I save a List to an index in a Hive Box. 

class Person { 
 String name;
 Person(this.name);
}

List<Person> friends = [];
friends.add(Person('Jerry'));

var accountBox ,flutter,dart,flutter-hive"/>
	














    

		

        

            
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首页  > 解决方案 > 读取 Hivebox 值正在返回 List而不是保存的列表

I save a List to an index in a Hive Box. 



class Person { 
 String name;
 Person(this.name);
}

List<Person> friends = [];
friends.add(Person('Jerry'));

var accountBox 












flutter - 读取 Hivebox 值正在返回 List而不是保存的列表

I save a List to an index in a Hive Box. 



class Person { 
 String name;
 Person(this.name);
}

List<Person> friends = [];
friends.add(Person('Jerry'));

var accountBox 





问题描述



I save a List to an index in a Hive Box. 



class Person { 
 String name;
 Person(this.name);
}

List<Person> friends = [];
friends.add(Person('Jerry'));

var accountBox = Hive.openBox('account');
accountBox.put('friends',friends);

//Testing as soon as saved to make sure it's storing correctly.
List<Person> friends = accountBox.get('friends');
assert(friends.length == 1);




so all this works as intended. 
For some crazy reason when I hot restart the app and try to get the list of friends from Hive, it no longer returns a List<Person>. It returns a List<dynamic>



var accountBox = Hive.openBox('account');
List<Person> friends = accountBox.get('friends');

///ERROR
E/flutter (31497): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled
Exception: type 'List<dynamic>' is not a subtype of type 'List<Person>'
E/flutter (31497): <asynchronous suspension>
etc...




What could be causing this? It's so unusual. 







How to map array using ObjectMapper?


Here is my model



class ResponseDataType: Mappable {

    var status: Int?
    var message: String?
    var info: [Info]?

    required init?(map: Map) { }

    func mapping(map: Map) {
        status <- map["status"]
        message <- map["message"]
        info <- map["member_info"]
    }
}




Here is my JSON



"status": 200,
    "data": {
        "member_info": [
            {
                "fullname": "werwerwer",
                "type": "werwer",
                "profile_image": "sdfsdfsd.jpg",
                "email": "wfwe@werwegt",
                "contact": ""
            }
        ]
    },
    "message": "Login Success"
}




Im having a hard time mapping the array inside the data. Please tell me what is wrong with my code.


标签： flutterdartflutter-hive


解决方案









Hive 主要是具有文件缓存的内存数据库。当应用程序运行时，它可能会将您放入其中的对象按原样存储在内存中，但将对象作为序列化二进制数据存储在缓存文件中。这意味着只要应用程序处于打开状态，您就会取回您的Person列表，但它不知道如何从缓存文件中获取该数据。结果是 Hive 尽最大努力反序列化数据并将其作为dynamic.



如果您想在应用程序关闭后保持数据完整，您需要告诉 Hive 如何（反）序列化您的类型。为此，请使用 Hive 注释适当地标记您的类。



@HiveType(typeId: 0)
class Person extends HiveObject { 
  @HiveField(0)
  String name;

  Person(this.name);
}











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