R.java File Just Went Missing

I'm working on my app and for this activity I was going to build a new layout file for it. However eclipse gave me an error stating that layout was not updated in the R.java file.

Solution 1:

Any error on XML files will prevent R generation. Check for mark errors and Eclipse console (some errors when parsing XML are shown there).

Also I've seen Eclipse generates some dumb files with .out.xml or .xml.out extensions. I'm not sure why it happens, but any "allien" file on res folder also prevents R to be regenerated.

Solution 2:

Thanks for your help guys. I tried to look at every file to check for errors but after 30 minutes of scratching my head, I just opened a new project and copied each file to the new project and that is working now.