Firebase project setup in Android Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the first step to start using Firebase in your Android app?

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

beginner

What file do you download from Firebase Console to connect your Android app to Firebase?

You download the google-services.json file and add it to your app's app/ folder.

beginner

Which Gradle plugin must be added to your Android app to enable Firebase services?

Add the com.google.gms.google-services plugin in your app-level build.gradle file.

beginner

Why do you need to add Firebase SDK dependencies in your app's build.gradle file?

To include Firebase features like Authentication, Firestore, or Analytics in your app, you add their SDK libraries as dependencies.

beginner

What is the purpose of syncing your project with Gradle after adding Firebase dependencies?

Syncing downloads the required libraries and prepares your project to use Firebase features without errors.

Where do you register your Android app to create a Firebase project?

A Firebase Console

B Google Play Store

C Android Studio

D GitHub

You register your app in the Firebase Console to link it with Firebase services.

What is the name of the configuration file you add to your Android app for Firebase?

A firebase-config.xml

B google-services.json

C firebase.json

D google-config.xml

The google-services.json file contains Firebase project info for your Android app.

Which Gradle file do you add Firebase SDK dependencies to?

A Project-level build.gradle

B Settings.gradle

C App-level build.gradle

D Manifest.xml

Firebase SDK dependencies go in the app-level build.gradle file.

What plugin must be applied in your app-level build.gradle to enable Firebase?

A com.google.gms.google-services

B firebase-plugin

C kotlin-android

D com.android.application

The com.google.gms.google-services plugin connects your app with Firebase.

Why is syncing your project with Gradle important after adding Firebase?

A To update Android Studio

B To clean the project

C To run the app automatically

D To download Firebase libraries and avoid build errors

Syncing downloads required Firebase libraries so your app builds correctly.

Describe the steps to set up Firebase in a new Android app from scratch.

Think about what you do in Firebase Console and what files and settings you add in Android Studio.

Explain why the google-services.json file is important in Firebase setup for Android.

Consider what information your app needs to communicate with Firebase.

Practice

1. What is the first step to connect your Android app to Firebase?

easy

A. Add dependencies in the app's build.gradle file

B. Create a Firebase project in the Firebase console

C. Download the google-services.json file

D. Run the app on an emulator

Solution

1. Step 1: Access Firebase Console

   You need to start by creating a Firebase project in the Firebase console to link your app with Firebase services.

2. Step 2: Prepare for app integration

   Only after creating the project can you download configuration files and add dependencies.

3. Final Answer:

   Create a Firebase project in the Firebase console -> Option B

4. Quick Check:

   First step = Create Firebase project [OK]

Hint: Start by creating the Firebase project online [OK]

Common Mistakes:

• Trying to add dependencies before creating the project
• Downloading google-services.json before project setup
• Running app without Firebase configuration

2. Which line correctly adds the Firebase plugin in the project-level build.gradle file?

easy

A. classpath 'com.google.gms:google-services:4.3.15'

B. implementation 'com.google.firebase:firebase-analytics:21.3.0'

C. apply plugin: 'com.android.application'

D. compile 'com.google.firebase:firebase-core:16.0.9'

Solution

1. Step 1: Identify plugin declaration

   The Firebase plugin is added in the project-level build.gradle under dependencies using the classpath keyword.

2. Step 2: Match correct syntax

   classpath 'com.google.gms:google-services:4.3.15' uses classpath with the correct Firebase plugin version format.

3. Final Answer:

   classpath 'com.google.gms:google-services:4.3.15' -> Option A

4. Quick Check:

   Firebase plugin uses classpath in project build.gradle [OK]

Hint: Firebase plugin uses classpath, not implementation [OK]

Common Mistakes:

• Using implementation instead of classpath for plugin
• Adding plugin in app-level build.gradle instead of project-level
• Using outdated or incorrect plugin versions

3. Given this snippet in the app-level build.gradle file:

plugins {
    id 'com.android.application'
    id 'com.google.gms.google-services'
}
dependencies {
    implementation 'com.google.firebase:firebase-analytics:21.3.0'
}

What happens when you sync the project?

medium

A. The project syncs but Firebase Analytics is not included

B. Build fails because the google-services plugin is not applied correctly

C. The app runs without Firebase Analytics features

D. The Firebase Analytics library is added and the google-services plugin is applied successfully

Solution

1. Step 1: Check plugin application

   The plugin 'com.google.gms.google-services' is applied correctly in the plugins block, which is the modern way.

2. Step 2: Verify dependency inclusion

   The Firebase Analytics library is included in dependencies, so it will be added on sync.

3. Final Answer:

   The Firebase Analytics library is added and the google-services plugin is applied successfully -> Option D

4. Quick Check:

   Correct plugin + dependency = successful sync [OK]

Hint: Check plugins block for google-services plugin [OK]

Common Mistakes:

• Applying plugin in wrong Gradle file
• Forgetting to add Firebase dependencies
• Using old apply plugin syntax with plugins block

4. You added the google-services.json file but your app crashes on startup with a missing resource error. What is the likely cause?

medium

A. You forgot to add Firebase dependencies in build.gradle

B. You did not create a Firebase project in the console

C. The google-services.json file is placed in the wrong folder

D. You did not enable internet permission in AndroidManifest.xml

Solution

1. Step 1: Understand google-services.json placement

   This file must be placed in the app module folder (usually app/) to be recognized during build.

2. Step 2: Identify error cause

   If placed elsewhere, the build system cannot find required resources, causing crashes.

3. Final Answer:

   The google-services.json file is placed in the wrong folder -> Option C

4. Quick Check:

   Correct file location prevents resource errors [OK]

Hint: Place google-services.json inside the app folder [OK]

Common Mistakes:

• Putting google-services.json in the project root
• Not syncing project after adding the file
• Ignoring build errors related to Firebase

5. You want to add Firebase Authentication to your Android app. After creating the Firebase project and adding google-services.json, what is the correct sequence to set up your app?

hard

A. Add Firebase Auth dependency, apply google-services plugin, sync project, then initialize FirebaseAuth in code

B. Initialize FirebaseAuth in code, add dependency, apply plugin, then sync project

C. Apply google-services plugin, initialize FirebaseAuth in code, add dependency, then sync project

D. Sync project, add dependency, apply plugin, then initialize FirebaseAuth in code

Solution

1. Step 1: Add Firebase Auth dependency

   First, add the Firebase Authentication library in the app-level build.gradle dependencies.

2. Step 2: Apply google-services plugin and sync

   Apply the google-services plugin in the app-level build.gradle and sync the project to integrate Firebase services.

3. Step 3: Initialize FirebaseAuth in code

   Finally, initialize FirebaseAuth in your Kotlin code to use authentication features.

4. Final Answer:

   Add Firebase Auth dependency, apply google-services plugin, sync project, then initialize FirebaseAuth in code -> Option A

5. Quick Check:

   Dependency -> plugin -> sync -> code init [OK]

Hint: Add dependency and plugin before coding FirebaseAuth [OK]

Common Mistakes:

• Initializing FirebaseAuth before adding dependencies
• Forgetting to sync project after changes
• Applying plugin after coding initialization