Android - Read build.gradle properties inside class

Question

I would like to have access to build.gradle properties so I can automatize some processes in my app.

This is the structure i have at the moment:

rootProject/build.gradle

buildscript {
    ext {
        buildTools = "25.0.2"
        minSdk = 16
        compileSdk = 23
        targetSdk = 23

        versions = [supportLib         : '25.0.0',
                    multidex           : '1.0.1',
                    playServices       : '10.0.1']
        libs = [appcompat            : "com.android.support:appcompat-v7:$versions.supportLib",
               design               : "com.android.support:design:$versions.supportLib"]

        .... Other libraries and setup....

    }
}

rootProject/app/build.gradle

...
dependencies {
    // Support libraries
    compile libs.appcompat
    compile libs.design
    .....
}

I would like to access both on Java and build.gradle side the properties version and libs variables. How can I achieve this?

https://stackoverflow.com/questions/17197636/is-it-possible-to-declare-a-variable-in-gradle-usable-in-java — Murat Karagöz, Aug 09 '17 at 09:38
[This answer](https://stackoverflow.com/a/42130853/1083957) will be helpful. — azizbekian, Aug 09 '17 at 09:47

score 12 · Accepted Answer · answered Aug 10 '17 at 06:26

You can do somenthing like this, but outside the buildscript block

ext {
    // Version
    supportVersion = '26.0.0'

    // Support Libraries dependencies
    supportDependencies = [
            design:            "com.android.support:design:${supportVersion}",
            recyclerView:      "com.android.support:recyclerview-v7:${supportVersion}",
            cardView:          "com.android.support:cardview-v7:${supportVersion}",
            appCompat:         "com.android.support:appcompat-v7:${supportVersion}",
            supportAnnotation: "com.android.support:support-annotations:${supportVersion}",
    ]

    firebaseVersion = '11.0.2';

    firebaseDependencies = [
            core:         "com.google.firebase:firebase-core:${firebaseVersion}",
            database:     "com.google.firebase:firebase-database:${firebaseVersion}",
            storage:      "com.google.firebase:firebase-storage:${firebaseVersion}",
            crash:        "com.google.firebase:firebase-crash:${firebaseVersion}",
            auth:         "com.google.firebase:firebase-auth:${firebaseVersion}",
            messaging:    "com.google.firebase:firebase-messaging:${firebaseVersion}",
            remoteConfig: "com.google.firebase:firebase-config:${firebaseVersion}",
            invites:      "com.google.firebase:firebase-invites:${firebaseVersion}",
            adMod:        "com.google.firebase:firebase-ads:${firebaseVersion}",
            appIndexing:  "com.google.android.gms:play-services-appindexing:${firebaseVersion}",
    ];
}


// Module build file
dependencies {
    // ...
    compile supportDependencies.appCompat
    compile supportDependencies.design
    compile firebaseDependencies.crash
}

In java you can't access the build.gradle files since they are used only at buildtime. Hovewer you can put same values in the BuildConfig file. In this file there are some prebuilt values like BuildConfig.VERSION_NAME or you can use some custom keys like:

android {
    ...
    defaultConfig {
        ...
        // defining the build date
        buildConfigField "long", "BUILD_DATE", System.currentTimeMillis() + "L"
        // define whether this build is a production build
        buildConfigField "boolean", "IS_PRODUCTION", "false"
        // note that to define a string you need to escape it
        buildConfigField "String", "API_KEY", "\"my_api_key\""
    }
}

The automatically-generated <package_name>.BuildConfig.java will contain the following fields based on the directive above:

public class BuildConfig {
    // ... other generated fields ...
    public static final long BUILD_DATE = 1469504547000L;
    public static final boolean IS_PRODUCTION = false;
    public static final String API_KEY = "my_api_key";
}

Nice code. In this case i can't still share 'firebaseDependencies' map (for example) between build.gradle and Android. — Bugdr0id, Aug 10 '17 at 09:53
@Bugdr0id No, you can't share maps or variables between gradle and Android. The only way is to use buildConfigField to add all the info in the class used by Android code. — Gabriele Mariotti, Aug 10 '17 at 15:53
@GabrieleMariotti How can I read `firebaseVersion` in my java class, your help will be appreciated — HAXM, Jan 28 '19 at 16:52
Don't forget to CLEAN YOUR PROJECT. I had a hard time, then it worked after cleaning. — YoussefDir, Oct 11 '20 at 19:12

smora · Answer 2 · 2017-08-09T10:58:47.927

7

Use gradle.properties file to define your values in one only place, then you can use this values in your gradle project config.

Then to be able to access thoses values in Java android code use 'buildConfigField' definition.

gradle.properties

values=value1,value2

build.gradle

def String[] valuesArray = values.split(',')

android {
    defaultConfig {
        buildConfigField "String[]", "VALUES_ARRAY", "{" +
                "\"" + valuesArray[0] + "\"," +
                "\"" + valuesArray[1] + "\"" +
                "}"
    }
}

in java file

BuildConfig.VALUES_ARRAY

edited Aug 09 '17 at 10:58

answered Aug 09 '17 at 09:38

smora

717
5
18

With 'buildConfigField' Im able to declare a variable to be used by BuildConfig, but how can I reuse those same values in build.gradle? I would like to declare an array which can be accessed by gradle.build and Java. – Bugdr0id Aug 09 '17 at 10:11
@Bugdr0id define variable in gradle and use variable in buildConfigField – DeKaNszn Aug 09 '17 at 10:23
@DeKaNszn can you propose some code? (as an answer maybe) – Bugdr0id Aug 09 '17 at 10:25
Maybe you can edit your question with your specific "array" need. – smora Aug 09 '17 at 11:01
@Bugdr0id I've fixed answer from MoraS. – DeKaNszn Aug 09 '17 at 11:17

Android - Read build.gradle properties inside class

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