QueryBuilder<T> class

A widget that executes an async operation and builds UI based on its state.

QueryBuilder automatically manages the query lifecycle, subscribing when mounted and unsubscribing when disposed. It handles loading, error, and success states, making async operations simple to use in Flutter widgets.

The query is shared across all widgets with the same queryKey, so multiple QueryBuilder widgets with identical keys will share state and only execute the async operation once.

Example:

QueryBuilder<List<User>>(
  queryKey: 'users',
  queryFn: () => api.fetchUsers(),
  builder: (context, state) {
    if (state.isLoading) return CircularProgressIndicator();
    if (state.hasError) return Text('Error: ${state.error}');
    if (state.hasData) return UserList(users: state.data!);
    return SizedBox();
  },
)

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatefulWidget
• QueryBuilder

Constructors

QueryBuilder({required QueryKey queryKey, required Widget builder(BuildContext context, QueryState<T> state), Future<T> queryFn()?, Future<T> queryFnWithToken(CancellationToken token)?, QueryOptions? options, QueryKey? dependsOn, Key? key})

Creates a QueryBuilder for the given queryKey.

const

Properties

builder → Widget Function(BuildContext context, QueryState<T> state)

Builds the widget tree based on the current query state.

final

dependsOn → QueryKey?

The parent query key that this query depends on.

final

hashCode → int

The hash code for this object.

no setter, inherited

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

options → QueryOptions?

Optional configuration for the query.

final

queryFn → Future<T> Function()?

The async function to execute.

final

queryFnWithToken → Future<T> Function(CancellationToken token)?

The async function to execute with cancellation support.

final

queryKey → QueryKey

Unique identifier for this query.

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

createElement() → StatefulElement

Creates a StatefulElement to manage this widget's location in the tree.

inherited

createState() → State<QueryBuilder<T>>

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