I changed from R to R2 but the ID underlines it with the following text:
Static member 'null.R2.id' accessed via instance reference

and when I try running the code it throws this error:

java.lang.annotation.AnnotationTypeMismatchException: Incorrectly typed data found for annotation element public abstract int butterknife.BindView.value() (Found data of type R2.id)
    at jdk.compiler/com.sun.tools.javac.model.AnnotationProxyMaker$ValueVisitor$1AnnotationTypeMismatchExceptionProxy.generateException(AnnotationProxyMaker.java:271)
    at java.base/sun.reflect.annotation.AnnotationInvocationHandler.invoke(AnnotationInvocationHandler.java:89)