使用_data场的Android数据库（自定义内容提供商）存储的文件 - V1.6 [英] Storing file in Android Database (Custom Content Provider) using _data field - v1.6
问题描述
我一直缠斗在我的Android应用程序的问题。我一直在读Android的文档，我的书在Android（安卓临2），并看着几乎每一个例子，我可以得到我的手，但无法弄清楚如何实施文件的存储（图像，二进制数据）对由内容提供者暴露在SQLite表记录
I have been battling with an issue in my Android app. I have been reading Android docs, my book on Android (Andriod Pro 2) and have looked at almost each and every example I could get my hands on but could not figure out how to implement storing of files (images, binary data) against records in Sqlite table exposed by the content provider.
下面是我做了什么（几乎类似记事本示例应用程序）：
Here is what I have done (almost similar to Notepad sample app):
- 在我的供应商实施
的ContentProvider。它所有的工作进行CRUD操作。在内部，它使用一个执行SQLiteOpenHelper（pretty的标准的东西） - 在我添加类型文本
_data 列 - 在我插入一条记录，并得到URI回
- 呼叫openOutputStream上的内容提供商，并开始将数据写入
- Implemented
ContentProviderin my provider. It all works for CRUD operations. Internally it uses an implementationSQLiteOpenHelper(pretty standard stuff) - I have added a
_datacolumn of type text - I insert a record and get the Uri back
- Call openOutputStream on the content provider and start writing the data
根据Android的临2 book.Here这恰恰是code这部分的片段：
This is exactly according to the Android Pro 2 book.Here is the snippet of that part of code:
Uri uri = getContentResolver().insert(MyAuthority.CONTENT_URI, contentValues);
OutputStream s = getContentResolver().openOutputStream(uri);
不过，我得到以下错误：
But I get the error below:
1月十一日至29日：07：30.717： WARN / System.err的（1490）： java.io.FileNotFoundException：无 在文件支持的供应商 内容：// myproviderauthority /播客/ 1
11-29 01:07:30.717: WARN/System.err(1490): java.io.FileNotFoundException: No files supported by provider at content://myproviderauthority/podcasts/1
什么是我需要做什么？我读的Android 文档但他们都非常含糊：
What do I need to do? I read Android documentation but they are very vague:
这暴露了数据字段 客户实际上应该包含一个 内容：URI字符串
the field that exposes the data to clients should actually contain a content: URI string.
1），那么请问字段类型必须是文本还是有一个特殊的内容：URI字符串数据类型
1) So does the field type need to be TEXT or is there a special content: URI string data type?
2）在插入我没有URI的时间。我需要得到URI插入后，然后更新记录中的那场？
该记录还应该有另一个 现场，名为_data，列出了 该设备适用于以确切的文件路径 文件。该字段不旨在是 由客户机读的，而是由 ContentResolver的。
The record should also have another field, named "_data" that lists the exact file path on the device for that file. This field is not intended to be read by the client, but by the ContentResolver.
3）那么，应该是这个字段的类型是什么？文本 - ？我认为
客户端将调用 ContentResolver.openInputStream上（） 用户面向字段保持该URI 为项
The client will call ContentResolver.openInputStream() on the user-facing field holding the URI for the item.
4）这是绝对的垃圾！我怎么能叫 ContentResolver.openInputStream（）在球场上？你只能把这种记录在案并通过URI。
4) This is utter rubbish! How can I call ContentResolver.openInputStream() on the field?? You can only call this on the record and passing the Uri.
感谢您的时间，我希望你能帮助我。我还审查了这些SO问题（<一href="http://stackoverflow.com/questions/3883211/how-to-store-large-blobs-in-an-android-content-provider">this和<一href="http://stackoverflow.com/questions/3926553/getcontentresolver-openoutputstreamuri-no-files-supported-by-provider">this)他们并没有帮助。
Thank you for your time and I hope you can help me. I have also reviewed these SO questions (this and this) and they did not help.
顺便说一句，我对建筑的API等级4（1.6版本）。的
推荐答案
要看到无由供应商在...支持的文件的来源，看看<一href="http://stackoverflow.com/questions/3883211/how-to-store-large-blobs-in-an-android-content-provider/4336013#4336013">here.这种情况似乎与你所描述的非常相似。
To see where "No files supported by provider at..." comes from, have a look here. The situation there seems very similar with the one you've described.
总之，你的内容提供商（或它的一些超）需要重写和实施中openFile 方法。这引发错误由默认的未实现 - 后退！ code。在 ContentProvider.java 。
In short, your content provider (or some of its superclasses) needs to override and implement openFile method. That error is raised by the default "not implemented--back off!" code in ContentProvider.java.
我发现它有助于在底层源$ C $构架了C偷看当我遇到问题，因为文件有时有点欠缺。
I find it helpful to peek at underlying source code of the framework when I get stuck, since documentation is sometimes a bit lacking.
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