This small but mighty error gave me 4 hours of headache. Missing
R.Java file in the ‘gen’ folder, and
encountering ‘R cannot be resolved to a
variable’ each time I try to run the application.
Every single article I read said everything you already
there was to say.
- Check if you have import android.R ; and delete it. Next clean the solution and
rebuild. If it still is missing, restart eclipse.
- Make sure your SDK manager is up to date and install
the latest SDK Build tools.
- Check all the XML file names in the res folder
and make sure they are all in lowercase convention. Then clean/build and
restart eclipse.
- Inspect the AndroidManifest.xml and other xml files to ensure there are no errors and the suggestions go on and on and on……...
I tried all these and more, deleted and recreated my whole
project severally. Still no positive result. The R.Java file just refused to appear in the package under the ‘gen’
folder.
In fact, as opposed
to others who initially had this file but it later disappeared (hence right
clicking the ‘gen’ folder and selecting ‘Restore from Local History’ could
resolve their issue due to the fact that the R.Java file might have been deleted), mine NEVER was created at
all, even after deleting and re-creating new projects
Now I had ADT version 23 with highest API level of 21
(Android 5.0.1).
On creating the project, I was provided with drop downs “Target SDK” and “Compile With” where from which I was to select an API level. Not
selecting the highest API level in both instances made the issue with R.Java
file not being created and anywhere R was referenced in the program, it could
not be resolved.
So I had to SELECT
THE HIGHEST API LEVEL I HAD Installed and voila!!!!! Problem solved.
For Target SDK, select highest API you have installed
Similarly for Compile With, select highest API you have
installed
I hope this gives you one less headache.
