Android.mk - build all source file in a directory

Android.mk - build all source file in a directory

I am using Android NDK to build my cocos2dx project, within the
Android.mk, there is a definition for LOCAL_SRC_FILES where each of the
cpp file are listed. Whenever I added a new source file, I'd need to add
it there as well... it looks like this:
LOCAL_SRC_FILES := hellocpp/main.cpp \
hellocpp/myclass.cpp \
hellocpp/mynextclass.cpp \
../../Classes/Screens/LaunchScreen.cpp \
the header file, however, can specify the entire directory to include, it
looks like this:
LOCAL_C_INCLUDES := $(LOCAL_PATH)/hellocpp
LOCAL_C_INCLUDES += $(LOCAL_PATH)/../../Classes/Screens
I have tried various ways to include the whole directory instead of single
file for the LOCAL_SRC_FILES so that I don't need to modify the Android.mk
build script whenever I add a new file, however, so far all my attempts
failed.
I have tried this:
#SRC_PATH_HELLOCPP := $(wildcard hellocpp/*.cpp)
#SRC_PATH_CLASSES += $(wildcard ../../Classes/*.cpp)
#LOCAL_SRC_FILES := $(SRC_PATH_HELLOCPP:$(LOCAL_PATH/%=%)
#LOCAL_SRC_FILES += $(SRC_PATH_CLASSES:$(LOCAL_PATH/%=%)
as well as this:
#LOCAL_SRC_FILES += hellocpp/*.cpp
#LOCAL_SRC_FILES += ../../Classes/*.cpp
both are not working...
I have another project that works well with the first option though, I
really do not understand why it doesn't work in the cocos2dx project...
does anybody know why or know the solution? Or maybe I should just leave
it as is and take the trouble, since everybody is doing that., but it is
really troublesome, hope somebody can help so that all of us can be more
productive..
Thanks!