「flutter firebase provider」firebaseでgetしたデータを表示できない問題について。

問題点

以下のようなプログラムをflutter firebase provderを使って作っています。
⓵でCardをタップしたらタップされたドキュメントIDを使い⓶でデータを取得し③で表示したいのですが、コンソールには出力できるのですが、③のページに表示できません。
ご教授よろしくお願いいたします。

①

dart
1       body: Consumer<TeaProvider>(builder: (context, model, child) {
2          final todoList = model.todoList;
3          return ListView(
4            children: todoList
5                .map(
6                  (todo) => Card(
7                    margin: const EdgeInsets.only(left:20,right:20,top:5,bottom:5),
8                    elevation: 3,
9                    child: InkWell(
10                      onTap: ()async{
11                        await deleteBook(context , model , todo);
12                        Navigator.push(
13                            context,
14                            MaterialPageRoute(builder: (context) => ViewPage()));
15                      },
16                      child: Container(
17                          height: MediaQuery.of(context).size.height * 0.15,
18                          child:  Row(
19                            mainAxisAlignment: MainAxisAlignment.start,
20                            children: [
21                              Column(
22                                mainAxisAlignment: MainAxisAlignment.spaceAround,
23                                crossAxisAlignment: CrossAxisAlignment.center,
24                                children: [
25                                  Padding(
26                                    padding: const EdgeInsets.only(right:10.0,left:10.0),
27                                    child: Container(
28                                      width: 50,
29                                      height: 50,
30                                      decoration: BoxDecoration(
31                                          color: Colors.red,
32                                          shape: BoxShape.circle
33                                      ),
34                                    ),
35                                  ),
36                                  Padding(
37                                    padding: const EdgeInsets.only(
38                                        right: 10.0, left: 10.0),
39                                    child: Text(todo.name,
40                                    ),
41                                  ),
42                                ],
43                              ),
44                              Container(
45                                  height: 80,
46                                  child: VerticalDivider(
47                                    color: Colors.black54,
48                                  )
49                              ),
50                              Flexible(
51                                child: Column(
52                                  crossAxisAlignment: CrossAxisAlignment.start,
53                                  mainAxisAlignment: MainAxisAlignment.start,
54                                  children: [
55                                    Padding(
56                                      padding: const EdgeInsets.only(bottom:4.0),
57                                      child: Text(todo.recipe,
58                                        overflow: TextOverflow.ellipsis,
59                                        maxLines: 2,
60                                        style: TextStyle(
61                                            fontWeight: FontWeight.bold,
62                                            fontSize: 17
63                                        ),),
64                                    ),
65                                    Text(todo.title,
66                                      overflow: TextOverflow.ellipsis,
67                                      maxLines: 2,
68                                    ),
69                                    Text( '調理時間：'+todo.time+'min')
70                                  ],
71                                ),
72                              )
73                            ],
74                          )
75                      ),
76                    ),
77
78                  ),
79            ).toList(),
80          );
81        }),

⓶

dart
1※抜粋しています
2class TeaProvider extends ChangeNotifier {
3  Future getTapmodel(Todo todo) async{
4    final snapshoted = await FirebaseFirestore.instance
5        .collection('todoList')
6        .doc(todo.documentID)
7        .get();
8    notifyListeners();
9    viewText = snapshoted['title'];
10    viewTodo = snapshoted['name'];
11    viewItem = snapshoted['recipe'];
12    viewTime = snapshoted['time'];
13    viewName = snapshoted['material'];
14    print(viewText);
15    print(viewTime);
16    print(viewTodo);
17    print(viewName);
18    print(viewItem);
19    notifyListeners();
20  }
21  String viewText;
22  String viewTodo;
23  String viewItem;
24  String viewTime;
25  String viewName;
26
27}

⓷

dart
1class ViewPage extends StatelessWidget {
2
3  @override
4  Widget build(BuildContext context) {
5    return ChangeNotifierProvider<TeaProvider>(
6      create: (_) => TeaProvider(),
7        child: Scaffold(
8            appBar: AppBar(
9              backgroundColor: Colors.green,
10              title: Text('Tea App'),
11              centerTitle: true,
12            ),
13            body: Consumer<TeaProvider>(builder: (context, model, child) {
14              return Container(
15                child: Center(
16                  child: Column(
17                    children: [
18                      Text(model.viewItem??'データなし'),
19                      Text(model.viewName??'データなし'),
20                      Text(model.viewTodo??'データなし'),
21                      Text(model.viewTime??'データなし'),
22                      Text(model.viewText??'データなし'),
23                  ]
24                ),
25                )
26              );
27            },
28            )
29        ),
30    );
31  }
32}
33