How to use non-standard (hidden) API classes?

I'm fairly new to Android and have gone through the basic tutorials. I thought I'd dig a little deeper and downloaded the source code to some of the "native" Android apps, like IM, Email, Voice Dialer, etc.

In importing the source of these native apps into Eclipse, I found that they reference c开发者_C百科lasses that are not in the 2.1 API, i.e. classes such as android.content.Entity, android.net.http.DomainNameChecker, etc. As a result, I can't compile and play with this code.

So is there is a "hidden" API that the native apps use that is not available to the regular app developers? Is there a "native" SDK I can use to import these classes?

David

As with all hidden API:s these are hidden for a reason and that is that they are used by the framework or specialized applications and are not guaranteed stable or suitable for general development. It is not advisable to use non-supported API:s for your applications since they might break on future releases etc. The ones that you mention are part of the framework and used internally by the Android system.

That said, if you just want to explore Android you may build your apps as part of the platform build system and test them with your own build from the open source projects.

The article "Using internal (com.android.internal) and hidden (@hide) APIs" by user inazaruk shows you step by step a method to import hidden Android APIs.