inheritFromElement method

Implementation

@override
InheritedWidget inheritFromElement(Element ancestor, { Object aspect }) {
  assert(ancestor != null);
  assert(() {
    final Type targetType = ancestor.widget.runtimeType;
    if (state._debugLifecycleState == _StateLifecycle.created) {
      throw FlutterError(
        'inheritFromWidgetOfExactType($targetType) or inheritFromElement() was called before ${_state.runtimeType}.initState() completed.\n'
        'When an inherited widget changes, for example if the value of Theme.of() changes, '
        'its dependent widgets are rebuilt. If the dependent widget\'s reference to '
        'the inherited widget is in a constructor or an initState() method, '
        'then the rebuilt dependent widget will not reflect the changes in the '
        'inherited widget.\n'
        'Typically references to to inherited widgets should occur in widget build() methods. Alternatively, '
        'initialization based on inherited widgets can be placed in the didChangeDependencies method, which '
        'is called after initState and whenever the dependencies change thereafter.'
      );
    }
    if (state._debugLifecycleState == _StateLifecycle.defunct) {
      throw FlutterError(
        'inheritFromWidgetOfExactType($targetType) or inheritFromElement() was called after dispose(): $this\n'
        'This error happens if you call inheritFromWidgetOfExactType() on the '
        'BuildContext for a widget that no longer appears in the widget tree '
        '(e.g., whose parent widget no longer includes the widget in its '
        'build). This error can occur when code calls '
        'inheritFromWidgetOfExactType() from a timer or an animation callback. '
        'The preferred solution is to cancel the timer or stop listening to the '
        'animation in the dispose() callback. Another solution is to check the '
        '"mounted" property of this object before calling '
        'inheritFromWidgetOfExactType() to ensure the object is still in the '
        'tree.\n'
        'This error might indicate a memory leak if '
        'inheritFromWidgetOfExactType() is being called because another object '
        'is retaining a reference to this State object after it has been '
        'removed from the tree. To avoid memory leaks, consider breaking the '
        'reference to this object during dispose().'
      );
    }
    return true;
  }());
  return super.inheritFromElement(ancestor, aspect: aspect);
}