Observer class

A StatelessObserverWidget that delegate its build method to builder.

See also:

• Builder, which is the same thing but for StatelessWidget instead.

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• StatelessObserverWidget
• Observer

Implemented types

• Builder

Constructors

Observer({Key? key, required WidgetBuilder builder, String? name, bool? warnWhenNoObservables})

Properties

builder → WidgetBuilder

Called to obtain the child widget.

final

debugConstructingStackFrame → String?

The stack frame pointing to the source that constructed this instance.

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

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

warnWhenNoObservables → bool?

Whether to warn when there is no observables in the builder function null means true

final, inherited

Methods

build(BuildContext context) → Widget

Describes the part of the user interface represented by this widget.

override

createElement() → StatelessObserverElement

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

inherited

createReaction(dynamic onInvalidate(), {dynamic onError(Object, Reaction)?}) → Reaction

A convenience method used for testing.

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

getContext() → ReactiveContext

The context within which its reaction should be run. It is the mainContext in most cases.

inherited

getName() → String

An identifiable name that can be overriden for debugging.

override

log(String msg) → void

Convenience method to output console messages as debugging output. Logging usually happens when some internal error needs to be surfaced to the user.

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

Static Methods

debugFindConstructingStackFrame([StackTrace? stackTrace]) → String?

Finds the first non-constructor frame in the stack trace.