Declare/use variable in gradle file - use it in java

Question

I have in my gradle file something like :

String packageName = com.test.free

I want this String variable packageName to use in my java class. I use Android Studio 1.5.1.

Is it possible? How can I transfer this String from gradle to java ?

I have read similar questions here but none of the solutions worked.

Gavriel · Answer 1 · 2016-01-27T19:00:35.417

2

Create a gradle task that writes packageName into a java file like:

build.gradle:

task generateGradleValuesJava {
    def java = 
      'public class GradleValues {' +
      '  public static String packageName = "' + project.packageName+ '";' +
      '  }' +
      '}'
    def javaFile = new File('GradleValues.java')
    javaFile.write(java)
}

compileJava.dependsOn generateGradleValuesJava

Compile this file into your jar and use it:

GradleValues.packageName

edited Jan 27 '16 at 19:00

answered Jan 27 '16 at 18:50

Gavriel

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I think I understand it now. I`l try this. – Adrian Ivasku Jan 27 '16 at 19:13

CommonsWare · Accepted Answer · 2016-01-27T19:18:09.233

2

If that value is really your applicationId, that is already available to you as BuildConfig.APPLICATION_ID.

Otherwise, you can add your own custom fields to BuildConfig. These can include dynamic values:

import static java.util.UUID.randomUUID

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "com.commonsware.myapplication"
        minSdkVersion 21
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }

    buildTypes {
        debug {
            buildConfigField "String", "FOO", '"'+randomUUID()+'"'
        } 

        release {
            buildConfigField "String", "FOO", '"a49f05b4-f55a-4066-a107-9098c9350f43"'
        }
    }
}

edited Jan 27 '16 at 19:18

answered Jan 27 '16 at 18:50

CommonsWare

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No. I have given that value as an example. I have some other data I need to access. – Adrian Ivasku Jan 27 '16 at 18:53
BuildConfig I can`t use because the accessed value must be hardcoded. The Value I am reading is dynamic and I am reading it from a String. Is there something like when transferin java String value to native via jni bridge? – Adrian Ivasku Jan 27 '16 at 19:05
@AdrianIvasku: "because the accessed value must be hardcoded" -- I don't think so. It has to be properly formatted (e.g., wrap a string value in quotes), but AFAIK it can be generated dynamically via a Groovy expression. "Is there something like when transferin java String value to native via jni bridge?" -- no, for the simple reason that Gradle and Groovy are not on the Android device. – CommonsWare Jan 27 '16 at 19:11
@AdrianIvasku: See the updated answer for an example of a dynamically-generated value. – CommonsWare Jan 27 '16 at 19:18
It works! Maybe Gavriel`s solution is correct too, but I have a confirmation for this one. My fault, I haven`t mentioned that I use experimental gradle so my solution is like this : buildConfigFields.with { create() { type = "String" name = "packageName" value = '"'+packageName+'"' } } And then call it from java BuildConfig.packageName. Thank you ! – Adrian Ivasku Jan 27 '16 at 20:38

Declare/use variable in gradle file - use it in java

2 Answers2