如何在gradle中过滤子模块以应用适当的插件？

Question

I have a multi-module project of which some are Java libraries and others Android libraries. I wanted to apply custom plugins for my sub projects (modules) depending on the project type, so I have done something like this (see below code snippet) in my project root's build.gradle file. This setup is working but I'm wondering if there is any other way of doing it. Gradle suggests Filtering by properties but I get the error Cannot add task 'integTest' as a task with that name already exists if I try that. The integTest is a task I created in customJavaBuild.gradle and customAndroidBuild.gradle files. Any help is appreciated. Thanks!

def javaLibraries = ["projA", "projB"]
def androidLibraries = ["projC"]

subprojects {
    if (javaLibraries.contains(it.name)) {
        apply from: '$rootDir/gradle/customJavaBuild.gradle'
    } else if (androidLibraries.contains(it.name)) {
        apply from: '$rootDir/gradle/customAndroidBuild.gradle'
    } else {
        //Apply custom plugin for some other project type.
    }
} 

Filtering by properties

subprojects {
    project.ext {
        projectType = null
    }

    project.afterEvaluate {
        if (project.ext.projectType == 'jar') {
            apply from: '$rootDir/gradle/customJavaBuild.gradle'
        } else if (project.ext.projectType == 'aar') {
            apply from: '$rootDir/gradle/customAndroidBuild.gradle'
        } else {
            //Apply custom plugin for some other project type.
        }
    }
}

And I have this extra property ext.projectType = 'jar' in my sub-modules' (projA, projB, projC) build.gradle files.

Answer 1

The problem is that in your project.afterEvaluate block you are applying your custom gradle script to the root project and not to the evaluated sub project , which causes the error with integTest task already defined.

You should rewrite your project.afterEvaluate block with something similar to the following:

subprojects {
    project.ext {
        projectType = null
    }

    project.afterEvaluate {
        if (project.ext.projectType == 'jar') {
            // WARNING : use "project.apply ..." instead of "apply ..." here
            project.apply from : "$rootDir/gradle/customJavaBuild.gradle"
        } else if (project.ext.projectType == 'aar') {
            project.apply from : "$rootDir/gradle/customAndroidBuild.gradle"
        } else {
            // nothing
        }
    }

}