Clean in Eclipse temporarily destroys Android project with error message: missing required source folder: 'gen'

Question

I am experiencing an annoying problem with an Android project in Eclipse. All my other Android projects are okey (at the moment). Whenever I perform a clean (Menu:Project->Clean...) the project gives an error and I can't compile/run the app. The error is:

Project 'Project Name' is missing required source folder: 'gen'

As soon as I edit some code the problem disappears until I perform a clean again. I can also right-click on the gen-folder and delete it. Eclipse will recreate the gen-folder and the problem disappears until I perform a clean. This is not a showstopper but it is really annoying since I sometimes have to do a clean before I run the app.

I'm using the following:
OS: Ubuntu 10.04 (Linux CYLON 2.6.32-24-generic)
Eclipse: Helios Release (Build id: 20100617-1415)
Android dev tools: 0.9.7.v201005071157-36220 (the latest as of today)

Answer 1

AFAIK, If Everything is Perfect you have know need to touch or delete the gen Folder.

As soon as I edit some code the problem disappears until I perform a clean again.

What are the things you have changed in your code. Mainly about the Resources. It makes the difference upto my knowledge. dont see only the Logcat and Consider the Console window also shows some error in the red color. First clear that errors and then clean and build your project.

Edit:

Check for:

1. Is there Android Package is Missing?
2. Right Click--> Properties--> Java Build Path--> Order and Suppport Tab--> Check res or src folders are selected?