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Gradle Tasks: Export an Android native plugin into Unity with gradle

By tomazsaraiva

On March 17, 2017

At 1:11 am

In Article

2865 Views

I’m developing some Android Native Plugins for Unity and decided to implement some Gradle Tasks to export the plugin into Unity as a .jar, .aar or a library android project.

Each native functionality is in a separate android module, as you can see in the picture. IMHO, this way it’s possible to import only the necessary modules into each project and it’s also easier to test, maintain and update (I would appreciate your input about this question).

I needed a Gradle Task that could be written once and used on each module as necessary. So all my tasks are inside the build.gradle file for the entire project.

This is the build.gradle file on the project root. You also have build.gradle files for each individual module.

Here is the complete build.gradle file. Next, we’ll see how to use it.

Gradle Tasks



// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.3'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

// MY GRADLE TASKS
subprojects {

    // path to Assets folder of the Unity Project
    String unityAssetsDir = "${rootDir.getPath()}/../addcomponent-native-unity/Assets/";

    // path to the specific directory inside the Assets folder
    String unityTargetDir = unityAssetsDir + "Plugins/Android/";

    // how to call the tasks group on the Gradle View
    String taskGroupName = "plugins";

    // the current build type, right now it has no difference: debug; release
    String buildType = "debug";


    /***** .JAR *****/

    task exportJAR(dependsOn: "assemble" + buildType.capitalize(), type: Copy, group: taskGroupName) {

        // where the .jar file is located when we build the module
        String sourceDir = "${buildDir.getPath()}/intermediates/bundles/" + buildType + "/";

        // how the .jar file is called when we build the module
        String sourceFilename = "classes.jar";

        // how we want to call the .jar file when importing into Unity
        String targetFilename = "addcomponent-${project.name}.jar";

        // copy the .jar file into the Unity folder
        // include the .jar file and rename it
        from(sourceDir)
        into(unityTargetDir)
        include(sourceFilename)
        rename(sourceFilename, targetFilename)
    }


    /***** .AAR *****/

    task exportAAR(dependsOn: "assemble" + buildType.capitalize(), type: Copy, group: taskGroupName) {

        // where the .aar file is located when we build the module
        String sourceDir = "${buildDir.getPath()}/outputs/aar/";

        // how the .aar file is called when we build the module
        String sourceFilename = "${project.name}-" + buildType + ".aar";

        // how we want to call the .aar file when importing into Unity
        String targetFilename = "addcomponent-${project.name}.aar";

        // copy the .aar file into the Unity folder
        // include the .aar file and rename it
        from(sourceDir)
        into(unityTargetDir)
        include(sourceFilename)
        rename(sourceFilename, targetFilename)
    }

    /***** LIBRARY PROJECT *****/

    // this task creates a necessary project.properties file so that Unity recognizes the folder
    // as a library android project
    task createProperties() &lt;&lt; {

        // project.properties path
        String properties = unityTargetDir + "addcomponent-${project.name}/" + "project.properties";

        // creates the file
        def file = new File(properties);
        file.createNewFile();
    }

    task exportLibrary(dependsOn: ["assemble" + buildType.capitalize()], type: Copy, group: taskGroupName) {

        // where the .jar file is located when we build the module
        String sourceDir = "${buildDir.getPath()}/intermediates/bundles/" + buildType + "/";

        // the res folder
        String resources = "res/";

        // the manifest filename
        String manifest = "AndroidManifest.xml";

        // copy the jar file,
        // include the res folder and the AndroidManitest.xml
        // place the jar file inside a /libs folder
        from(sourceDir)
        into(unityTargetDir + "addcomponent-${project.name}/")
        include(resources, manifest, 'classes.jar')
        rename('classes.jar', 'libs/classes.jar')
    }

    // run the create properties task at the end
    exportLibrary.finalizedBy createProperties
}

// END OF MY GRADLE TASKS


task clean(type: Delete) {
    delete rootProject.buildDir
}

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// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {

repositories {

jcenter()

}

dependencies {

classpath 'com.android.tools.build:gradle:2.2.3'

// NOTE: Do not place your application dependencies here; they belong

// in the individual module build.gradle files

}

allprojects {

repositories {

jcenter()

