Here’s my set of commands I always use in order to tag the entire tree.

It leaves some folder such as dalvik, external & ndk behind.

find . -type f \( -name "*.java" -o -name "*.c" -o -name "*.cpp" -o -name "*.h" \) -and -not \( -path "./out/*" -o -path "./prebuilts/*" -o -path "./external/*" -o -path "./dalvik/*"  -o -path "./ndk/*"  \) > cscope.files
cscope -b -q -k