Set constant value with gradle

Question

I just moved to the android gradle build system and it is not clear for me how to set constant values.

e.g. I have

API.java which contains

BASE_URL = "http://debug.server.com"

but when gradle builds release I need BASE_URL to be "http://release.server.com"

How to replace this value at the build time?

Answer 1

Gradle generates a class called BuildConfig which contains static members (such as the boolean DEBUG, which is set to true for debug variants).

You could either query this in java like so:

if (BuildConfig.DEBUG) {
    BASE_URL = "http://debug.server.com"
} else {
    BASE_URL = "http://release.server.com"
}

or the same thing as a one-liner:

BASE_URL = BuildConfig.DEBUG ? "http://debug.server.com" : "http://release.server.com"

---

OR

You could actually set the BASE_URL inside the the BuildConfig class using gradle like so:

android {
    buildTypes {
        debug {
            buildConfigField "String", "BASE_URL", '"http://debug.server.com"'
        }

        release {
            buildConfigField "String", "BASE_URL", '"http://release.server.com"'
        }
    }
}

Note the single and double quotations around the value in gradle, as others have mentioned in the comments. This way, the double quotes become part of the value.

As a result, the static reference BuildConfig.BASE_URL would point to the corresponding URL (i.e. "debug.server.com" for debug, "release.server.com" for release)

Answer 2

Answer of fifer-sheep is correct. Just wanted to leave a solution for more than two environments.

Two flavors for staging and live.

productFlavors {
    staging {
        ...
    }
    production {
        ...
    }
}

Whole app config relies on the current ENV. Using:

public static String ENV_DEVELOPMENT = "development";
public static String ENV_STAGING = "staging";
public static String ENV_PRODUCTION = "production";

ENV = BuildConfig.DEBUG ? ENV_DEVELOPMENT : BuildConfig.FLAVOR;

I can switch between all different ENVs while testing locally but force staging/live settings if released.