"Android Fill Viewport" style of content for Flutter, where even when the keyboard appears the content flows behind.

## fill_viewport.dart

class SomeWidgetState extends State<SomeWidget> {
	@override
	Widget build(BuildContext context) {
		return new Scaffold(body: new LayoutBuilder(builder: _buildContent));
	}

	Widget _buildContent(BuildContext context, BoxConstraints constraints) {
		if (constraints.hasBoundedHeight) {
			constraints = constraints.copyWith(maxHeight: constraints.maxHeight +
				MediaQuery.of(context).viewInsets.vertical);
		}
		return new SingleChildScrollView(
			child: new ConstrainedBox(
				constraints: constraints,
				child: new Column(
					children: <Widget>[
						/* ... */
					],
				),
			),
		);
	}
}