Ever wondered how do people maintain different versions of the same app on play store with some customisations in each version. For example, Lite version and a pro version which signify free and paid versions with extra features in paid one.

With the arrival of gradle as a build tool, we got gradle flavors which is an excellent way to have some variations in your app versions.

It can also be leveraged to do hermetic testing with prod/mock flavors. Some other examples could be free/paid flavors and stable/experimental flavors etc.

Now let’s talk about on how to proceed :

The process is very simple

1. Create the flavors in you build.gradle file

android {  
      productFlavors {  
           mock {   
                applicationIdSuffix = ".mock"  
           }  
           prod  
      }  
 }

Here prod and mock are two flavors and the customisations we add are that mock has a applicationIdSuffix. We can also add altogether different applicationIds as well as define a different version for different flavors and a lot of other different things

2. Now we sync the project

If you now open Build Variants tool window either using the quick access menu located in the status bar in the bottom left hand corner of the Android Studio main window or using the Build Variant tool window bar. Once loaded, clicking in the Build Variant cell for the app module should now list the four build variants: mockDebug, mockRelease and prodDebug, prodRelease

After this we get different folders corresponding to the different flavors. We go ahead and add the different folders where we want the changes to occur. For example if I want to show two different maps for two different versions, where one version is for fdroid and another one is for googleplay and hence we replace google maps with OpenStreet Maps in the fdroid version. Hence, We add res/values and res/layout folders for different resources and we also add different java folders and add the classes that would be different for both the flavors. Since both of these will require different set of permissions we can also add AndroidManifest.xml for these were we define the permissions etc. we want.

Not that we only add the changes for each file. All the other essential things can be added from the Main flavor of the android project.

Any variable available through your code

Another thing to know is that the you can have add variables like this so that you can use different variables for different flavors. For examle if you have different api’s and different options for each flavor like if you want to report crashes in one of the flavors and not in other. Here HOST variable is not the only one you can expose in your code. You can do it with whatever you want:

prod {  
    applicationId "zuul.com.android"
    buildConfigField 'String', 'HOST', '"http://api.zuul.com"'
    buildConfigField 'String', 'FLAVOR', '"prod"'
    buildConfigField "boolean", "REPORT_CRASHES", "true"
}

You can access them as follows:

BuildConfig.HOST  
BuildConfig.FLAVOR  
BuildConfig.REPORT_CRASHES

So I think this is a really useful thing to know and is used in almost every app. We all need some configuration differences in our apps and gradle flavors is the best way to go about it. Go nuts with your imagination on the usage of flavors 😛

Adios!