Android Gradle build with sub projects

Question

I am currently in the process of converting one of our projects to Gradle from maven. The folder structure is as follows:

gitRoot     settings.gradle     build.gradle     ProjectA         build.gradle         src/main/java     Libraries         SomeLib (git submodule)         ProjectBRoot (git submodule)             settings.gradle             build.gradle             ProjectB                 build.gradle                 src/main/java             Libraries                 FacebookSDK/facebook                     build.gradle                     src 

So already it looks complicated. But the idea is that ProjectB is a library project and it should be able to be built and packaged separately, which is why it has its own settings.gradle and as far as i can tell it seems to be working ok, i have it building and its finding facebook just fine.

The ProjectB/build.gradle contains this line

compile project(':libraries:facebook-android-sdk:facebook') 

The ProjectBRoot/settings.gradle contains this line

include ':ProjectB', ':libraries:facebook-android-sdk:facebook' 

The gitRoot/settings.gradle contains this line

include ':ProjectA', ':Libraries:ProjectBRoot:ProjectB' 

The ProjectA/build.gradle contains this line

compile project(':Libraries:ProjectBRoot:ProjectB') 

When I run the build i get this error

The TaskContainer.add() method has been deprecated and is scheduled to be removed in Gradle 2.0. Please use the create() method instead.  FAILURE: Build failed with an exception.  * Where: Build file '/gitRoot/Libraries/ProjectBRoot/ProjectB/build.gradle' line: 17  * What went wrong: A problem occurred evaluating project ':Libraries:ProjectBRoot:ProjectB'. > Project with path ':libraries:facebook-android-sdk:facebook' could not be found in project ':Libraries:ProjectBRoot:ProjectB'.  * Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.  BUILD FAILED  Total time: 4.652 secs 

So my guess as to whats wrong is that facebook is not in a direct subfolder from ProjectB...but that doesn't matter when building within ProjectBRoot. This is probably due to the face that I am referencing ProjectB directly and not through the ProjectBRoot/gradle.build but I tried that and it also did not work. Can someone please help me out, I have looked through the documentation and it doesn't talk about multiple projects that have their own settings.gradle files and I think thats the thing that is messing me up.

Update:

So I followed Xav's answer and I am now able to build with the command line however i can't import/build with android studio. I know the problem is still with the facebook project. The error i get is that it could not configure ProjectB.

 Gradle: A problem occurred configuring project ':ProjectA'.    > Failed to notify project evaluation listener.      > A problem occurred configuring project ':Libraries:ProjectBRoot:ProjectB'.        > Failed to notify project evaluation listener.          > Configuration with name 'default' not found. 

The error is caused by the line

 compile project(':facebook-sdk') 

inside the ProjectB/build.gradle

Answer 1

settings.gradle must define all the modules. It won't load other settings.gradle found in the tree to load more module.

You'll have to either

1. define a module for the facebook SDK in the top level settings.gradle. Yes it's redundant with the other settings.gradle.

2. publish Project B somehow (as well as its dependencies so in this case the facebook SDK library), somewhere (a corporate artifact repository for instance) and access it from Project A.

While #1 is better, it makes the ProjectB -> Facebook dependency tricky as the path will be different depending on the settings.gradle used. One way to fix this is to split the module name/path from its actual location on disk. this is done inside the settings.gradle file.

In your top level settings.gradle file, do

include 'facebook-sdk' project(':facebook-sdk').projectDir = new File('Libraries/ProjectBRoot/Libraries/FacebookSDK/facebook') 

In the setting.gradle file inside your Project B, do the same with the different relative path:

include 'facebook-sdk' project(':facebook-sdk').projectDir = new File('Libraries/FacebookSDK/facebook') 

This makes both project setup define the same 'facebook-sdk' module located at the same absolute location on disk.

All projects depending on this module should just declare the dependency as

compile project(':facebook-sdk')