flutter sqflite how to receive a 'todo' object to display the values?

Question

I am using sqflite to do inserts from OnCreate. Those inserts work fine, and i can visualice the items in a ListView:

But when I touch the item from that list, I get this error:

this is the code of my list that works okay, and where i send the object 'todo' to another screen:

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
          //...
      ),

here i make conection bd, snapshot, and sending object 'todo':

      body: FutureBuilder<List<todo>>(
        future: _todo,
        builder: (BuildContext context, AsyncSnapshot<List<todo>> snapshot) {
          if (snapshot.connectionState == ConnectionState.waiting) {
            return const Center(
              child: const CircularProgressIndicator(),
            );
          } else if (snapshot.hasError) {
            return Text('Error: ${snapshot.error}');
          } else {
            var items = snapshot.data ?? <todo>[];

            return Container(
              margin: EdgeInsets.symmetric(
                horizontal: 5.0,
                vertical: 5.0,
              ),
              decoration: BoxDecoration(
                borderRadius: BorderRadius.circular(12),
              ),
              child: ListView.builder(
                itemCount: items.length,
                itemBuilder: (BuildContext context, int index) {
                  return GestureDetector(
                    onTap: () {
                      Navigator.push(
                        context,
                        MaterialPageRoute(
                          //HERE I SEND THE OBJECT 'todo' IN INDEX SELECTEDTO DETAILSCREEN
                          builder: (context) => DetailScreen(td: items[index]),
                        ),
                      );
                    },
                    child: Card(
                        child: ListTile(
                      leading: SizedBox(
                        height: 100.0,
                        width: 80.0,
                        child: Image.network(items[index].imgcourse),
                      ),

                      shape: RoundedRectangleBorder(
                        borderRadius: BorderRadius.circular(15),
                      ),

                      title: Text(
                        items[index].title,
                        style: TextStyle(
                          fontSize: 20,
                          color: Colors.blueAccent,
                        ),
                      ),

                    )),
                  );

                },
              ),
            );
          }
        },
      ),
   );
  }

this is the DetailScreen where i receive the 'todo' object:

class DetailScreen extends StatelessWidget {
  todo td;
  DetailScreen({required this.td});

  late DatabaseHandler handler;
  late Future<List<todo>> _todo;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.grey[850],
      appBar: AppBar(
        title: Text(
          td.title,
          style: TextStyle(
            fontSize: 16.0, /*fontWeight: FontWeight.bold*/
          ),
        ),

        centerTitle: true,
      ),

      body: Container(
              padding: EdgeInsets.symmetric(
                horizontal: 8,
              ),
              color: Colors.grey[800],
              child: SingleChildScrollView(
                child: Column(
                  children: [

                    //NAME ITEM
                    Container(
                      alignment: Alignment.centerLeft,
                      padding: EdgeInsets.symmetric(vertical: 3, horizontal: 5),

                      child: RichText(
                        text: new TextSpan(
                          style: new TextStyle(
                            fontSize: 15.0,
                            color: Colors.white,
                          ),
                          children: <TextSpan>[
                            new TextSpan(
                                text: 'Nombre: ',
                                style: new TextStyle(
                                    fontWeight: FontWeight.bold,
                                    color: Colors.blueAccent)),
                            new TextSpan(text: td.title),
                          ],
                        ),
                      ),
                    ),
                    SizedBox(
                      height: 10,
                    ),


                    // DESCRIPTION TIEM
                    Container(
                      alignment: Alignment.centerLeft,
                      padding: EdgeInsets.symmetric(horizontal: 5.0),
                      child: RichText(
                        text: new TextSpan(
                          style: new TextStyle(
                            fontSize: 15.0,
                            color: Colors.white,
                          ),
                          children: <TextSpan>[
                            new TextSpan(
                                text: 'Detalles: ',
                                style: new TextStyle(
                                    fontWeight: FontWeight.bold,
                                    color: Colors.blueAccent)),
                            new TextSpan(text: td.description),
                          ],
                        ),
                      ),
                    ),

                  ],
                ),
              ),
            );
      ),
      );
  }
}

this is my 'todo' class:

I would like to know how to receive the object and read items inside, im new in sqflite and flutter.