Picker class

An iOS-styled picker.

Displays its children widgets on a wheel for selection and calls back when the currently selected item changes.

Can be used with showCupertinoModalPopup to display the picker modally at the bottom of the screen.

Sizes itself to its parent. All children are sized to the same size based on itemExtent.

By default, descendent texts are shown with CupertinoTextThemeData.pickerTextStyle.

Constructors

Picker({Key? key, double diameterRatio = _kDefaultDiameterRatio, Color backgroundColor = _kDefaultBackground, Color? lineColor = _kHighlighterBorder, double offAxisFraction = 0.0, bool useMagnifier = false, double magnification = 1.0, FixedExtentScrollController? scrollController, double squeeze = _kSqueeze, required double itemExtent, required ValueChanged<int> onSelectedItemChanged, required List<Widget> children, bool looping = false}): Creates a picker from a concrete list of children.
Picker.builder({Key? key, double diameterRatio = _kDefaultDiameterRatio, Color backgroundColor = _kDefaultBackground, Color? lineColor = _kHighlighterBorder, double offAxisFraction = 0.0, bool useMagnifier = false, double magnification = 1.0, FixedExtentScrollController? scrollController, double squeeze = _kSqueeze, required double itemExtent, required ValueChanged<int> onSelectedItemChanged, required IndexedWidgetBuilder itemBuilder, int? childCount}): Creates a picker from an IndexedWidgetBuilder callback where the builder is dynamically invoked during layout.

backgroundColor → Color: Background color behind the children.
final
childDelegate → ListWheelChildDelegate: A delegate that lazily instantiates children.
final
diameterRatio → double: Relative ratio between this picker's height and the simulated cylinder's diameter.
final
hashCode → int: The hash code for this object.
no setterinherited
itemExtent → double: The uniform height of all children.
final
key → Key?: Controls how one widget replaces another widget in the tree.
finalinherited
lineColor → Color?: 分割线颜色
final
magnification → double: final
offAxisFraction → double: final
onSelectedItemChanged → ValueChanged<int>: An option callback when the currently centered item changes.
final
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
scrollController → FixedExtentScrollController?: A FixedExtentScrollController to read and control the current item.
final
squeeze → double: Defaults to 1.45 fo visually mimic iOS.
final
useMagnifier → bool: final

createElement() → StatefulElement: Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<StatefulWidget>: Creates the mutable state for this widget at a given location in the tree.
override
debugDescribeChildren() → List<DiagnosticsNode>: Returns a list of DiagnosticsNode objects describing this node's children.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void: Add additional properties associated with the node.
inherited
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent 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, int wrapWidth = 65}) → 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