R cannot be resolved-android

R cannot be resolved R.lay开发者_运维技巧out.main cannot be resolved error is repeating to me and i cant run any of my android program

pls give any instruction

also probably delete this line which sometimes creeps up :

import android.R or something like that.

Are you using Eclipse? Try project -> clean

Otherwise: check your console in the bottom for errors that need fixing before your R is build

I just had a reoccurence of the dreaded "R cannot be resolved" error, and I went through all the usual fixes; make sure all resources have lower case names, do a clean, make sure there isn't an import android.R lurking somewhere... no luck.

After a couple of frustrating hours I realised I had saved a PaintShop Pro format file (something.psp) in a resource folder in the file system and Eclipse was pulling it into my res folder. Not being a .png, it choked, and that seemed to cause the problem. As soon as I removed the .psp the error disappeared.

Hope this helps prevent someone else pulling out their hair.