Firebase project setup in Android Kotlin - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Firebase Project Initialization

What is the first step to connect your Android app to a Firebase project?

A Download the google-services.json file and place it anywhere in your project folder.

B Add Firebase dependencies to your build.gradle file before creating a Firebase project.

C Create a Firebase project in the Firebase console and register your Android app with its package name.

D Write Kotlin code to initialize Firebase in your MainActivity before creating a Firebase project.

💡 Hint

Think about what you need to do before adding code or files.

You must first create a Firebase project in the Firebase console and register your Android app using its package name. This generates the configuration file needed for your app.

❓ ui_behavior

intermediate

Placing google-services.json

Where should you place the google-services.json file in your Android project for Firebase to work correctly?

A In the app/ directory of your Android project.

B In the build/ directory.

C In the src/main/java/ directory.

D In the root directory of your Android project.

💡 Hint

It should be where your app module files are.

The google-services.json file must be placed inside the app/ directory (the module folder) so the Firebase Gradle plugin can find it during build.

📝 Syntax

advanced

Adding Firebase Plugin in build.gradle

Which line correctly applies the Firebase plugin in your app-level build.gradle file?

Android Kotlin

plugins {
    id("com.android.application")
    // Add Firebase plugin here
}

A apply plugin: 'firebase-google-services'

B apply plugin: 'com.google.gms.google-services'

C id("com.google.firebase")

D id("com.google.gms.google-services")

💡 Hint

Use the plugins block syntax with the correct plugin id.

The correct plugin id to apply in the plugins block is "com.google.gms.google-services". The other options are either old syntax or incorrect plugin ids.

❓ lifecycle

advanced

Firebase Initialization Timing

When is the best time to initialize Firebase in your Android app to ensure it works properly?

A In the onCreate() method of your Application class before any UI is created.

B In the onStart() method of your MainActivity after UI is visible.

C In the onResume() method of your MainActivity after user interaction.

D In a background thread after the app has fully loaded.

💡 Hint

Think about when Firebase services should be ready for use.

Initializing Firebase in the Application class's onCreate() ensures Firebase is ready before any activity or UI loads.

🔧 Debug

expert

Debugging Missing Firebase Configuration

Your app crashes with a runtime error saying "Default FirebaseApp is not initialized". Which of the following is the most likely cause?

A You did not add Firebase dependencies in the project-level build.gradle file.

B The google-services.json file is missing or placed in the wrong folder.

C You forgot to add internet permission in AndroidManifest.xml.

D You initialized Firebase twice in your Application class.

💡 Hint

Check if the configuration file is correctly included.

This error usually means the app cannot find the Firebase config file (google-services.json) or it is not placed in the correct location.