Android Firebase Skill

Firebase integration patterns: Crashlytics, Analytics, Remote Config, FCM.

When to Use

• Setting up Firebase SDK
• Implementing crash reporting
• Adding analytics events
• Using Remote Config
• Setting up FCM (Push Notifications)

Setup

Dependencies

[versions]
firebase-bom = "33.8.0"

[libraries]
firebase-bom = { module = "com.google.firebase:firebase-bom", version.ref = "firebase-bom" }
firebase-analytics = { module = "com.google.firebase:firebase-analytics-ktx" }
firebase-crashlytics = { module = "com.google.firebase:firebase-crashlytics-ktx" }
firebase-config = { module = "com.google.firebase:firebase-config-ktx" }
firebase-messaging = { module = "com.google.firebase:firebase-messaging-ktx" }

Initialization

// In Application class
FirebaseApp.initializeApp(this)

Crashlytics

// Log non-fatal exception
Firebase.crashlytics.recordException(exception)

// Custom keys for debugging
Firebase.crashlytics.setCustomKey("user_id", userId)
Firebase.crashlytics.setCustomKey("screen", currentScreen)

// Log message
Firebase.crashlytics.log("User clicked purchase button")

// Set user identifier
Firebase.crashlytics.setUserId(userId)

// Force crash (for testing)
throw RuntimeException("Test Crash")

Analytics

// Log standard event
Firebase.analytics.logEvent(FirebaseAnalytics.Event.SELECT_ITEM) {
    param(FirebaseAnalytics.Param.ITEM_ID, itemId)
    param(FirebaseAnalytics.Param.ITEM_NAME, itemName)
}

// Custom event
Firebase.analytics.logEvent("game_completed") {
    param("score", finalScore.toLong())
    param("level", currentLevel.toLong())
    param("time_spent", timeInSeconds.toLong())
}

// Screen tracking
Firebase.analytics.logEvent(FirebaseAnalytics.Event.SCREEN_VIEW) {
    param(FirebaseAnalytics.Param.SCREEN_NAME, screenName)
    param(FirebaseAnalytics.Param.SCREEN_CLASS, screenClass)
}

// User properties
Firebase.analytics.setUserProperty("premium_user", "true")
Firebase.analytics.setUserId(userId)

Remote Config

val remoteConfig = Firebase.remoteConfig
remoteConfig.setConfigSettingsAsync(remoteConfigSettings {
    minimumFetchIntervalInSeconds = 3600 // 1 hour
})

// Set defaults
remoteConfig.setDefaultsAsync(R.xml.remote_config_defaults)

// Fetch and activate
remoteConfig.fetchAndActivate().addOnCompleteListener { task ->
    if (task.isSuccessful) {
        val featureEnabled = remoteConfig.getBoolean("new_feature_enabled")
        val welcomeMessage = remoteConfig.getString("welcome_message")
        val maxRetries = remoteConfig.getLong("max_retries")
    }
}

// Real-time config (auto-update)
remoteConfig.addOnConfigUpdateListener(object : ConfigUpdateListener {
    override fun onUpdate(configUpdate: ConfigUpdate) {
        remoteConfig.activate()
    }
    override fun onError(error: FirebaseRemoteConfigException) {}
})

FCM (Push Notifications)

class MyFirebaseMessagingService : FirebaseMessagingService() {
    override fun onNewToken(token: String) {
        // Send token to server
        sendTokenToServer(token)
    }

    override fun onMessageReceived(message: RemoteMessage) {
        // Handle notification
        message.notification?.let { notification ->
            showNotification(notification.title, notification.body)
        }

        // Handle data payload
        message.data.let { data ->
            handleDataPayload(data)
        }
    }
}

// Get current token
Firebase.messaging.token.addOnCompleteListener { task ->
    if (task.isSuccessful) {
        val token = task.result
    }
}

// Subscribe to topic
Firebase.messaging.subscribeToTopic("news")

Version Compatibility

Firebase BOM	Min SDK	Compile SDK
33.8.0	21	35
33.0.0	21	34
32.0.0	19	33

Error Handling

// Remote Config error handling
remoteConfig.fetchAndActivate()
    .addOnSuccessListener { activated ->
        if (activated) Timber.d("Config activated")
        else Timber.d("Config already up to date")
    }
    .addOnFailureListener { e ->
        when (e) {
            is FirebaseRemoteConfigException ->
                Timber.w("Remote config fetch failed: ${e.code}")
            else -> Timber.e("Unexpected error: ${e.message}")
        }
        // Use cached/default values
    }

// Crashlytics non-fatal reporting
try {
    riskyOperation()
} catch (e: Exception) {
    Firebase.crashlytics.recordException(e)
    // Handle gracefully
}

Troubleshooting

Issue	Solution
Events not showing	Wait 24h or use DebugView
Crashes not reporting	Check google-services.json
FCM not receiving	Verify token registration
Config not updating	Check fetch interval

Security Checklist

• Disable Crashlytics in debug builds (optional)
• No PII in crash logs or analytics
• Validate FCM token before use
• Use App Check for backend protection
• Review analytics data retention settings

Best Practices

• Enable Crashlytics in release builds only
• Use custom events sparingly (500 limit per app)
• Cache Remote Config values locally
• Handle FCM token refresh
• Set user ID consistently across services
• Use DebugView for testing analytics

References

• Firebase Android Setup
• Crashlytics
• Analytics
• Remote Config
• Cloud Messaging

Use Firebase for robust analytics and crash reporting.