Trying to compile java source with javac: package R does not exist

Question

I get this error compiling java sources into classes using javac.

There's the only layout for MainActivity in the res folder, I generated R.java with aapt2 and imported it.

I used the following to create R.java :

aapt2 link --manifest AndroidManifest.xml -I android.jar -R co/layout_activity_main.xml.flat --java 

And here are the errors that I am getting.

javac it/dummy/MainActivity.java -cp knoxsdk.jar:android.jar:it/
it/dummy/MainActivity.java:12: error: cannot find symbol
import it.dummy.R;
               ^
  symbol:   class R
  location: package it.dummy
it/dummy/MainActivity.java:19: error: package R does not exist
        setContentView(R.layout.activity_main);
                        ^
it/dummy/MainActivity.java:21: error: package R does not exist
        final Button activateBtn = findViewById(R.id.activateBtn);
                                                 ^
it/dummy/MainActivity.java:29: error: package R does not exist
        final Button installBtn = findViewById(R.id.installBtn);
                                                ^
it/dummy/MainActivity.java:37: error: package R does not exist
        final Button updateBtn = findViewById(R.id.updateBtn);
                                               ^
5 errors

Answer 1

I assume that R.java is in it/dummy/ and that MainActivity.java has package it.dummy; . What appears to be wrong is the classpath: should contain '.' instead of 'it/' :

javac it/dummy/MainActivity.java -cp knoxsdk.jar:android.jar:.

Answer 2

I think you need to compile your resource first in order to link them later with the link option as follows.

aapt2 compile -o co/res/ app/src/main/res/layout/layout_activity_main.xml

Also please see this answer for other options.