类结构具有多个子表ContentProvider的 [英] Class structure for a ContentProvider having multiple sub tables

问题描述

该ContentProvider的医生说，使你的ContentProvider类的Andr​​oidManifest一个条目。如果你的类支持多个子表，那么就必须为每宣布一件CONTENT_URI不变。怎么样？不能对每个子表做，除非你子类。为什么不只是有多个供应商？

你实现分表提供者的后裔？随着多个子表，但仍然只有一个ContentProvider类？

正如你所看到的，我的文档混淆。其内容如下：

  

定义一个公共静态最终乌里命名   CONTENT_URI。这是字符串   再presents全文：URI的   内容提供商处理。您   必须定义这个唯一的字符串   值。最好的解决方法是使用   的完全限定类名   内容提供商（小写）。所以，   例如，该URI为   TransportationProvider类可能是   定义如下：

 公共静态最终乌里CONTENT_URI =
               Uri.parse（内容：//com.example.$c$clab.transporationprovider）;
 

如果供应商有子表，也可以定义CONTENT_URI常量为每个子表。这些URI应该都具有相同的机构（自标识内容提供商），以及仅由它们的路径区分。例如：

 内容：//com.example.$c$clab.transporationprovider/train
内容：//com.example.$c$clab.transporationprovider/air/domestic
内容：//com.example.$c$clab.transporationprovider/air/international
 

那么，有多少班做我们创建办理列车，空气/国内空运/国际？

解决方案

  

如果你的类支持多个   子表则必须有一个   CONTENT_URI不断宣布参加   每。怎么样？你不能这样做，除非   你的子类，用于每个子表

不要他们的名字全部 CONTENT_URI ，然后。这个名字是对第三方多大用处，反正，因为他们将无法访问您的源$ C ​​$ C访问静态数据成员。文档弄得我也一样，我甚至有点人云亦云他们的指示在我的一本书，但我从逐渐远离，将被改造我的材料相匹配。

一个更好的地方，看看是他们自己的内容提供者（ ContactsContract ， CallLog 等）。

  

你实现分表   提供者的后裔？随着   多个子表，仍有   只有一个ContentProvider类？

有你想要的。你可以用一个单独的类做到这一点，或者内部类（见 ContactsContract ），或者什么的。

The ContentProvider doc says to make ONE entry in the AndroidManifest for your ContentProvider class. If your class supports multiple sub-tables then there must be one CONTENT_URI constant declared for each. How? You can't do that unless you sub-class for each sub-table. Why not just have multiple providers?

Do you implement the sub-table providers as descendants? With multiple sub-tables, there is still only ONE ContentProvider class?

As you can see, I'm confused by the documentation. It reads:

Define a public static final Uri named CONTENT_URI. This is the string that represents the full content: URI that your content provider handles. You must define a unique string for this value. The best solution is to use the fully-qualified class name of the content provider (made lowercase). So, for example, the URI for a TransportationProvider class could be defined as follows:

public static final Uri CONTENT_URI = 
               Uri.parse("content://com.example.codelab.transporationprovider");

If the provider has subtables, also define CONTENT_URI constants for each of the subtables. These URIs should all have the same authority (since that identifies the content provider), and be distinguished only by their paths. For example:

content://com.example.codelab.transporationprovider/train 
content://com.example.codelab.transporationprovider/air/domestic 
content://com.example.codelab.transporationprovider/air/international

So, how many classes do we create to handle train, air/domestic and air/international?

解决方案

If your class supports multiple sub-tables then there must be one CONTENT_URI constant declared for each. How? You can't do that unless you sub-class for each sub-table.

Don't name them all CONTENT_URI, then. That name isn't terribly useful for third parties, anyway, since they won't have access to your source code to access that static data member. The documentation confused me too, and I even kinda parrot their instructions in my one book, but I am moving away from that and will be revamping my materials to match.

A better place to look is their own content providers (ContactsContract, CallLog, etc.).

Do you implement the sub-table providers as descendants? With multiple sub-tables, there is still only ONE ContentProvider class?

Have as many as you want. You can do it with a single class, or with inner classes (see ContactsContract), or whatever.

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