LayoutBuilder(
    builder: (BuildContext context, BoxConstraints viewportConstrains) {
      return SingleChildScrollView(
        child: Column(
          children: <Widget>[
            //子Widget
          ],
        ),
      );
    },
)

LayoutBuilder(
    builder: (BuildContext context, BoxConstraints viewportConstrains) {
      return SingleChildScrollView(
        child: ConstrainedBox(
          constraints: BoxConstraints(
            minHeight: viewportConstrains.maxHeight,
          ),
          child: Column(
            children: <Widget>[
                //子Widget
            ],
          ),
        ),
      );
    },
)

Scrollbar(
    child: SingleChildScrollView(
      child: Column(
        children: <Widget>[
            //子Widget
        ],
      ),
    ), 
)

SingleChildScrollView(
  child: Column(
    children: <Widget>[
        //子Widget
    ],
  ),
)