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问题描述

我创建了一个包含一个Rails服务器：用户和相关的：评论。它被用作一个Android客户后端的API。交换格式加载并在服务器上存储数据是JSON。以下是相关的迁移。

I created a Rails server that contains :users and associated :comments. It is used as a backend API for an Android client. The exchange format to load and store data at the server is JSON. Here are the relevant migrations.

class CreateUsers < ActiveRecord::Migration
  def change
    create_table :users do |t|
      t.string :name
      t.timestamps
    end
  end
end

...

class CreateComments < ActiveRecord::Migration
  def change
    create_table :comments do |t|
      t.references :users
      t.string :subject
      t.text :message
      t.timestamps
    end
  end
end

所有用户都已经导入。因此，只读访问配置为：用户资源。因此，对于：评论应该是可以添加新条目。下面是可用的路由。

All users have already been imported. Therefore, only read access is configured for the :users resource. Thus, for :comments it should be possible to add new entries. Here are the available routes.

   user_comments GET   /users/:user_id/comments(.:format)      comments#index
                 POST  /users/:user_id/comments(.:format)      comments#create
new_user_comment GET   /users/:user_id/comments/new(.:format)  comments#new
    user_comment GET   /users/:user_id/comments/:id(.:format)  comments#show
           users GET   /users(.:format)                        users#index
            user GET   /users/:id(.:format)                    users#show

Android客户端

在客户端我用的是服务与 AsyncTasks 来下载，分析并存储用户到本地的SQLite数据库。 A 的ContentProvider 提供缓存用户到用户界面。从服务器下载的用户对象包含用户表的唯一ID。当一个新的评论获取客户机上创建这个应该是很有用的。

Android client

On the client side I use a Service with AsyncTasks to download, parse and store users into a local SQLite database. A ContentProvider delivers cached users to the UI. The user object downloaded from the server contains the unique id of the users table. This should be useful when a new comment gets created on the client.

在用户显示在Android客户端上的列表视图。
系统用户项目被选中。
列表活动创建一个意图，其中包含了用户特定的URI，例如： 内容：//com.example.myapp.provider/users/23
在用户活动显示有关用户和相关注释详细信息。
在缓存的意见得到通过 CursorLoader 加载。（1）
一个同步进程加载的意见。（2）

Users are displayed in a list view on the Android client.
A user item gets selected.
The list activity creates an Intent which contains the user specific URI, e.g. content://com.example.myapp.provider/users/23.
A user activity displays detail information about the user and associated comments.
Cached comments get loaded via a CursorLoader. (1)
A synchronization process loads comments from the remote server. (2)

注释可从用户活动创建。
注释被存储到本地数据库。（3）
存储注释sychronized与远程服务器。（2）

我标志着与以下问题相关的方案步骤。

I marked the scenario steps that are associated with the following questions.

如何创建内容的URI意见被在用户活动中使用了 CursorLoader ？请介意的话，我只知道用户URI在这一点上。
有人可以描述我是如何创建一个同步过程？我不知道，如果一个SyncAdapter在这里工作（从来没有使用过）。是同步过程只是一个code>服务是，一方面开始任务下载，分析并存储在客户端上，并在另一方面负载意见，EN codeS并发送意见到服务器？
如何进行内容的URI一个新的评论是什么样子？是的ContentProvider 征求意见的相同用户？是否有只有一个 SQLiteOpenHelper 应用程序？

How do I create a content URI for the comments being used with a CursorLoader in the user activity? Please mind, I only know the user URI at this point.
Can someone describe how I create a synchronization process? I am not sure if a SyncAdapter works here (never used it). Is the the synchronization process just a Service that on the one hand starts tasks to download, parse and store comments on the client and on the other hand loads, encodes and sends out comments to the server?
How does the content URI for a new comment look like? Is the ContentProvider for comments the same as for users? Is there only one SQLiteOpenHelper in the application?

主要的问题，我挣扎是如何设计的应用程序？如果你知道如何，我应该同步的用户和他们的相关评论一个更好的解决方案，你都非常欢迎。

The main problem I am struggling with is how to design the application? If you know of a better solution on how I should synchronize the users and their associated comments, you are very welcome.

回答以下问题1和3。
我延长了REST模式如下：JSON哈希返回一个的评论的现在包含的相关的用户的的的 ID 的。同样的 ID 的也包括在JSON哈希值的用户的。这两个对象都存储在Android设备上的本地数据库。这让我请求的评论的特定的用户的。我只是通过的服务器用户ID 的是，其中条款。内容的URI的评论的是不是级联，因为我暗示我的问题。它类似于用户的内容URI：

Answers to question 1. and 3.
I extended the REST model as follows: The JSON hash returned for a comment now includes the id of the associated user. The same id is also included in the JSON hash for the user. Both objects are stored into the local database on the Android device. This allows me request comments for a specific user. I simply pass the server user id as WHERE clause. The content URI for comments is not cascaded as I implied with my question. It is similar to the user content URI:

内容：//com.example.myapp.provider.commentsprovider/comments

请注意，我改变了字符串的权限的一部分。我决定创建separate内容提供商获得的用户和评论的。

Note, that I changed the authority part of the string. I decided to create separate content provider for users and comments.

CursorLoader