextStyle
The text style to use for text in the dropdown button and the dropdown menu that appears when you tap the button. [...]
final
value → T
The currently selected item, or null if no item has been selected. If value is null then the menu is popped up as if the first item was selected.
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() → _DropdownButtonState<T>
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 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