Setup Firebase in Flutter (Visual Guide)

Last updated: 2020-07-25

This guide was tested on Flutter 1.17.5.

Flutter 1.17.5 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 8af6b2f038 (4 weeks ago) • 2020-06-30 12:53:55 -0700
Engine • revision ee76268252
Tools • Dart 2.8.4

Firebase Account Setup

Create Firebase Project

Set Project's Name

Configure Firebase Analytics

Select Your Target: iOS or Android

Register App

Download Firebase Config File

Add Firebase SDK

In android/build.gradle (root-level / project-level)

buildscript {

    repositories {
      // Check that you have the following line (if not, add it):
      google()  // Google's Maven repository
    }

    // ...

    dependencies {
      // ...

      // Add the following line:
      classpath 'com.google.gms:google-services:4.3.3'  // Google Services plugin
    }
}

allprojects {
    // ...

    repositories {
      // Check that you have following line (if not, add it):
      google()  // Google's Maven repository
      // ...
    }
}

In android/app/build.gradle (app-level)

// Add the following line:
apply plugin: 'com.google.gms.google-services'  // Google Services plugin

android {
  // ...
}

// ...

Finalize Firebase Setup

Setup Firestore Database

Create Database

Set Database Location

Add Entries to Database

Configure Your Flutter App

Add FlutterFire plugin to pubspec.yaml

dependencies:
  flutter:
    sdk: flutter
  firebase_core:
  cloud_firestore:

Run flutter packages get.

Troubleshootings

Error Plugin project :firebase_core_web not found

Add the following content to android/app/settings.gradle:

def flutterProjectRoot = rootProject.projectDir.parentFile.toPath()

def plugins = new Properties()
def pluginsFile = new File(flutterProjectRoot.toFile(), '.flutter-plugins')
if (pluginsFile.exists()) {
    pluginsFile.withReader('UTF-8') { reader -> plugins.load(reader) }
}

plugins.each { name, path ->
    def pluginDirectory = flutterProjectRoot.resolve(path).resolve('android').toFile()
    include ":$name"
    project(":$name").projectDir = pluginDirectory
}

(Reference)

Error D8: Cannot fit requested classes in a single dex file

Enable multidex support by adjusting android/app/bundle.gradle:

android {

    defaultConfig {
        ...

        // Enabling multidex support.
        multiDexEnabled true
    }
    ...
}