Inkwell not showing ripple when used with Container decoration

Update in 2019:

You should use Ink widget inside Material, instead of Container.
It takes decoration parameter as well:

Material(
      child: Ink(
        decoration: BoxDecoration(
          // ...
        ),
        child: InkWell(
          onTap: () {},
          child: child, // other widget
        ),
      ),
);