Flutter 如何在用Ffltter成功登录后重定向下一页

我用Ffltter创建了一个简单的登录应用程序.后端是简单的JWT.登录成功后，不能重定向到其他页面请帮助 这是登录页面代码

            //login buttom
            SizedBox(
              width: 360,
              child: Padding(
                padding: const EdgeInsets.only(top: 48.0),
                child: ElevatedButton(
                  onPressed: () {
                    authController.loginUser();
                  },
                  style: ElevatedButton.styleFrom(
                      backgroundColor: const Color.fromARGB(255, 40, 41, 131),
                      padding: const EdgeInsets.only(
                        top: 16,
                        bottom: 16,
                      )),
                  child: const Text(
                    'ログイン ',
                    style: TextStyle(
                        color: Colors.white,
                        fontSize: 16,
                        fontWeight: FontWeight.w700),
                  ),
                ),
              ),
            ), //end login buttom
            const SizedBox(
              height: 60,
            ),
          ],
        ),
      ),
    );
  }
}

这是身份验证控制器代码

class AuthController {
  TextEditingController emailController = TextEditingController();
  TextEditingController passwordController = TextEditingController();
  Future loginUser() async {
    const url = 'http://127.0.0.1:8000/api/v1/login/';

    var response = await http.post(Uri.parse(url),
        headers: {
          "content-type": "application/json",
          "accept": "application/json",
          "access": "Access-Control-Allow-Origin: *",
          "allow": "POST, OPTIONS",
        },
        body: jsonEncode({
          "email": emailController.text,
          "password": passwordController.text,
        }));
    if (response.statusCode == 200) {
      var loginArr = json.decode(response.body);
      print('Home');
      Navigator.push(context, MaterialPageRoute(builder: (context) => Nav()));
      // save this token in shared prefrences and make user logged in and navigate

      print(loginArr['token']);
    } else {}
  }
}

我try 修复此错误请帮助me.how成功登录后导航到其他页面