Nested class

A widget that simplify the writing of deeply nested widget trees.

It relies on the new kind of widget SingleChildWidget, which has two concrete implementations:

• SingleChildStatelessWidget
• SingleChildStatefulWidget

They are both respectively a SingleChildWidget variant of StatelessWidget and StatefulWidget.

The difference between a widget and its single-child variant is that they have a custom build method that takes an extra parameter.

As such, a StatelessWidget would be:

class MyWidget extends StatelessWidget {
  MyWidget({Key key, this.child}): super(key: key);

  final Widget child;

  @override
  Widget build(BuildContext context) {
    return SomethingWidget(child: child);
  }
}

Whereas a SingleChildStatelessWidget would be:

class MyWidget extends SingleChildStatelessWidget {
  MyWidget({Key key, Widget child}): super(key: key, child: child);

  @override
  Widget buildWithChild(BuildContext context, Widget child) {
    return SomethingWidget(child: child);
  }
}

This allows our new MyWidget to be used both with:

MyWidget(
  child: AnotherWidget(),
)

and to be placed inside children of Nested like so:

Nested(
  children: [
    MyWidget(),
    ...
  ],
  child: AnotherWidget(),
)