解决flutter showDialog下拉框,复选框等无法及时响应的问题

使用StatefulBuilder

  _showDialogr() {
    showDialog(
      context: context,
      builder: (BuildContext ctx) {
        return StatefulBuilder(
          builder: (BuildContext context, StateSetter setState) {
            return Scaffold(
              body: Column(
                children: <Widget>[
                  Container(
                    height: 400,
                    padding: EdgeInsets.fromLTRB(8, 0, 8, 8),
                    decoration: BoxDecoration(
                      borderRadius: BorderRadius.circular(20),
                      color: Colors.white,
                    ),
                    child: Column(
                      mainAxisSize: MainAxisSize.min,
                      children: <Widget>[
                        SizedBox(
                          height: 15,
                        ),
                        Expanded(
                          flex: 6,
                          child: Column(
                            mainAxisSize: MainAxisSize.min,
                            children: <Widget>[
                              Row(
                                children: [
                                  Expanded(
                                    flex: 8,
                                    child: DropdownButton<String>(
                                      items: getList(),
                                      hint: Text('请选择'),
                                      value: Id,
                                      onChanged: (String? str) {
                                        setState(() {
                                         Id = str;
                                        });
                                      },
                                      elevation: 24,
                                      style: TextStyle(
                                        color: Colors.black,
                                        fontSize: 16,
                                      ),
                                    ),
                                  ),
                                ],
                              ),
                            ],
                          ),
                        ),
                      ],
                    ),
                  ),
                ],
              ),
            );
          },
        );
      },
    );
  }