gradle cannto find subproject of dependency -

i have following structure:

./mainproject/     -settings.gradle     -build.gradle     -subproject/         -build.gradle         -/src/... ./libraryproject     -settings.gradle     -build.gradle     -subproject_interfaces/         -build.gradle         -src/...     -subproject_impl/         -build.gradle         -src/... 

libraryproject/settings.gralde:

rootproject.name = 'library' include 'subproject_interfaces','subproject_impl' 

libraryproject/build.gradle

dependencies {     compile project(':subproject_interfaces')     compile project(':subprojects_impl') } 

mainproject/settings.gradle

include "library" project(':library').projectdir = new file(settingsdir,"../libraryproject") 

mainproject/subproject/build.gradle

dependencies{     compile project(':library') } 

• i can gradle build libraryproject fine.
• i can gradle build libraryproject via project dependency on mainproject fine.
• i cannot build mainproject due to: project path: 'subproject_interfaces' not found in project ' library'

you misunderstood multi-project feature.
in 1 multi-project build have one settings.gradle , there have build whole project tree.
cannot delegate main build settings.gradle library build settings.gradle.
if want work that, have include subprojects of library project in settings.gradle of main build.
alternatively, can depend on library means of coordinates , deploy library repository mavenlocal(), of course library project not automatically rebuilt if build main project, have manually (vai gradle task) deploy library artifacts.

alternatively can call library build task of type gradlebuild , depend on output of build. library build remains complete own gradle build triggered main build.