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 {
  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(
    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.

See also:



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


bundle AssetBundle
The bundle to use as a default.
child Widget
The widget below this widget in the tree.
final, inherited
hashCode int
The hash code for this object.
@nonVirtual, read-only, 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.
read-only, inherited


createElement() InheritedElement
Inflates this configuration to a concrete instance.
debugDescribeChildren() List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
@protected, inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
toString({DiagnosticLevel minLevel =}) String
A string representation of this object.
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) String
Returns a string representation of this node and its descendants.
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) String
Returns a one-line detailed description of the object.
toStringShort() String
A short, textual description of this widget.
updateShouldNotify(covariant DefaultAssetBundle oldWidget) bool
Whether the framework should notify widgets that inherit from this widget.


operator ==(Object other) bool
The equality operator.
@nonVirtual, inherited

Static Methods

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