Firebase Analytics in Android Kotlin - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ ui_behavior

intermediate

Logging a Custom Event with Parameters

You want to log a custom event named "purchase_complete" with parameters item_id and price using Firebase Analytics in Kotlin. Which code snippet correctly logs this event?

Android Kotlin

val analytics = Firebase.analytics
// Log event here

A

analytics.logEvent("purchase_complete") {
  param("item_id", "sku123")
  param("price", 9.99)
}

B analytics.logEvent("purchase_complete", mapOf("item_id" to "sku123", "price" to 9.99))

C

val bundle = Bundle().apply {
  putString("item_id", "sku123")
  putDouble("price", 9.99)
}
analytics.logEvent("purchase_complete", bundle)

D analytics.logEvent("purchase_complete", Bundle().putString("item_id", "sku123"))

💡 Hint

Remember that Firebase Analytics expects a Bundle object for event parameters in Kotlin.

Firebase Analytics in Kotlin requires event parameters to be passed as a Bundle object. Option C correctly creates a Bundle with the parameters and logs the event. Option C uses a Kotlin DSL style which is not supported. Option C tries to pass a Map which is invalid. Option C passes a Bundle but only with one parameter and incorrectly chains putString without storing the Bundle.

❓ lifecycle

intermediate

When to Initialize Firebase Analytics

In an Android app using Kotlin, where is the best place to initialize Firebase Analytics to ensure it is ready for logging events throughout the app?

A In the <code>Application</code> class <code>onCreate()</code> method

B Inside the <code>onCreate()</code> method of the main <code>Activity</code>

C Inside the <code>onStart()</code> method of every <code>Activity</code>

D Right before logging each event

💡 Hint

Think about initializing once for the whole app lifecycle.

Initializing Firebase Analytics in the Application class's onCreate() method ensures it is set up once when the app starts and is available throughout the app lifecycle. Initializing in each Activity or before each event is inefficient and error-prone.

📝 Syntax

advanced

Correct Syntax for Setting User Property

Which Kotlin code snippet correctly sets a user property named "favorite_genre" with value "sci-fi" using Firebase Analytics?

Android Kotlin

val analytics = Firebase.analytics
// Set user property here

A analytics.setUserProperty("favorite_genre", value = "sci-fi")

B analytics.setUserProperty("favorite_genre", "sci-fi")

C analytics.setUserProperty("favorite_genre" to "sci-fi")

D analytics.setUserProperty(name = "favorite_genre", "sci-fi")

💡 Hint

Check the method signature for setUserProperty in Firebase Analytics Kotlin API.

The correct method call is setUserProperty(name: String, value: String?). Option B matches this signature. Option B uses a Pair which is invalid. Option B uses a named argument 'value' which is allowed but the method signature does not define a named parameter 'value' explicitly, so it may cause an error. Option B mixes named and positional arguments incorrectly.

❓ navigation

advanced

Tracking Screen Views Correctly

You want to track screen views in your Android app using Firebase Analytics. Which approach correctly logs the screen name "HomeScreen" when the user navigates to it?

A analytics.setCurrentScreen(this, "HomeScreen", "MainActivity")

B

analytics.logEvent(FirebaseAnalytics.Event.SCREEN_VIEW) {
  param(FirebaseAnalytics.Param.SCREEN_NAME, "HomeScreen")
}

C

analytics.logEvent("screen_view", Bundle().apply {
  putString("screen_name", "HomeScreen")
})

D analytics.setCurrentScreen(this, "HomeScreen", null)

💡 Hint

Check the official Firebase method for setting current screen with activity context.

Option A correctly calls setCurrentScreen with the activity context, screen name, and screen class override. Option A is deprecated and may cause runtime errors. Option A uses a Kotlin DSL style which is not supported. Option A logs a custom event but does not set the current screen properly.

🔧 Debug

expert

Diagnosing Missing Analytics Events

You notice that some custom events are not appearing in Firebase Analytics dashboard after logging them in your Kotlin app. Which of the following is the MOST likely cause?

A You did not call <code>FirebaseApp.initializeApp(context)</code> explicitly in your Application class

B You logged events before initializing Firebase Analytics instance

C You forgot to add the Firebase Analytics dependency in your build.gradle file

D You used event names longer than 40 characters or with invalid characters

💡 Hint

Firebase Analytics enforces naming rules for events.

Firebase Analytics requires event names to be 40 characters or less and only contain alphanumeric characters and underscores. Using invalid event names causes events to be dropped silently. Option D would cause compile errors. Option D usually causes runtime errors. Option D is not required if Firebase is configured properly via google-services plugin.

Practice

1. What is the main purpose of Firebase Analytics in an Android app?

easy

A. To manage app permissions

B. To store user passwords securely

C. To create user interface layouts

D. To track user actions and events within the app

Solution

1. Step 1: Understand Firebase Analytics role

   Firebase Analytics is designed to collect data about user interactions and events in the app.

