How to configure extra properties to load in a android app initialization?

Question

I want to setup a variable SERVER_URL and it'll be switched between environments production, test, development.

What I want to do:

@Override
protected void onCreate(Bundle bundle) {
    R.urls.SERVER_URL; // is it a valid approach using resources?
}

Is there a way to switch environments(dev, prod, test) without change the code?

What's the best approach to implement this behavior?

Is there a way to configure it in the playstore my variable(SERVER_URL) or must I implement only in code?

Answer 1

There are 2 ways you can do it:

1/ By string resource like you want

Add a resource file called secret_keys.xml or whatever name to separate it from other resources file. Put your keys, api endpoints here as the normal string resource, remember to add translatable="false" if you don't want to mess with localization.

Place that file in app/debug/res/values/. Create a new debug folder if it doesn't exist. Do the same for staging or release, Android will automatically use the folder with the same name as the build type.

2/ By properties files

Create 3 .properties files and put your keys inside:

HOST="http://api.blablabla.com"
CLIENT_ID="hahaha"
CLIENT_SECRET="hehehe"

Bind it to BuildConfig variable in your app build.gradle, do the same for other build types:

def getPropertiesFile = { path ->
    Properties properties = new Properties()
    properties.load(new FileInputStream(file(path)))
    return properties
}

android {
    ...

    buildTypes {
        debug {
            ...

            getPropertiesFile('./config/development.properties').each { p ->
                buildConfigField 'String', p.key, p.value
            }
        }
        ...
    }
}

In your app just call BuildConfig.HOST to get the string you want

UPDATE

Ignore these config files in .gitignore:

app/config
secret_keys.xml