java - "Cannot resolve symbol "R" - all XML android:ids are correct -

java - "Cannot resolve symbol "R" - all XML android:ids are correct -

i edited little amount of xml code (tried add together android:src"@drawable/" didn't seem deleted after) , java code (added troop1p1.setvisibility(view.visible); end of onclicklistener, , 1 time again deleted afterwards [i had used findviewbyid troop1p1]).

however, whole code has stopped working, every "r" in (r.id.) beingness highlighted, text "cannot resolve symbol "r"" when hovered over.

in addition, when run code next error:

error: error: no resource found matches given name (at 'layout_above' value '@id/btntroop1p2').

however, i've checked , i'm sure i've correctly id'd btntroop1p2 using android:id="@+id/btntroop1p2", can't find problems there.

i'd appreciate help, want able run project again!

are using eclipse? .if yes go project -> clean... -> tick project name -> ok. give try. similar problems , solves me anyway.

java android xml r.java-file