DefaultAssetBundle class Null safety

A widget that determines the default asset bundle for its descendants.

For example, used by Image to determine which bundle to use for AssetImages if no bundle is specified explicitly.

This can be used in tests to override what the current asset bundle is, thus allowing specific resources to be injected into the widget under test.

For example, a test could create a test asset bundle like this:

class TestAssetBundle extends CachingAssetBundle {
  @override
  Future<ByteData> load(String key) async {
    if (key == 'resources/test') {
      return ByteData.view(Uint8List.fromList(utf8.encode('Hello World!')).buffer);
    }
    return ByteData(0);
  }
}

...then wrap the widget under test with a DefaultAssetBundle using this bundle implementation:

await tester.pumpWidget(
  MaterialApp(
    home: DefaultAssetBundle(
      bundle: TestAssetBundle(),
      child: const TestWidget(),
    ),
  ),
);

Assuming that TestWidget uses DefaultAssetBundle.of to obtain its AssetBundle, it will now see the TestAssetBundle's "Hello World!" data when requesting the "resources/test" asset.

Constructors

DefaultAssetBundle({Key? key, required AssetBundle bundle, required Widget child}): Creates a widget that determines the default asset bundle for its descendants.
const

Properties

bundle → AssetBundle: The bundle to use as a default.
final
child → Widget: The widget below this widget in the tree.
finalinherited
hashCode → int: The hash code for this object.
nonVirtual">@nonVirtualread-onlyinherited
key → Key?: Controls how one widget replaces another widget in the tree.
finalinherited
runtimeType → Type: A representation of the runtime type of the object.
read-onlyinherited

Methods

createElement() → InheritedElement: Inflates this configuration to a concrete instance.
inherited
debugDescribeChildren() → List<DiagnosticsNode>: Returns a list of DiagnosticsNode objects describing this node's children.
protected">@protectedinherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void: Add additional properties associated with the node.
inherited
noSuchMethod(Invocation invocation) → dynamic: Invoked when a non-existent 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}) → 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
updateShouldNotify(covariant DefaultAssetBundle oldWidget) → bool: Whether the framework should notify widgets that inherit from this widget.
override

Operators

operator ==(Object other) → bool: The equality operator.
nonVirtual">@nonVirtualinherited

Static Methods

of(BuildContext context) → AssetBundle: The bundle from the closest instance of this class that encloses the given context.

Flutter
widgets
DefaultAssetBundle class