Android FirBase RealTimeDb JsonTree设计,基于RealTime聊天的json格式

这一次,我要用 FirBase RealTimeDb实时数据库写个聊天的demo,在存储数据和查询数据时需要规划一下json数据格式,要不然后期就蒙圈了,google的官方文章如下:
https://firebase.google.com/docs/database/android/structure-data
为举例说明为什么嵌套数据不正确，现假设一个如下所示的多层嵌套结构：

{

  // This is a poorly nested data architecture, because iterating the children

  // of the "chats" node to get a list of conversation titles requires

  // potentially downloading hundreds of megabytes of messages

  "chats": {

    "one": {

      "title": "Historical Tech Pioneers",

      "messages": {

        "m1": { "sender": "ghopper", "message": "Relay malfunction found. Cause: moth." },

        "m2": { ... },

        // a very long list of messages

      }

    },

    "two": { ... }

  }

}
若采用这种嵌套设计，循环访问数据就会出现问题。例如，要列出聊天对话标题，就需要将整个 chats 树（包括所有成员和消息）都下载到客户端。

平展数据结构

如果数据被拆分到不同路径（又称反规范化），则可根据需要通过不同调用有效地下载。 请考虑此平面化结构：

{

  // Chats contains only meta info about each conversation

  // stored under the chats's unique ID

  "chats": {

    "one": {

      "title": "Historical Tech Pioneers",

      "lastMessage": "ghopper: Relay malfunction found. Cause: moth.",

      "timestamp": 1459361875666

    },

    "two": { ... },

    "three": { ... }

  },

  // Conversation members are easily accessible

  // and stored by chat conversation ID

  "members": {

    // we'll talk about indices like this below

    "one": {

      "ghopper": true,

      "alovelace": true,

      "eclarke": true

    },

    "two": { ... },

    "three": { ... }

  },

  // Messages are separate from data we may want to iterate quickly

  // but still easily paginated and queried, and organized by chat

  // converation ID

  "messages": {

    "one": {

      "m1": {

        "name": "eclarke",

        "message": "The relay seems to be malfunctioning.",

        "timestamp": 1459361875337

      },

      "m2": { ... },

      "m3": { ... }

    }
4000
,

    "two": { ... },

    "three": { ... }

  }

}

官方的建议还是要才用的,淡然,我觉得官方给的第二层结构"members"这个对我来说并没有什么用,于是我打算把它去掉,google核心的思想就是避免嵌套,遵循这一原则,我稍微修改了官方的json结构最终是下面的.

存储聊天内容的json

{

  "chats": {

    chatlist: [

      {

        {

          "title": "Historical Tech Pioneers",

          "lastMessage": "ghopper: Relay malfunction found. Cause: moth.",

          "timestamp": 1459361875666,

          "member": "天涯恋",

          "fridlogo": "pic",
 "messageid": "青青"

        }

      }

    ]

  },

  "messages": {

     "messages": {

    "青青": {[

      {

        "name": "eclarke",

        "message": "The relay seems to be malfunctioning.",

        "timestamp": 1459361875337

      }]

    }

  }

}

在chats对象中可以查看到聊天的数量,和哪个好友,头像,时间,对方id,拿到id后可以在message信息中获取好友的聊天记录

存储用户信息的json,这个没啥好说的,保存所有用户的信息

{

  users:{userid:

    {

      "id": "00000000-0000-0000-0000-000000000000",

      "createTime": "0001-01-01 00:00:00",

      "level": 0,

      "nick": "string",

      "gender": false,

      "birthday": "0001-01-01 00:00:00",

      "cellphoneNumber": "string",

      "emailAddress": "string",

      "name": "string",

      "picture": "string""address": "string"

    }

    } 

}