Cannot resolve Symbol variables - Tearing my hair out -

i trying follow tutorial , have got stuck figure last error before completion.

can tell me doing wrong these variables? including both activities below, if other code applicable, happy provide it.

error codes read: error:(21, 56) error: cannot find symbol variable pickupline error:(24, 9) error: cannot find symbol variable retrybutton error:execution failed task ':app:compiledebugjavawithjavac'.

compilation failed; see compiler error output details.

mainactivity.java:

package io.wavey.pickuplesson1;  import android.content.intent; import android.support.v7.app.appcompatactivity; import android.os.bundle; import android.view.view; import android.widget.button;  public class mainactivity extends appcompatactivity {  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);      // grab clean button can stuff it!     button cleanbutton = (button) findviewbyid(r.id.cleanbutton);     final button dirtybutton = (button) findviewbyid(r.id.dirtybutton);       final string pickupline = "you had me @ hello world";      //this callback.     cleanbutton.setonclicklistener(new view.onclicklistener() {         @override         public void onclick(view v) {             sendline(pickupline);         }     });   } //send activity private void sendline(string pickupline) {     intent intent = new intent(this, lineactivity.class);     intent.putextra("pickup line", pickupline);      startactivity(intent); } } 

lineactivity.java:

 @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_line);      bundle pickupdata = getintent().getextras();      if (pickupdata == null) {         return;     }     string receivedpickupline = pickupdata.getstring("pickup line");     textview newline = (textview) findviewbyid(r.id.pickupline);     newline.settext(receivedpickupline);      retrybutton.setonclicklistener (new view.onclicklistener() {         @override         public void onclick(view v) {             finish();         }     });           }     } 

lineactivity.java: