Firebase setup for Flutter - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the first step to connect a Flutter app with Firebase?

Create a Firebase project in the Firebase Console and register your Flutter app by adding its package name.

beginner

Which file must be downloaded and added to your Flutter project for Android Firebase setup?

The google-services.json file must be downloaded from Firebase Console and placed in the android/app folder.

beginner

What is the purpose of the firebase_core package in Flutter?

It initializes Firebase in your Flutter app, allowing you to use Firebase services.

intermediate

How do you initialize Firebase in your Flutter app's main function?

Use WidgetsFlutterBinding.ensureInitialized(); then call await Firebase.initializeApp(); before running the app.

intermediate

What additional step is required for iOS Firebase setup after downloading GoogleService-Info.plist?

Add the GoogleService-Info.plist file to the Runner project in Xcode and configure the ios/Podfile to use platform iOS 10 or higher.

Which Firebase package is essential to initialize Firebase in a Flutter app?

A cloud_firestore

B firebase_core

C firebase_auth

D firebase_storage

The firebase_core package is required to initialize Firebase before using any other Firebase services.

Where should the google-services.json file be placed in a Flutter project?

A android/app

B ios/Runner

C lib

D android

The google-services.json file must be placed inside the android/app folder for Android Firebase setup.

What command ensures Flutter widgets are initialized before Firebase initialization?

A WidgetsFlutterBinding.ensureInitialized()

B runApp()

C Firebase.initializeApp()

D main()

WidgetsFlutterBinding.ensureInitialized() makes sure Flutter is ready before calling Firebase.initializeApp().

For iOS, which file must be added to the Xcode project for Firebase?

A google-services.json

B Podfile

C Info.plist

D GoogleService-Info.plist

GoogleService-Info.plist is the configuration file for Firebase on iOS and must be added to the Xcode project.

What minimum iOS platform version is recommended for Firebase in Flutter?

A iOS 9

B iOS 8

C iOS 10

D iOS 12

Firebase requires iOS 10 or higher for proper functionality in Flutter apps.

Describe the steps to set up Firebase for a new Flutter Android app.

Think about what files and code changes are needed for Android.

Explain how to initialize Firebase in a Flutter app and why it is necessary.

Focus on the main function and app startup.

Practice

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

easy

A. Add Firebase dependencies after running the app

B. Write Flutter UI code

C. Create a Firebase project in the Firebase console

D. Run the app without any setup

Solution

1. Step 1: Access Firebase Console

   You must first create a Firebase project in the Firebase console to get started.

2. Step 2: Prepare for Flutter integration

   After creating the project, you can download config files and add dependencies.

3. Final Answer:

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

4. Quick Check:

   First step = Create Firebase project [OK]

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

Common Mistakes:

• Skipping Firebase project creation
• Trying to run app before setup
• Adding dependencies too late

2. Which file must be added to your Flutter Android app after creating a Firebase project?

easy

A. google-services.json

B. GoogleService-Info.plist

C. firebase-config.xml

D. firebase-settings.json

Solution

1. Step 1: Identify Android config file

   For Android apps, Firebase requires the google-services.json file.

2. Step 2: Add file to Android app folder

   This file must be placed in the android/app directory of your Flutter project.

3. Final Answer:

   google-services.json -> Option A

4. Quick Check:

   Android config file = google-services.json [OK]

Hint: Android uses google-services.json config file [OK]

Common Mistakes:

• Using iOS plist file for Android
• Misnaming the config file
• Placing file in wrong folder

3. What will happen if you forget to call Firebase.initializeApp() before runApp() in Flutter?

medium

A. App runs normally without Firebase

B. App crashes on build time

C. Firebase features work partially

D. App throws an error at runtime

Solution

1. Step 1: Understand Firebase initialization

   Firebase must be initialized before the app runs to set up services properly.

2. Step 2: Consequence of missing initialization

   If Firebase.initializeApp() is not called first, the app will throw a runtime error when Firebase is accessed.

3. Final Answer:

   App throws an error at runtime -> Option D

4. Quick Check:

   Missing initializeApp() = runtime error [OK]

Hint: Always initialize Firebase before runApp() [OK]

Common Mistakes:

• Calling initializeApp() after runApp()
• Assuming app runs without initialization
• Ignoring runtime errors

4. You added google-services.json but forgot to add the Firebase plugin in build.gradle. What is the likely result?

medium

A. Firebase services work fine anyway

B. Build fails with plugin not found error

C. App runs but Firebase features are disabled

D. App crashes only on iOS devices

Solution

1. Step 1: Role of Firebase plugin in build.gradle

   The Firebase plugin is required to process the config file and link Firebase SDK during build.

2. Step 2: Effect of missing plugin

   Without the plugin, the build system cannot find Firebase tasks, causing a build failure.

3. Final Answer:

   Build fails with plugin not found error -> Option B

4. Quick Check:

   Missing plugin = build failure [OK]

Hint: Add Firebase plugin in build.gradle to avoid build errors [OK]

Common Mistakes:

• Only adding config file without plugin
• Ignoring build errors
• Assuming plugin is optional

5. You want to support both Android and iOS in your Flutter app with Firebase. Which steps are required?

hard

A. Add google-services.json for Android and GoogleService-Info.plist for iOS, then initialize Firebase in main

B. Add only google-services.json and initialize Firebase in main

C. Add only GoogleService-Info.plist and initialize Firebase in main

D. Initialize Firebase in main without adding any config files

Solution

1. Step 1: Add platform-specific config files

   Android requires google-services.json and iOS requires GoogleService-Info.plist to connect to Firebase.

2. Step 2: Initialize Firebase in main function

   Call Firebase.initializeApp() before runApp() to set up Firebase services.

3. Final Answer:

   Add google-services.json for Android and GoogleService-Info.plist for iOS, then initialize Firebase in main -> Option A

4. Quick Check:

   Both config files + initialize = correct setup [OK]

Hint: Add both config files and initialize Firebase before runApp() [OK]

Common Mistakes:

• Adding only one platform's config file
• Forgetting to initialize Firebase
• Assuming config files auto-load