How to use a variable for android section of build.gradle?

Question

Based on this answer, I realized that we can use Gradle variables (I'm not familiar with Gradle of course, so excuse my terminology) to make some consistencies across many Android projects.

For example, I want to change the android closure configuration from this:

android {
    compileSdkVersion 27
    buildToolsVersion '27.0.3'
    defaultConfig {
        minSdkVersion 16
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
    }
}

To this:

android {
    compileSdkVersion configurationVariables.sdk
    buildToolsVersion configurationVariables.buildToolsVersion    
  defaultConfig {
        minSdkVersion configurationVariables.minSdk
        targetSdkVersion configurationVariables.targetSdk
        versionCode 1
        versionName "1.0"
    }
}

However, I get this error:

Error:(5, 0) startup failed: build file 'path_to_android\build.gradle': 5: Statement labels may not be used in build scripts. In case you tried to configure a property named 'buildToolsVersion', replace ':' with '=' or ' ', otherwise it will not have the desired effect. @ line 5, column 24. buildToolsVersion: configurationVariables.buildToolsVersion

How can I use variables to centralize my build configuration across projects and modules?

Update: I'm defining my configurationVariables as follow:

ext {

    configurationVariables = [
            sdk = 27,
            buildToolsVersion = "27.0.3",
            minSdk = 16,
            targetSdk = 27
    ]
}

I write this in a config.gradle file and use apply from to import it in the build.gradle of the root project to apply it on all subprojects.

Answer 1

your config file structure store value as a varible. Generally this structure is use to store variable.Your config file should be like this

ext {


        sdk = 27
        buildToolsVersion = "27.0.3"
        minSdk = 16
        targetSdk = 27

}

and you use this variable as

compileSdkVersion sdk buildToolsVersion buildToolsVersion

I haven't use array for storing this variable but as you given in another answer link they store array variable with colon(:) and you are directly storing values. I am not sure but try to use colon like this if you want to use an array :

ext {
configurationVariables = [
        sdk : 27,
        buildToolsVersion : "27.0.0",
        minSdk : 16,
        targetSdk : 27
]
}