Android Studio don't generate R.java for my import project

Question

I import a project to Android Studio , but the R.java is always empty.

public final class R {
}

I have tried:

1. Make project,ma

Answer 1

Goto File -> Settings -> Compiler now check use external build

then rebuild project

Answer 2

I managed to regenerate R: File->Settings->Compiler

then UNCHECK "Use in-process build"

Rebuild Project

Answer 3

Just use the 'Rebuild Project' from the 'Build' menu from the top menu bar.

Answer 4

In my case I had an empty line prior a drawable definition in xml. This was braking aapt essentially not allowing to generate R.java .

Answer 5

For me the problem with the R class has been related to automatically organized imports.

As AndroidStudio has the option to allow the automatic imports, it took the wrong R class and thats why the ids have not been found and Gradle was throwing errors!

So check if the import to the R class is referencing to the one you need.

Answer 6

If you are facing this problem in a specific module in your project, you could try opening just that module as a project and then build it. This worked for me. It was failing to generate the R file for the module when I was trying to re-build the entire project.