}

// MY GRADLE TASKS

subprojects {

// path to Assets folder of the Unity Project

String unityAssetsDir = "${rootDir.getPath()}/../addcomponent-native-unity/Assets/";

// path to the specific directory inside the Assets folder

String unityTargetDir = unityAssetsDir + "Plugins/Android/";

// how to call the tasks group on the Gradle View

String taskGroupName = "plugins";

// the current build type, right now it has no difference: debug; release

String buildType = "debug";

/***** .JAR *****/

task exportJAR(dependsOn: "assemble" + buildType.capitalize(), type: Copy, group: taskGroupName) {

// where the .jar file is located when we build the module

String sourceDir = "${buildDir.getPath()}/intermediates/bundles/" + buildType + "/";

// how the .jar file is called when we build the module

String sourceFilename = "classes.jar";

// how we want to call the .jar file when importing into Unity

String targetFilename = "addcomponent-${project.name}.jar";

// copy the .jar file into the Unity folder

// include the .jar file and rename it

from(sourceDir)

into(unityTargetDir)

include(sourceFilename)

rename(sourceFilename, targetFilename)

}

/***** .AAR *****/

task exportAAR(dependsOn: "assemble" + buildType.capitalize(), type: Copy, group: taskGroupName) {

// where the .aar file is located when we build the module

String sourceDir = "${buildDir.getPath()}/outputs/aar/";

// how the .aar file is called when we build the module

String sourceFilename = "${project.name}-" + buildType + ".aar";

// how we want to call the .aar file when importing into Unity

String targetFilename = "addcomponent-${project.name}.aar";

// copy the .aar file into the Unity folder

// include the .aar file and rename it

from(sourceDir)

into(unityTargetDir)

include(sourceFilename)

rename(sourceFilename, targetFilename)

}

/***** LIBRARY PROJECT *****/

// this task creates a necessary project.properties file so that Unity recognizes the folder

// as a library android project

task createProperties() << {

// project.properties path

String properties = unityTargetDir + "addcomponent-${project.name}/" + "project.properties";

// creates the file

def file = new File(properties);

file.createNewFile();

}

task exportLibrary(dependsOn: ["assemble" + buildType.capitalize()], type: Copy, group: taskGroupName) {

// where the .jar file is located when we build the module

String sourceDir = "${buildDir.getPath()}/intermediates/bundles/" + buildType + "/";

// the res folder

String resources = "res/";

// the manifest filename

String manifest = "AndroidManifest.xml";

// copy the jar file,

// include the res folder and the AndroidManitest.xml

// place the jar file inside a /libs folder

from(sourceDir)

into(unityTargetDir + "addcomponent-${project.name}/")

include(resources, manifest, 'classes.jar')

rename('classes.jar', 'libs/classes.jar')

}

// run the create properties task at the end

exportLibrary.finalizedBy createProperties

}

// END OF MY GRADLE TASKS

task clean(type: Delete) {

delete rootProject.buildDir

}

The easiest way to use the new Gradle Tasks is selecting them on the Gradle Window.

Open the Gradle window on the right side of the screen or if it’s not present open it by selecting View – Tool Windows – Gradle.

Each one of the modules will have a group called plugins with the three tasks inside, exportAAR, exportJAR and exportLibrary. You can double-click on the task name to run it.

However, this will run the selected task on all modules!

This is not the intended behaviour when trying to export a single module into the desired project. So far, I was not able to understand why it happens when using the gradle window. So I’ve decided to run the tasks using the Terminal window.

Open the Terminal on the bottom of the screen or if it’s not present open it by selecting the View – Tool Windows – Terminal.

To run a task for a single module type the following:

./gradlew <modulename>:<taskname>

If the task succeeds you will have a BUILD SUCCESSFUL message on the Terminal Window.

Just as an example, the next image is the result when you export the same module using all the different tasks.

You need to choose only one of the methods when exporting your module.

To know more about Android Native Plugins, check my previous tutorial on the subject and to get really deep into it, I highly recommend this great tutorial by eppz.

I will post a later article on building each one of this modules and on building a Unity Project including plugins and resolving dependencies issues, merging manifests, using the Google Play Resolver, etc (I’m still fighting with all this).

Stay tuned 🙂

Happy Coding