Error in all the classes files: R cannot be resolved

Question

Example code:

setContentView(R.layout.main);

Error:

R cannot be resolved

There\'s this error in all the class

Answer 1

Yesterday, I made an update with sdk manager, and I had the same problem as you. I fixed the issue: I have updated another time the android sdk (with the sdk manager tool), then I check update from eclipse for install the updated ADT plugin and I rebuid my project. "Android sdk Build-tools" from Android sdk manager is now rev 17 and now it is OK. I think the issue is from adt plugin from eclipse