FlutterListViewDelegate class
Constructors
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FlutterListViewDelegate(NullableIndexedWidgetBuilder builder, {int? childCount, bool addAutomaticKeepAlives = true, bool addRepaintBoundaries = true, bool addSemanticIndexes = true, SemanticIndexCallback semanticIndexCallback = _kDefaultSemanticIndexCallback, int semanticIndexOffset = 0, FlutterListViewDelegateOnItemKey? onItemKey, bool keepPosition = false, double keepPositionOffset = 0, FlutterListViewDelegateOnItemSticky? onItemSticky, FlutterListViewDelegateOnItemHeight? onItemHeight, double preferItemHeight = 50, FirstItemAlign firstItemAlign = FirstItemAlign.start})
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Creates a delegate that supplies children for slivers using the given
builder callback.
const
Properties
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addAutomaticKeepAlives
→ bool
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Whether to wrap each child in an AutomaticKeepAlive.
final
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addRepaintBoundaries
→ bool
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Whether to wrap each child in a RepaintBoundary.
final
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addSemanticIndexes
→ bool
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Whether to wrap each child in an IndexedSemantics.
final
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builder
→ NullableIndexedWidgetBuilder
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Called to build children for the sliver.
final
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childCount
→ int?
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The total number of children this delegate can provide.
final
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estimatedChildCount
→ int?
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Returns an estimate of the number of children this delegate will build.
no setteroverride
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firstItemAlign
→ FirstItemAlign
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When item is not enough fill one viewport. Where is the items shoule align to
For example: if reverse is false,
When firstItemAlign=FirstItemAlign.start, the item should located on top.
When firstItemAlign=FirstItemAlign.end, the item should located on bottom.
final
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hashCode
→ int
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The hash code for this object.
no setterinherited
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keepPosition
→ bool
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Whem keepPosition is false, If some item insert to header, the render items will scroll down a distance
which is equal the inserted items' height, When the property set to true, The current render item will
keep same position. Notice: it the keepPosition set to true, onItemKey must not be null and each item's must
unique.
When keepPosition is true and scrolloffset>=keepPositionOffset, the keep position will enable
final
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keepPositionOffset
→ double
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final
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onItemHeight
→ FlutterListViewDelegateOnItemHeight?
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If you know the item height, it is better provider the height
It can provide better user expierence
final
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onItemKey
→ FlutterListViewDelegateOnItemKey?
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onItemKey will indicate the item key
The key will used to ref the item's height
If you enable keepPosition, the key will be used to identify inserted items
which is before the current rendered key
final
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onItemSticky
→ FlutterListViewDelegateOnItemSticky?
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Query the item is sticky to header.
final
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preferItemHeight
→ double
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If you didn't provide onItemHeight, the preferItemHeight will be apply to item which is not render.
final
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runtimeType
→ Type
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A representation of the runtime type of the object.
no setterinherited
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semanticIndexCallback
→ SemanticIndexCallback
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A SemanticIndexCallback which is used when addSemanticIndexes is true.
final
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semanticIndexOffset
→ int
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An initial offset to add to the semantic indexes generated by this widget.
final
