I just updated the SDK tools in Eclipse to revision 22, and since then I cannot build my project. Specifically the R class is not recognized in my Activity (I was getting compiler errors) and even when I imported manually, again the import was not working.
Additionally the project gen folder is empty, and cleaning the project/workspace (having build automatically option on) didn't make any difference.
Is this a known issue? Did it happen to everyone? Is there a workaround? Maybe Google just wants us to switch to Android platform the soonest possible?
I had major issues with the update as well. In my case my project uses a library that also depends on another library. I found that I needed to check the box for Android Private Libraries in the order/export tab of the Java Build Path for the project - and each of my connected libraries -- to properly compile and run the app on a device.
Some others have indicated that you need to also check Android Dependencies too but that doesn't seem necessary for my project.