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

Use Firebase for robust analytics and crash reporting.