SDropdown class

A fully custom dropdown widget built from scratch for String items with complete control over dimensions and behavior. This widget provides a native Flutter dropdown implementation with:

  • Full control over widget width and height
  • Simplified API focused on String items only
  • Custom overlay system using CompositedTransformTarget/Follower
  • Minimal external dependencies: uses a small set of helper packages for responsive sizing, indexed lists, and animation helpers
  • Comprehensive styling through SDropdownDecoration
  • Support for item-specific text styles
  • Scroll controller support for precise positioning
  • Native Flutter performance and behavior
  • Smooth roll-up/down animations with fade effects
Inheritance
Available extensions

Constructors

SDropdown({Key? key, required List<String> items, List<String> customItemsNamesDisplayed = const [], double? width, double? height, double? overlayHeight, double? overlayWidth, double? scale, String? selectedItem, String? initialItem, String? hintText, dynamic onChanged(String?)?, TextStyle? itemTextStyle, TextStyle? headerTextStyle, TextStyle? hintTextStyle, Map<String, TextStyle>? itemSpecificStyles, Color? closedFillColor, Color? expandedFillColor, Border? closedBorder, Border? expandedBorder, BorderRadius? closedBorderRadius, BorderRadius? expandedBorderRadius, EdgeInsets? closedHeaderPadding, EdgeInsets? expandedHeaderPadding, EdgeInsets? itemsListPadding, EdgeInsets? listItemPadding, ScrollController? itemsScrollController, bool excludeSelected = true, bool canCloseOutsideBounds = true, bool enabled = true, AlignmentGeometry? alignment, int maxLines = 1, Widget? suffixIcon, Widget? clearButtonIcon, bool showClearButton = true, bool clearButtonRestoresInitialSelection = false, Widget? prefixIcon, String? validator(String?)?, bool validateOnChange = true, SDropdownDecoration? decoration, Color? headerExpandedColor, String? selectedItemText, SDropdownController? controller, Object? tapRegionGroupId, int? autoScrollMaxFrameDelay, int? autoScrollEndOfFrameDelay, bool useKeyboardNavigation = true, FocusNode? focusNode, bool requestFocusOnInit = false})
const

Properties

alignment → AlignmentGeometry?
Alignment of the widget within its parent
final
autoScrollEndOfFrameDelay → int?
final
autoScrollMaxFrameDelay → int?
final
canCloseOutsideBounds → bool
Whether the dropdown can be closed by tapping outside
final
clearButtonIcon → Widget?
Optional clear button shown in the suffix area when an item is selected.
final
clearButtonRestoresInitialSelection → bool
Whether the clear button restores the initial selection instead of clearing to the hint state.
final
closedBorder → Border?
Border for the closed dropdown
final
closedBorderRadius → BorderRadius?
Border radius for the closed dropdown
final
closedFillColor → Color?
Background color of the closed dropdown
final
closedHeaderPadding → EdgeInsets?
Padding for the closed header
final
controller → SDropdownController?
Controller used to manage the dropdown programmatically
final
customItemsNamesDisplayed → List<String>
The list of string items to display
final
decoration → SDropdownDecoration?
Custom decoration for the dropdown
final
enabled → bool
Whether the dropdown is enabled
final
excludeSelected → bool
Whether to exclude the selected item from the dropdown list
final
expandedBorder → Border?
Border for the expanded dropdown overlay
final
expandedBorderRadius → BorderRadius?
Border radius for the expanded dropdown overlay
final
expandedFillColor → Color?
Background color of the expanded dropdown overlay
final
expandedHeaderPadding → EdgeInsets?
Padding for the expanded header
final
focusNode → FocusNode?
Optional FocusNode for keyboard navigation. If not provided and useKeyboardNavigation is true, an internal FocusNode will be created.
final
hashCode → int
The hash code for this object.
no setterinherited
headerExpandedColor → Color?
Color for the header when expanded
final
headerTextStyle → TextStyle?
Text style for the header (selected item)
final
height → double?
The height of the dropdown widget
final
hintText → String?
Hint text to display when no item is selected
final
hintTextStyle → TextStyle?
Text style for the hint text
final
initialItem → String?
Initial selected item (if no controller is used)
final
items → List<String>
The list of string items to display
final
itemsListPadding → EdgeInsets?
Padding for the items list
final
itemSpecificStyles → Map<String, TextStyle>?
Map of item-specific text styles
final
itemsScrollController → ScrollController?
Scroll controller for the items list (wrapped internally by an IndexedScrollController)
final
itemTextStyle → TextStyle?
Text style for dropdown items
final
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
listItemPadding → EdgeInsets?
Padding for each list item
final
maxLines → int
Maximum lines for text display
final
onChanged → dynamic Function(String?)?
Callback when selection changes
final
overlayHeight → double?
The height of the dropdown overlay when expanded
final
overlayWidth → double?
The width of the dropdown overlay when expanded
final
prefixIcon → Widget?
Prefix icon for the closed dropdown
final
requestFocusOnInit → bool
Whether to request focus on initialization when useKeyboardNavigation is true
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
scale → double?
Scale factor for the entire widget
final
selectedItem → String?
The currently selected item
final
selectedItemText → String?
The currently selected item
final
showClearButton → bool
Whether to show a clear button when the dropdown has a selection.
final
suffixIcon → Widget?
Suffix icon for the closed dropdown
final
tapRegionGroupId → Object?
Optional tap-region group ID for the dropdown overlay.
final
useKeyboardNavigation → bool
Whether to enable keyboard navigation (arrow keys, enter, escape)
final
validateOnChange → bool
Whether to validate on change
final
validator → String? Function(String?)?
Validator function
final
width → double?
The width of the dropdown widget
final

