Uri on Activity.onActivityResult(int requestCode，int resultCode，Intent数据) [英] Uri on Activity.onActivityResult(int requestCode, int resultCode, Intent data)

问题描述

我对Android内容提供商的可靠性有些怀疑.

I have some doubts on the reliability of content providers in Android.

1-例如，不同的Document是否可能具有相同的Uri?

用户在设备中有2张图片:

1 - Is it possible for different Documents having the same Uri?

For instance. A user has 2 images in the device:

content://com.android.providers.media.documents/document/image%AAAAA

和

content://com.android.providers.media.documents/document/image%BBBBB

假设AAAAA指向文件，然后用户删除该文件.

Supposing a scenario where AAAAA would point to a file, then the user erases that file.

用户在系统中创建一个新文件，该新文件将收到AAAAA Uri.

这种情况会发生吗?

User then creates a new file in the system, and that new file receives the AAAAA Uri.

Can this scenario happen?

还是按顺序生成它们，以便首先创建CCCCC DDDDD等.我可以相信Uri始终指向同一文件实例(如果找不到该文件，则返回null友利)

2-Uri是否有可能指向已被重大更改的文档?

曾经是音频，现在是图像的文档是否具有与以前相同的标识符?我不是说用户已经更改了文件内容，而是一个隐式意图给了我一个Uri，我可以相信该设备中该文档的Uri是唯一的吗?

Or are they sequentially generated so that CCCCC DDDDDetc.. gets created first, in a way that I can trust Uri's to always point to the same file instance (or null if no document can be found by that Uri)?

2 - Is it possible for an Uri pointing to a document that has been significantly altered?

Can a document, that once was Audio, and now is an Image, have the same identifier that once had? I do not mean that the user has changed the file content, but rather an implicit intent gave me a Uri, can I trust that Uri to be unique, for that document in that device?

推荐答案

这种情况会发生吗?

Can this scenario happen?

是的

曾经是音频，现在是图像的文档，是否具有与以前相同的标识符?

Can a document, that once was Audio, and now is an Image, have the same identifier that once had?

是的

请注意，计算机中的几乎所有其他事物都适用相同的条件.例如，可以重复使用URL来指向不同的Web内容，包括具有不同MIME类型的内容.

Note that the same thing holds true for pretty much everything else in computers. For example, a URL can be reused to point to different Web content, including content with a different MIME type.

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