OK, so I have a module called “gridbox” which is a layout widget I wrote a very long time ago.

Within gridbox is the file res/values/gridboxAttrs.xml which contains (abridged):

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <declare-styleable name="Gridbox_Layout">
    <attr name="layout_weightx" format="float" />
    <attr name="layout_weighty" format="float" />
 </declare-styleable>
</resources>

In my application module I have res/values/styles.xml which references resources defined above:

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <!-- Style for a normal button -->
  <style name="baseButton">
    <item name="android:gravity">center</item>
    <item name="layout_weightx">1</item>
    <item name="layout_weighty">1</item>
    <item name="android:layout_margin">1dip</item>
  </style>
</resources>

This built just fine under Eclipse, but Android Studio gives me

ERROR: /Users/falk/MyProject/MyApp/build/intermediates/packaged_res/debug/packageDebugResources/values/values.xml:372:5-384:11: AAPT: error: style attribute 'attr/layout_weightx (aka org.efalk.myapp.test:attr/layout_weightx)' not found.

I’m guessing I need to do something to get Android Studio to know that the module “MyApp” depends on module “Gridbox”. My MyApp/build.gradle file does end with

dependencies {
    implementation project(':Gridbox')
}

I have no idea what else I should be doing.