构建 RegisterScreen() 时抛出了以下 _TypeError：类型“String”不是“index”的“int”类型的子类型

Question

String? _selectedCity;
List cities = ['Select City'];

  @override
  void initState() {
    super.initState();
    _secureText = true;
    _getCities();
  }

  Future _getCities() async {
    var url = "baseurl/api/v1/cities";
    try {
      var response = await http.get(Uri.parse(url));
      if (response.statusCode == 200) {
        var data = json.decode(response.body);
        setState(() {
          cities = data;
        });
      }
      print(cities);
    } catch (e) {
      // ignore: avoid_print
      print("Error: $e");
    }
  }

DropdownButton(
    hint
    : const Text("Select City"), value
    : _selectedCity, items
    : cities
          .map((category) {
              return DropdownMenuItem(value
                  : category['name'], child
                  : Text(category['name']), );
          })
          .toList(),
    onChanged
    : (value) { setState(() { _selectedCity = value as String ? ; }); })

there is problem in my Dropdown Button

Value from dropdown were seen before but after update of 2023/1/25, i am facing error "type 'String' is not a subtype of type 'int' of 'index'"

Answer 1

Replace this code in your own code. must be correct.

DropdownButton(
    hint: const Text("Select City"), 
    value: _selectedCity, 
    items: cities
          .map((category) {
              return DropdownMenuItem(
                  value: category['name'], 
                  child: Text(category['name'])
              );
          })
          .toList(),
    onChanged: (value) { 
        setState(() { 
            _selectedCity = value; 
        }); 
    })