> The problem is, there are more Content Providers in the system than are documented in that package, and while you can use them, you probably shouldn’t. They’re there because some of the Google-provided apps use them internally to access their own data resources. Because Android is an open-source project, it’s easy enough to find them just by running shell commands like find and grep over the source tree.
> [...]
> Back to Content Providers. For example, there’s one inside the built-in Messaging (A.K.A. texting or SMS) app that it uses to display and search your history. Just because it’s there doesn’t mean you should use it. The Android team isn’t promising that it’ll be the same in the next release or even that it’ll be there in the next release.
> So, go ahead and look at the undocumented Content Providers; the code is full of good ideas to learn from. But don’t use them. And if you do, when bad things happen you’re pretty well on your own.
http://android-developers.blogspot.de/2010/05/be-careful-wit... http://www.tbray.org/ongoing/When/201x/2010/05/06/Private-AP...
The main point here is that you are on the same level of Google: if you want you can use those private APIs, but be ready to do a lot of work to keep your application working fine.