FSelectMenuTile<T>.builder constructor

FSelectMenuTile<T>.builder({ required Widget title, required FSelectTile<T>? menuBuilder(BuildContext, int), int? count, FSelectMenuTileController<T>? selectController, FPopoverController? popoverController, ScrollController? scrollController, FSelectMenuTileStyle style(FSelectMenuTileStyle)?, double? cacheExtent, double maxHeight = double.infinity, DragStartBehavior dragStartBehavior = DragStartBehavior.start, ScrollPhysics physics = const ClampingScrollPhysics(), FItemDivider divider = FItemDivider.full, AlignmentGeometry menuAnchor = Alignment.topRight, AlignmentGeometry tileAnchor = Alignment.bottomRight, FPortalSpacing spacing = const FPortalSpacing(4), Offset shift(Size, FPortalChildBox, FPortalBox) = FPortalShift.flip, Offset offset = Offset.zero, FPopoverHideRegion hideRegion = FPopoverHideRegion.excludeChild, VoidCallback? onTapHide, bool autoHide = true, Widget? label, Widget? description, bool autofocus = false, FocusScopeNode? focusNode, ValueChanged<bool>? onFocusChange, TraversalEdgeBehavior? traversalEdgeBehavior, String? barrierSemanticsLabel, bool barrierSemanticsDismissible = true, String? semanticsLabel, Widget? prefix, Widget? subtitle, ValueWidgetBuilder<Set<T>> detailsBuilder = _builder, Widget? details, Widget? suffix, Map<ShortcutActivator, Intent>? shortcuts, Map<Type, Action<Intent>>? actions, ValueChanged<Set<T>>? onChange, ValueChanged<(T, bool)>? onSelect, Widget errorBuilder(BuildContext, String) = FFormFieldProperties.defaultErrorBuilder, T? initialValue, FormFieldSetter<Set<T>>? onSaved, FormFieldValidator<Set<T>>? validator, String? forceErrorText, bool enabled = true, AutovalidateMode? autovalidateMode, String? restorationId, Key? key, })

Creates a FSelectMenuTile that lazily builds the menu.

The menuBuilder is called for each tile that should be built. The current level's FInheritedItemData is not visible to menuBuilder.

• It may return null to signify the end of the group.
• It may be called more than once for the same index.
• It will be called only for indices <= count if count is given.

The count is the number of tiles to build. If null, menuBuilder will be called until it returns null.

Contract

Throws AssertionError if both selectController and initialValue are provided.

Warning

May result in an infinite loop or run out of memory if:

• Placed in a parent widget that does not constrain its size, i.e., Column.
• count is null and menuBuilder always provides a zero-size widget, i.e., SizedBox(). If possible, provide tiles with non-zero size, return null from the builder, or set count to non-null.

Implementation

FSelectMenuTile.builder({
  required this.title,
  required FSelectTile<T>? Function(BuildContext, int) menuBuilder,
  int? count,
  this.selectController,
  this.popoverController,
  this.scrollController,
  this.style,
  this.cacheExtent,
  this.maxHeight = double.infinity,
  this.dragStartBehavior = DragStartBehavior.start,
  this.physics = const ClampingScrollPhysics(),
  this.divider = FItemDivider.full,
  this.menuAnchor = Alignment.topRight,
  this.tileAnchor = Alignment.bottomRight,
  this.spacing = const FPortalSpacing(4),
  this.shift = FPortalShift.flip,
  this.offset = Offset.zero,
  this.hideRegion = FPopoverHideRegion.excludeChild,
  this.onTapHide,
  this.autoHide = true,
  this.label,
  this.description,
  this.autofocus = false,
  this.focusNode,
  this.onFocusChange,
  this.traversalEdgeBehavior,
  this.barrierSemanticsLabel,
  this.barrierSemanticsDismissible = true,
  this.semanticsLabel,
  this.prefix,
  this.subtitle,
  this.detailsBuilder = _builder,
  this.details,
  this.suffix,
  this.shortcuts,
  this.actions,
  this.onChange,
  this.onSelect,
  Widget Function(BuildContext, String) errorBuilder = FFormFieldProperties.defaultErrorBuilder,
  T? initialValue,
  super.onSaved,
  super.validator,
  super.forceErrorText,
  super.enabled = true,
  super.autovalidateMode,
  super.restorationId,
  super.key,
}) : assert(
       selectController == null || initialValue == null,
       'Cannot provide both selectController and initialValue',
     ),
     super(
       initialValue: {?initialValue, ...?selectController?.value},
       errorBuilder: errorBuilder,
       builder: (field) {
         final state = field as _State<T>;
         final data = FInheritedItemData.maybeOf(state.context);
         final inheritedStyle = FTileGroupStyleData.maybeOf(state.context);

