How to set up Feature Flags in Android (Kotlin)

To implement feature flags in an Android app using the Statsig SDK, follow these steps, including creating a basic "Hello World" Android app, integrating Statsig, and managing feature flags in the Statsig console.

Step 1: Create a Basic Android "Hello World" App

1. Install Android Studio:

   • Download and install Android Studio from the official website. Launch it and follow the setup wizard to install any necessary SDK packages.

2. Start a New Android Studio Project:

   • Open Android Studio and choose to start a new Android project.
   • Select the "Empty Activity" template and click "Next".
   • Enter your Application name, for example, "HelloWorldApp", and choose a save location.
   • Make sure to select Kotlin as the language and the minimum API level supported by your app. API level 21 (Android 5.0 Lollipop) is a good starting point for broad compatibility.
   • Click "Finish" to create your project.

3. Modify MainActivity.kt:

   • Open MainActivity.kt and ensure it contains code similar to the following for a basic "Hello World" setup:

     package com.example.helloworldapp
     
     import androidx.appcompat.app.AppCompatActivity
     import android.os.Bundle
     import android.widget.TextView
     
     class MainActivity : AppCompatActivity() {
         override fun onCreate(savedInstanceState: Bundle?) {
             super.onCreate(savedInstanceState)
             setContentView(R.layout.activity_main)
     
             val textView: TextView = findViewById(R.id.textView)
             textView.text = "Hello, World!"
         }
     }

4. Update the Layout:

   • Ensure res/layout/activity_main.xml is updated to include a TextView with @+id/textView.

Step 2: Integrating Statsig for Feature Flags

1. Add Statsig SDK Dependency:

   • Open your app's build.gradle (Module: app) file, and add the Statsig SDK dependency to the dependencies block:

     implementation 'com.statsig:android-sdk:1.+'

2. Initialize Statsig in Your Application:

   • Modify MainActivity.kt to initialize Statsig and check a feature flag:

     import androidx.appcompat.app.AppCompatActivity
     import android.os.Bundle
     import android.widget.TextView
     import com.statsig.androidsdk.Statsig
     import com.statsig.androidsdk.StatsigOptions
     
     class MainActivity : AppCompatActivity() {
     
         override fun onCreate(savedInstanceState: Bundle?) {
             super.onCreate(savedInstanceState)
             setContentView(R.layout.activity_main)
     
             // Initialize Statsig
             Statsig.initialize(
                 this.applicationContext,
                 "client-sdk-key",
                 options = StatsigOptions(initTimeoutMs = 6000)
             ) {
                 // Check if a feature flag is enabled
                 val isFeatureEnabled = Statsig.checkGate("example_feature_flag")
                 runOnUiThread {
                     val textView: TextView = findViewById(R.id.textView)
                     if (isFeatureEnabled) {
                         textView.text = "Feature Enabled!"
                     } else {
                         textView.text = "Hello, World!"
                     }
                 }
             }
         }
     
         override fun onDestroy() {
             super.onDestroy()
             Statsig.shutdown()
         }
     }

   • Replace "client-sdk-key" with your actual Statsig Client SDK Key.

   • Replace "example_feature_flag" with the name of the feature flag you will create.

Step 3: Creating Feature Flags in the Statsig Console

1. Sign Up/Login to Statsig:

   • Visit Statsig's website and create an account or log in.

2. Create a New Project:

   • In the Statsig console, create a new project for your application.

3. Navigate to Feature Flags:

   • Access the "Feature Flags" section from the dashboard.

4. Create a New Feature Flag:

   • Click "Create Feature Flag".
   • Enter a name for your feature flag (e.g., example_feature_flag).
   • Configure targeting rules as needed.
   • Save your feature flag.

   

5. Toggle Your Feature Flag:

   • You can enable or disable your feature flag from the dashboard and configure it as needed.

This guide outlines creating a simple Android app, integrating Statsig for feature management, and setting up feature flags in the Statsig console. Ensure your client-sdk-key is the client (not server) key meant for client-side use, and always manage feature flags responsibly to provide the best user experience.