'Widget?' can't be assigned to the parameter type 'Widget'

Question

when i assign consumer child:ch that time error shown this:- The argument type 'Widget?' can't be assigned to the parameter type 'Widget'

The code is :

...
Consumer<Cart>(
            builder: (_, cart, ch) => Badge(
                child: ch,
                value: cart.iteamCount.toString(),
                color: Theme.of(context).accentColor),
            child: IconButton(
              icon: Icon(
                Icons.shopping_cart,
              ),
              onPressed: () {},
            ),
          ),
...

Answer 1

It happens because ch is a Widget which is nullable i.e it's defined as Widget?.

So to avoid this , one work around is add not null operator !

Change

child: ch

to

child: ch!