Flutter Json FormatException

Question

在我的应用程序中，我尝试从共享首选项中检索数据，并将该值传递给提供程序。我怎么会遇到异常呢？

FormatException (FormatException: Unexpected character (at character 2)
{token: eyJh...
 ^  

获取值并将其传递给提供程序的函数如下

   Future<void> insertUsertolocal() async {
        final storage = new LocalStorage();
        final _user = await storage.getValue(Constants.USER); // retrieves data from key
        User user = User.fromJson(jsonDecode(_user)); // receives FortmatException
        print(user.email);
}

json数据以字符串的形式存储在共享首选项中

_localStorage.setValue(Constants.USER, user.toString());

如何解决此问题？？

Answer 1

您应该在_localStorage.setValue中使用jsonEncode()。

请在此处查看文档：https://flutter.dev/docs/development/data-and-backend/json#serializing-json-manually-using-dartconvert