I\'m making a new Android project, with the standard \'app\' module, as well as a library project (let\'s call it \'custom_lib\'). In the app
In the "Build Variants" panel window on the left, you should see both of your modules, and next to them the current "active" variants. For instance
app debug
custom_lib debug
When calling Build > Make Project we are building every modules in the project in their current variant.
However, due to a current Gradle limitation (https://code.google.com/p/android/issues/detail?id=52962), building app in debug will require building the release variant of custom_lib, and so you end up building both.
I would recommend to not use Make Project but instead use the option below that says Make Module app. This option will change from app to lib based on the current selection in the Project panel or based on the current editor, and will always do only what's needed to build the current module.
(Looking into this, we noticed that there isn't a shortcut for it, so we're adding one).