2. Step 2: Compare options with purpose

   Only To track user actions and events within the app describes tracking user actions, which matches Firebase Analytics' main use.

3. Final Answer:

   To track user actions and events within the app -> Option D

4. Quick Check:

   Firebase Analytics tracks user actions = A [OK]

Hint: Firebase Analytics tracks events and user behavior [OK]

Common Mistakes:

• Confusing analytics with security or UI tasks
• Thinking it manages app permissions
• Assuming it stores sensitive data like passwords

2. Which is the correct Kotlin syntax to log a custom event named purchase with Firebase Analytics?

easy

A. firebaseAnalytics.logEvent("purchase", Bundle())

B. firebaseAnalytics.logEvent(purchase, null)

C. firebaseAnalytics.logEvent("purchase")

D. firebaseAnalytics.logEvent('purchase', null)

Solution

1. Step 1: Recall logEvent method signature

   logEvent requires event name as String and a Bundle for parameters (can be empty).

2. Step 2: Check options for correct syntax

   firebaseAnalytics.logEvent("purchase", Bundle()) uses a String event name and an empty Bundle(), which is valid Kotlin syntax.

3. Final Answer:

   firebaseAnalytics.logEvent("purchase", Bundle()) -> Option A

4. Quick Check:

   logEvent needs event name string and Bundle = D [OK]

Hint: Use event name as string and Bundle() for parameters [OK]

Common Mistakes:

• Omitting quotes around event name
• Passing null instead of Bundle()
• Calling logEvent with only one argument

3. Given this Kotlin code snippet, what will be logged as the event name?

val bundle = Bundle()
bundle.putString("item", "book")
firebaseAnalytics.logEvent("select_content", bundle)

medium

A. "item"

B. "select_content"

C. "book"

D. No event will be logged

Solution

1. Step 1: Identify event name argument

   The first argument to logEvent is the event name string "select_content".

2. Step 2: Understand bundle role

   The bundle contains parameters, here "item" with value "book", but event name is separate.

3. Final Answer:

   "select_content" -> Option B

4. Quick Check:

   Event name is first argument = C [OK]

Hint: Event name is first string argument in logEvent [OK]

Common Mistakes:

• Confusing parameter keys with event name
• Thinking bundle keys become event names
• Assuming no event logs without explicit call

4. What is wrong with this Kotlin code for logging an event?

val bundle = Bundle()
bundle.putString("level", "5")
firebaseAnalytics.logEvent(level, bundle)

medium

A. The variable 'level' is not defined as a String event name

B. Bundle cannot contain strings

C. logEvent requires only one argument

D. Bundle should be null instead of a Bundle object

Solution

1. Step 1: Check event name argument

   logEvent expects a String event name, but 'level' is used as a variable, which is undefined here.

2. Step 2: Validate bundle usage

   Bundle usage is correct; it can contain strings and is passed properly.

3. Final Answer:

   The variable 'level' is not defined as a String event name -> Option A

4. Quick Check:

   Event name must be a string literal or defined string = B [OK]

Hint: Event name must be a string, not an undefined variable [OK]

Common Mistakes:

• Passing undefined variables as event names
• Misunderstanding Bundle contents
• Using wrong number of arguments in logEvent

5. You want to log a purchase event with item name and price using Firebase Analytics in Kotlin. Which code correctly logs this event with parameters?

hard

A. val bundle = Bundle()
bundle.putString("item_name", "shoes")
bundle.putDouble("price", "59.99")
firebaseAnalytics.logEvent("purchase", bundle)

B. val bundle = Bundle()
bundle.putString("item_name", "shoes")
bundle.putFloat("price", "59.99f")
firebaseAnalytics.logEvent("purchase", bundle)

C. val bundle = Bundle()
bundle.putString("item_name", "shoes")
bundle.putString("price", "59.99")
firebaseAnalytics.logEvent("purchase", bundle)

D. val bundle = Bundle()
bundle.putInt("item_name", 59)
bundle.putDouble("price", 59.99)
firebaseAnalytics.logEvent("purchase", bundle)

Solution

1. Step 1: Check parameter types for Firebase Analytics

   Firebase Analytics Bundle supports putString for strings; price should be string or long, not double or float.

2. Step 2: Analyze options for correct types

   val bundle = Bundle() bundle.putString("item_name", "shoes") bundle.putString("price", "59.99") firebaseAnalytics.logEvent("purchase", bundle) uses putString for both item_name and price, which is safe and accepted for Firebase Analytics parameters.

3. Final Answer:

   val bundle = Bundle() bundle.putString("item_name", "shoes") bundle.putString("price", "59.99") firebaseAnalytics.logEvent("purchase", bundle) -> Option C

4. Quick Check:

   Use putString for parameters to avoid type issues = A [OK]

Hint: Use putString for all parameters to ensure compatibility [OK]

Common Mistakes:

• Using putDouble or putFloat which may cause errors
• Putting numbers in wrong parameter keys
• Using putInt for string values