Methods

addMaterialWidget() → Material

Available on Widget, provided by the GenericExtensions extension

addTooltipWidget(String toolTip) → Tooltip

Available on Widget, provided by the GenericExtensions extension

animate({Key? key, List<Effect>? effects, AnimateCallback? onInit, AnimateCallback? onPlay, AnimateCallback? onComplete, bool? autoPlay, Duration? delay, AnimationController? controller, Adapter? adapter, double? target, double? value}) → Animate

Available on Widget, provided by the AnimateWidgetExtensions extension

Wraps the target Widget in an Animate instance, and returns the instance for chaining calls. Ex. myWidget.animate() is equivalent to Animate(child: myWidget).
borderRadius([BorderRadiusGeometry? borderRadius]) → Widget

Available on Widget, provided by the GenericExtensions extension

boxDecoration([BoxDecoration? boxDecoration]) → Widget

Available on Widget, provided by the GenericExtensions extension

colorFilter([ColorFilter? colorFilter]) → Widget

Available on Widget, provided by the GenericExtensions extension

set parent widget in center
copyWith({double? width, double? height, double? overlayHeight, double? overlayWidth, double? scale, List<String>? items, String? selectedItem, String? initialItem, String? hintText, dynamic onChanged(String?)?, TextStyle? itemTextStyle, TextStyle? headerTextStyle, TextStyle? hintTextStyle, Map<String, TextStyle>? itemSpecificStyles, Color? closedFillColor, Color? expandedFillColor, Border? closedBorder, Border? expandedBorder, BorderRadius? closedBorderRadius, BorderRadius? expandedBorderRadius, EdgeInsets? closedHeaderPadding, EdgeInsets? expandedHeaderPadding, EdgeInsets? itemsListPadding, EdgeInsets? listItemPadding, ScrollController? itemsScrollController, bool? excludeSelected, bool? canCloseOutsideBounds, bool? enabled, AlignmentGeometry? alignment, int? maxLines, Widget? suffixIcon, Widget? clearButtonIcon, bool? showClearButton, bool? clearButtonRestoresInitialSelection, Widget? prefixIcon, String? validator(String?)?, bool? validateOnChange, SDropdownDecoration? decoration, SDropdownController? controller, Object? tapRegionGroupId, bool? useKeyboardNavigation, FocusNode? focusNode, bool? requestFocusOnInit}) → SDropdown

Available on SDropdown, provided by the SDropdownExtension extension

Creates a copy of this dropdown with modified properties
createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<SDropdown>
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

Operators

operator ==(Object other) → bool
The equality operator.
inherited