productFlavor variables in Android Studio / Gradle

Question

I have an android application that has the following product flavors:

productFlavors {
    local {

    }

    development {


    }

    production {

    }
}

then have the following at the bottom of my build.grade:

File crashlyticsProperties = new File("${project.projectDir.absolutePath}/fabric.properties")
android.applicationVariants.all { variant ->
    def variantSuffix = variant.name.capitalize()
    def generateResourcesTask = project.tasks.getByName("fabricGenerateResources${variantSuffix}")
    def generatePropertiesTask = task("fabricGenerateProperties${variantSuffix}") << {
        Properties properties = new Properties()
        properties.put("apiSecret", WHAT_GOES_HERE)
        properties.put("apiKey", WHAT_GOES_HERE)
        PropertiesUtils.injectPropertyInFile(crashlyticsProperties, properties, "")
    }
    generateResourcesTask.dependsOn generatePropertiesTask
}

I'm trying to set the api secret/key for crashlytics but I need to be able to set these depending on what product flavor I'm building.

properties.put("apiSecret", WHAT_GOES_HERE)
properties.put("apiKey", WHAT_GOES_HERE)

How can I set/get these variables?

Update #1

I've added the following to my build.gradle

productFlavors {
    local {
        buildConfigField "String", "CRASHLYTICS_API_SECRET", "1234"
        buildConfigField "String", "CRASHLYTICS_API_KEY", "1234"
    }

    development {
        buildConfigField "String", "CRASHLYTICS_API_SECRET", "1234"
        buildConfigField "String", "CRASHLYTICS_API_KEY", "1234"
    }

    production {
        buildConfigField "String", "CRASHLYTICS_API_SECRET", "1234"
        buildConfigField "String", "CRASHLYTICS_API_KEY", "1234"
    }
}

Then at the bottom of the build.gradle file I have:

File crashlyticsProperties = new File("${project.projectDir.absolutePath}/fabric.properties")
android.applicationVariants.all { variant ->
    def variantSuffix = variant.name.capitalize()
    def generateResourcesTask = project.tasks.getByName("fabricGenerateResources${variantSuffix}")
    def generatePropertiesTask = task("fabricGenerateProperties${variantSuffix}") << {
        Properties properties = new Properties()
        println "...copying apiSecret for ${variant.name}"
        properties.put("apiSecret", BuildConfig.CRASHLYTICS_API_SECRET)
        println "...copying apiKey for ${variant.name}"
        properties.put("apiKey", BuildConfig.CRASHLYTICS_API_KEY)
        PropertiesUtils.injectPropertyInFile(crashlyticsProperties, properties, "")
    }
    generateResourcesTask.dependsOn generatePropertiesTask
}

This however does not compile and gives me:

Error:(334, 1) Execution failed for task ':app:fabricGeneratePropertiesDevelopmentDebug'. Could not find property 'BuildConfig' on task ':app:fabricGeneratePropertiesDevelopmentDebug'.

Answer 1

For this error:

Error:(334, 1) Execution failed for task ':app:fabricGeneratePropertiesDevelopmentDebug'. Could not find property 'BuildConfig' on task ':app:fabricGeneratePropertiesDevelopmentDebug'.

Use a different construction, eg:

variant.mergedFlavor.buildConfigFields["CRASHLYTICS_API_SECRET"].value

Of course this solution expects, that such BuildConfig field is defined. If you expect field would not exist, make sure to check if present first.

EDIT:

If you'd like a solution described in your question:

File crashlyticsProperties = new File("${project.projectDir.absolutePath}/fabric.properties")
android.applicationVariants.all { variant ->
    def variantSuffix = variant.name.capitalize()
    def generateResourcesTask = project.tasks.getByName("fabricGenerateResources${variantSuffix}")
    def generatePropertiesTask = task("fabricGenerateProperties${variantSuffix}") << {
        Properties properties = new Properties()
        println "...copying apiSecret for ${variant.name}"
        properties.put("apiSecret", variant.mergedFlavor.buildConfigFields.get("CRASHLYTICS_API_SECRET").value)
        println "...copying apiKey for ${variant.name}"
        properties.put("apiKey", variant.mergedFlavor.buildConfigFields.get("CRASHLYTICS_API_KEY").value)
        PropertiesUtils.injectPropertyInFile(crashlyticsProperties, properties, "")
    }
    generateResourcesTask.dependsOn generatePropertiesTask
}

Answer 2

you can have different buildConfigFields for every flavour where you can declare mutiple strings variables and seperate keys for each flavour easily

Like :

local { buildConfigField "String", "KEY", '"abcKey' } 
development { buildConfigField "String", "KEY", '"xyzKey' } 

and use these variables in your java files as follows

properties.put("apiSecret", BuildConfig.KEY)