PrependLoadStateBuilder<PageKey, Value> class

A widget that builds a custom UI at the start of the list (prepend) based on the DataSource's loading state.

It provides hasMore and isLoading states to the builder, allowing you to:

  • Show a button only when hasMore is true.
  • Disable the button when isLoading is true.

Example:

PrependLoadStateBuilder(
  dataSource: dataSource,
  builder: (context, hasMore, isLoading) {
    // If there is no more data, show nothing.
    if (!hasMore) {
      return const SizedBox.shrink();
    }

    // Show a manual trigger button.
    // Disable it while loading to prevent double-tapping.
    return FilledButton(
      onPressed: isLoading ? null : () => dataSource.prepend(),
      child: const Text('Load Previous'),
    );
  },
)
Inheritance

Constructors

PrependLoadStateBuilder({Key? key, required DataSource<PageKey, Value> dataSource, required Widget builder(BuildContext context, bool hasMore, bool isLoading)})
Creates a PrependLoadStateBuilder.
const

Properties

builder Widget Function(BuildContext context, bool hasMore, bool isLoading)
A builder function that constructs the widget based on the current state.
final
dataSource DataSource<PageKey, Value>
The DataSource to listen to for paging state changes.
final
hashCode int
The hash code for this object.
no setterinherited
key Key?
Controls how one widget replaces another widget in the tree.
finalinherited
runtimeType Type
A representation of the runtime type of the object.
no setterinherited

Methods

build(BuildContext context) Widget
Describes the part of the user interface represented by this widget.
override
createElement() StatelessElement
Creates a StatelessElement to manage this widget's location in the tree.
inherited
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