inheritFrom<T extends InheritedModel<Object>> method

T inheritFrom <T extends InheritedModel<Object>>(BuildContext context, { Object aspect })

Makes context dependent on the specified aspect of an InheritedModel of type T.

When the given aspect of the model changes, the context will be rebuilt. The updateShouldNotifyDependent method must determine if a change in the model widget corresponds to an aspect value.

The dependencies created by this method target all InheritedModel ancestors of type T up to and including the first one for which isSupportedAspect returns true.

If aspect is null this method is the same as context.inheritFromWidgetOfExactType(T).

Implementation 

static T inheritFrom<T extends InheritedModel<Object>>(BuildContext context, { Object aspect }) {
  if (aspect == null)
    return context.inheritFromWidgetOfExactType(T);

  // Create a dependency on all of the type T ancestor models up until
  // a model is found for which isSupportedAspect(aspect) is true.
  final List<InheritedElement> models = _findModels<T>(context, aspect).toList();
  final InheritedElement lastModel = models.last;
  for (InheritedElement model in models) {
    final T value = context.inheritFromElement(model, aspect: aspect);
    if (model == lastModel)
      return value;
  }

  assert(false);
  return null;
}