Adding Shadows at the bottom of a container in flutter?

You can reuse the first container that you have in your Stack, the container has a property called decoration and it accept a widget of kind BoxDecoration, as you can see in this link: BoxDecorationInside this widget you can use the boxShadow property to give to your container a custom shadow, try the next code:

new Container(      height: margin_100dp,      decoration: BoxDecoration(          boxShadow: <BoxShadow>[            BoxShadow(                color: Colors.black54,                blurRadius: 15.0,                offset: Offset(0.0, 0.75)            )          ],        color: colorPrimary      ),    ),

Or you can wrap your Container widget with a Material widget which contains an elevation property to give the shadowy effects.

Container(          child: Row(            mainAxisAlignment: MainAxisAlignment.center,            children: <Widget>[              Material(                elevation: 15.0,                child: Container(                  height: 100,                  width: 100,                  color: Colors.blue,                  child: Center(child: Text("Material",style: TextStyle(color: Colors.white),)),                ),              ),              SizedBox(width: 100,),              Container(                height: 100,                width: 100,                decoration: BoxDecoration(                    boxShadow: <BoxShadow>[                      BoxShadow(                          color: Colors.black54,                          blurRadius: 15.0,                          offset: Offset(0.0, 0.75)                      )                    ],                    color: Colors.blue                ),                child: Center(child: Text('Box Shadow',style: TextStyle(color: Colors.white))),              ),            ],          ),        ),

Image:

Difference between two widgets is shown above. Hope this helps!!!

Yes, BoxShadow can solve the problem but instead of manually adding the list of BoxShadow, there is a handy map in flutter call kElevationToShadow which map elevation keys to pre-defined list of BoxShadow. It is also defined based on the material design elevation.

Container(  height: 60.0,  decoration: BoxDecoration(    boxShadow: kElevationToShadow[4],    color: Theme.of(context).bottomAppBarColor,  ),  child: ...);