How to check if a Firebase App is already initialized on Android

Question

With the following, the first time it's called it works, but then fails on subsequent calls with "FirebaseApp name [DEFAULT] already exists!"

public FirebaseDatabase conn(Context c) {
         FirebaseOptions options = new FirebaseOptions.Builder()
                .setApiKey("key")
                .setDatabaseUrl("url")
                .setApplicationId("ID")
                .build();


        /////I tried Try and Catch with no success//////
        FirebaseApp app = FirebaseApp.initializeApp(c, options);

        /// for this : FirebaseApp app = FirebaseApp.initializeApp(c, options, "some_app");
        //// will fail with "FirebaseApp name some_app already exists!"
        return FirebaseDatabase.getInstance(app);
}

All of the above is an attempt to connect to a second Firebase App.

score 225 · Accepted Answer · edited Feb 12 '20 at 15:49

225

On firebase web, you check if already initialized with:

if (firebase.apps.length === 0) {
    firebase.initializeApp({});
}

edited Feb 12 '20 at 15:49

Franck Jeannin

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answered Dec 06 '16 at 21:18

Daniel Laurindo

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3

Cool but in android this impossible – Vlad Jan 19 '18 at 13:08
I had been using the `App` returned from `initializeApp()` but with the above approach this is no longer possible, so I'm using now `firebase.app('[DEFAULT]')`, but I'm not sure if that's recommended. – eoinmullan Jul 09 '20 at 21:21
1

@eoinmullan this worked for me https://githubmemory.com/repo/firebase/firebase-js-sdk/issues/5037 – Pumuckelo Aug 03 '21 at 06:33
and in case if you want to get instance in else you can get by `firebase.app();` – cjmling Sep 27 '21 at 07:39
Can you update it to web 9? – Ayush Kumar Nov 16 '21 at 17:47

score 55 · Answer 2 · answered Apr 18 '21 at 00:04

55

In v9, Firebase has been modularized for better tree shaking. So we can no longer import entire app and check the apps property AFAIK. The below approach can be used instead.

import { initializeApp, getApps, getApp } from "firebase/app";
getApps().length === 0 ? initializeApp(firebaseConfig) : getApp();

https://firebase.google.com/docs/reference/js/v9/app.md#getapps for documentation

answered Apr 18 '21 at 00:04

Nitin

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I tried this but I get this error - https://stackoverflow.com/questions/72028182/how-to-initialize-firebase-in-firebase-version-9-firebase-v9/72029160#72029160 – user3399180 Apr 28 '22 at 05:00

score 21 · Answer 3 · answered Jul 03 '21 at 00:26

21

Firebase Version 9

import { initializeApp, getApp } from "firebase/app";

const createFirebaseApp = (config = {}) => {
  try {
    return getApp();
  } catch () {
    return initializeApp(config);
  }
};

const firebaseApp = createFirebaseApp({/* your config */})

answered Jul 03 '21 at 00:26

Max Ma

1,060
9
15

Thank you. One of the few explanations that make sense for being able to export the firebaseApp variable. – Levi Wilkerson Feb 22 '22 at 14:00
How to do it with `firebase-admin` ? Any ideas? – cbdeveloper Sep 12 '22 at 07:29

score 17 · Answer 4 · answered Jun 05 '18 at 11:37

For those wondering how to do the same as the accepted answer, in Android:

if (FirebaseApp.getApps(context).isEmpty()) {
    FirebaseApp.initializeApp(context);
}

and in an instrumented test environment, use this context:

InstrumentationRegistry.getContext()

score 7 · Answer 5 · answered Dec 20 '17 at 17:20

You can try to get the Firebase app instance, in it's code firebase checks if it's initialized, if not it throws an IllegalStateException.

    try{
        FirebaseApp.getInstance();
    }
    catch (IllegalStateException e)
    {
        //Firebase not initialized automatically, do it manually
        FirebaseApp.initializeApp(this);
    }

score 6 · Answer 6 · answered Jun 12 '16 at 22:26

I think what you want to do is check the list of running apps before initializing your app. Each of the SDKs have a method for getting this array, in android it's getApps:

https://firebase.google.com/docs/reference/android/com/google/firebase/FirebaseApp.html

Then you can check to see if your app is already initialized.

In my case I just ended up checking the length of the array (I'm using the javascript / web sdk so I'm sure it's a little different for Android) and initializing a new app if it is 0.

score 3 · Answer 7 · answered May 16 '21 at 20:28

3

In firebase admin SDK for java, initialize the app if and only if there is no app.

if (FirebaseApp.getApps().isEmpty()) {
    FirebaseApp.initializeApp();
}

answered May 16 '21 at 20:28

Ratul Sharker

7,484
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score 2 · Answer 8 · answered Dec 19 '17 at 05:02

2

I faced the similar issue. I solved the following problem by deleting the already initialized app.

