Solution: Navigation and Routing

IconButton(
    onPressed: () {
    // TODO-1: Return data from screen below
    // solution
        Navigator.pop(context, shopItem.itemName);
    },
    icon: const Icon(
        Icons.arrow_back,
        size: 32,
    ),
),
GestureDetector(
    // TODO-2: Display data received
    // solution
    onTap: () async{
        var data = await Navigator.pushNamed(context, itemDetailRoute,arguments: shopList[index]);
        ScaffoldMessenger.of(context)
            ..removeCurrentSnackBar()
            ..showSnackBar(SnackBar(content: Text('$data')));
    },
    child: ItemCard(
        shopItem: shopList[index],
    ),
),   
ElevatedButton(
    onPressed: () {
    // TODO-3: Clear routes to first screen
    // solution
        Navigator.popUntil(context, (route)=> route.isFirst);
    },
...
)