Android - How to regenerate R class? [duplicate]

Answer 1

You can also right click on the project -> Android Tools -> Fix Project Properties. That should cause the R.java class to be re-generated.

Answer 2

In order to regenerate the R.class, you will have to try multiple techniques.

• Remove any R imports from your java source files: import R.android
• Make sure to open the "Problems" panel by going to Window->Show view->Problems
• If you do have some errors in your xml resources, you will need to correct those errors. In my case I had to change my id attributes to include the "+" sign as follows: android:id="@+id/grp_txt"
• Now proceed to do Project->Clean
• Finally do Project->Close, Project->Open

The "+" sign indicates a new resource id and the forces the aapt tool to create a new resource integer in the R.java class.

Answer 3

Ok, I fixed it:

When I changed manifest to target 1.5 version, million errors appeared and only one wasn't related to inexistance of R class - in manifest file attributes "targetSdkVersion" and "maxSdkVersion" did not exist in sdk 1.5

Because of this R class was not able to generate.

Answer 4

To generate the R file again:

1. Modify something in layout->activity_main.xml
2. Save the file
3. Project->Clean...

Just delete the R file located in gen directory, and then try Project->Clean. Then build your app again.

Answer 5

My problem was errors in my XML files. Errors aren't always automatically detected in the Android Common XML Editor or Android Common Manifest Editor, so try using the regular text editor instead. For example, somehow some random gibberish from a .java file had been inserted into my manifest and strings.xml files.

Right click on any XML files (most likely in the /res folder or AndroidManifest.xml) and click "Open With," then select "Text editor." Make sure everything looks good and then save. Also, make sure to enable "Build Automatically" for your project. I had deleted my R.java file and it was rebuilt from scratch, so no need to restore it from local history.

Answer 6

If you accidently deleted your R in eclipse by "project clean" (don´t do this) Rightclick on your Projectfile -> Restore from local History...

recreate your R

My Case:

• Broken xml caused bug in R. (because of ä, ö, ü, letters in id)
• clean project deleted my R.

What I Did:

• recreated R from local History
• checked for wrong R imports in my classes (like import android.R) and removed them
• fixed that xml file and saved its content in an external txt file
• deleted the xml completely from my project.
• ran my project one time
• put that fixed xml back at its place

and...

• gave my girlfriend a big hug without a reason after freaking out like a Hulk.