R.java could not be opened/ doesnt exist

i've had errors in my project so i saved my files on desktop then deleted the project. i remade the project and pasted my source fil开发者_C百科e back in. it's saying R.java doesn't exist when it does.

any ideas?

thanks

Try to delete the file and then rebuild your project (a clean build could help too).

This file, R.java, is dynamically generated during build. You need to clean and then rebuild your project. This should resolve the issue.

if you're having the problem for every new project, it could be this:

"Debug certificate expired" error in Eclipse Android plugins

that's what fixed it for me, even though I wasn't getting any debug certificate errors. apparently the debug certificate is only valid for one year.