         final global = state.context.theme.selectMenuTileStyle;
         final selectMenuTileStyle = style?.call(global);

         final menuStyle = selectMenuTileStyle?.menuStyle ?? global.menuStyle;
         final tileStyle = selectMenuTileStyle?.tileStyle ?? inheritedStyle?.tileStyle ?? global.tileStyle;

         Widget tile = FPopover(
           // A GlobalObjectKey is used to work around Flutter not recognizing how widgets move inside the widget tree.
           //
           // OverlayPortalControllers are tied to a single _OverlayPortalState, and conditional rebuilds introduced
           // by FLabel and its internals can cause a new parent to be inserted above FPopover. This leads to the
           // entire widget subtree being rebuilt and losing their states. Consequently, the controller is assigned
           // another _OverlayPortalState, causing an assertion to be thrown.
           //
           // See https://stackoverflow.com/a/59410824/4189771
           key: GlobalObjectKey(state._controller._popover),
           controller: state._controller._popover,
           style: menuStyle,
           constraints: FPortalConstraints(maxWidth: menuStyle.maxWidth),
           popoverAnchor: menuAnchor,
           childAnchor: tileAnchor,
           spacing: spacing,
           shift: shift,
           offset: offset,
           hideRegion: hideRegion,
           onTapHide: onTapHide,
           autofocus: autofocus,
           focusNode: focusNode,
           onFocusChange: onFocusChange,
           traversalEdgeBehavior: traversalEdgeBehavior,
           barrierSemanticsLabel: barrierSemanticsLabel,
           barrierSemanticsDismissible: barrierSemanticsDismissible,
           popoverBuilder: (_, _) => FSelectTileGroup<T>.builder(
             selectController: state._controller,
             scrollController: scrollController,
             cacheExtent: cacheExtent,
             maxHeight: maxHeight,
             dragStartBehavior: dragStartBehavior,
             physics: physics,
             style: menuStyle.tileGroupStyle,
             semanticsLabel: semanticsLabel,
             divider: divider,
             tileBuilder: menuBuilder,
             count: count,
           ),
           child: FTile(
             style: tileStyle,
             prefix: prefix,
             enabled: enabled,
             title: title,
             subtitle: subtitle,
             details: ValueListenableBuilder(
               valueListenable: state._controller.delegate,
               builder: detailsBuilder,
               child: details,
             ),
             suffix: suffix ?? const Icon(FIcons.chevronsUpDown),
             shortcuts: shortcuts,
             actions: actions,
             onPress: state._controller._popover.toggle,
           ),
         );

         if (data == null && (label != null || description != null || state.errorText != null)) {
           final states = {if (!enabled) WidgetState.disabled, if (state.errorText != null) WidgetState.error};
           final error = state.errorText == null ? null : errorBuilder(state.context, state.errorText!);
           tile = FLabel(
             axis: Axis.vertical,
             style: global,
             states: states,
             label: label,
             description: description,
             error: error,
             child: tile,
           );
         }

         return tile;
       },
     );