Unlike xcode in android project need compile.
so if change c++ code need compile
To compile in the terminal directory is project want to compile.

cocos compile -p android --android-studio

If want to compile with run.

cocos run -p android --android-studio

-p is select platform
-p android --android-studio
is to select android studio

-app-abi is compile cpu option
for example

cocos run -p android --android-studio -app-abi x86