Firebase Analytics in Android Kotlin - Mini App: Build & Ship

Build: AnalyticsDemoScreen

This screen logs a custom event to Firebase Analytics when a button is clicked and shows a confirmation message.

Target UI

-------------------------
| Firebase Analytics Demo |
|-----------------------|
|                       |
|   [ Log Event Button ] |
|                       |
-------------------------

Add a Button labeled 'Log Event Button' in the center of the screen.

When the button is clicked, log a custom event named 'button_click' with a parameter 'button_name' set to 'Log Event Button' using Firebase Analytics.

Show a Toast message confirming the event was logged.

Starter Code

Android Kotlin

package com.example.analyticsdemo

import android.os.Bundle
import android.widget.Button
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.google.firebase.analytics.FirebaseAnalytics

class AnalyticsDemoScreen : AppCompatActivity() {
    private lateinit var firebaseAnalytics: FirebaseAnalytics

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_analytics_demo_screen)

        firebaseAnalytics = FirebaseAnalytics.getInstance(this)

        val logEventButton: Button = findViewById(R.id.logEventButton)

        // TODO: Add click listener to log event and show Toast
    }
}

Task 1

Task 2

Task 3

Task 4

Solution

Android Kotlin

package com.example.analyticsdemo

import android.os.Bundle
import android.widget.Button
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.google.firebase.analytics.FirebaseAnalytics

class AnalyticsDemoScreen : AppCompatActivity() {
    private lateinit var firebaseAnalytics: FirebaseAnalytics

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_analytics_demo_screen)

        firebaseAnalytics = FirebaseAnalytics.getInstance(this)

        val logEventButton: Button = findViewById(R.id.logEventButton)

        logEventButton.setOnClickListener {
            val params = Bundle().apply {
                putString("button_name", "Log Event Button")
            }
            firebaseAnalytics.logEvent("button_click", params)
            Toast.makeText(this, "Event logged!", Toast.LENGTH_SHORT).show()
        }
    }
}

We first get the FirebaseAnalytics instance for the current context. Then we find the button by its ID. We add a click listener to the button. When clicked, we create a Bundle to hold event parameters, here setting 'button_name' to identify which button was clicked. We call logEvent on the FirebaseAnalytics instance with the event name 'button_click' and the parameters. Finally, we show a Toast message to confirm the event was logged. This helps track user interactions in the app.

Final Result

Completed Screen

-------------------------
| Firebase Analytics Demo |
|-----------------------|
|                       |
|   [ Log Event Button ] |
|                       |
-------------------------

User taps the 'Log Event Button'.

App logs 'button_click' event with parameter 'button_name' = 'Log Event Button' to Firebase Analytics.

A short Toast message 'Event logged!' appears at the bottom.

Stretch Goal

Add a second button labeled 'Log Screen View' that logs a screen_view event with the screen name 'AnalyticsDemoScreen'.

💡 Hint

Use firebaseAnalytics.logEvent(FirebaseAnalytics.Event.SCREEN_VIEW, Bundle().apply { putString(FirebaseAnalytics.Param.SCREEN_NAME, "AnalyticsDemoScreen") }) inside the button's click listener.

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