    // Access your firebase app
    let app = firebase.app();
    // Delete your app.
    app.delete(app);

Solution works for web.

answered Dec 19 '17 at 05:02

Manoj Pathak

59
3

doesn't work anymore - https://github.com/zeit/next.js/issues/1999#issuecomment-302244429 – Anand Rockzz Jul 01 '19 at 01:42

score 1 · Answer 9 · answered Feb 02 '20 at 06:32

Not sure in android, but how about using a singleton method. In JS you can do this. Hope this helps someone

// Config file
import * as firebase from "firebase";

const config = {...};

export default !firebase.apps.length ? firebase.initializeApp(config) : firebase.app();

// Other file
import firebase from '../firebase';

score 1 · Answer 10 · answered Nov 05 '20 at 12:05

1

import * as firebase from "firebase/app";
firebase.apps.map(e => e.name); // Give you an array of initialized apps

answered Nov 05 '20 at 12:05

Jürgen Brandstetter

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score 1 · Answer 11 · answered Jul 27 '21 at 05:14

1

For those who are using dotNet FirebaseAdmin SDK

if (FirebaseApp.GetInstance("[DEFAULT]") == null)
{
    var createdApp = FirebaseApp.Create(new AppOptions()
    {
        Credential = GoogleCredential.FromFile("private-key.json")
    });
}

answered Jul 27 '21 at 05:14

Zeeshan Ahmad Khalil

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1
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score 0 · Answer 12 · answered Oct 11 '17 at 08:13

I faced the similar issue, I resolved it as following:

Create a var for the application and initialize it with null
Take reference of the application while initialization
Check before initializing it again

//global variable
var firebaseResumeDownloadAdd = null;

//inside function check before initializing
if(firebaseResumeDownloadAdd==null){
   firebaseResumeDownloadAdd =
   firebase.initializeApp(functions.config().firebase);
}

score 0 · Answer 13 · edited Mar 28 '21 at 09:44

0

in Android, depending on Daniel Laurindo's answer:

if (FirebaseApp.getApps(context).size != 0) {

}

edited Mar 28 '21 at 09:44

Harshad Pansuriya

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answered Mar 28 '21 at 09:39

Mina Farid

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score 0 · Answer 14 · answered Jun 14 '21 at 13:47

0

A cleaner solution for ES6+ is


if (!firebase.apps.length) {
 ...
}

answered Jun 14 '21 at 13:47

mr3mo

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score 0 · Answer 15 · answered Jul 06 '21 at 08:59

0

Simple use Java 8 Stream and Optional featured.

Code below as

FirebaseApp.getApps()
.stream()
.filter(firebaseApp -> 
    firebaseApp.getName().equals("APP_NAME"))
   .findFirst()
   .orElseGet(() -> FirebaseApp.initializeApp(firebaseOptions, "APP_NAME"));

answered Jul 06 '21 at 08:59

Yasir Shabbir Choudhary

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score 0 · Answer 16 · answered Apr 07 '22 at 08:31

Th Use Platform check to initialize according to environment

On firebase web, you check if already initialized with

use the below snippet while launching MYAPP()

import 'dart:io';

void main() async {

WidgetsFlutterBinding.ensureInitialized();

if (Platform.isAndroid || Platform.isIOS) {

await Firebase.initializeApp();

} else {

if (Firebase.apps.isEmpty) {

  await Firebase.initializeApp(

      // connect for web to firebase
      options:firebaseOptions

}

} runApp(const MyApp());

}

score 0 · Answer 17 · answered Nov 22 '22 at 09:48

0

const app = !getApps().length ? initializeApp(firebaseConfig) : getApp();

answered Nov 22 '22 at 09:48

RaySun

139
1
5

Just a coding style thing, but I don't think it's good to treat numbers as Booleans like that. – General Grievance Nov 22 '22 at 13:51

score 0 · Answer 18 · answered Jan 13 '23 at 14:36

For web, you could use:

import { getApp, initializeApp } from "firebase/app"

const firebaseConfig = {/* YOUR CONFIG */}

function createFirebaseApp(config) {
    try {
        return getApp()
    } catch {
        return initializeApp(config)
    }
}

const firebaseApp = createFirebaseApp(firebaseConfig)

Explorer · Answer 19 · 2023-02-10T07:03:05.913

As of now, I Do not have access to comments or likes. But I think this point is important to make.

Many good answers here, but it is also essential to talk about the best answers and performance.

Ideally, you want to minimize code that goes into your production and also want to make sure that there are no unnecessary pieces out there. Thus, a tree-shaking solution is best.

I do following

import { initializeApp, getApps, cert } from "firebase-admin/app";

const secret = JSON.parse(process.env.FIREBASE_SECRET || "{}");

if (!getApps().length) initializeApp({ credential: cert(secret) });

score -1 · Answer 20 · answered Mar 14 '20 at 01:07

If you are using Nativescript to build an hybrid mobile app for Android | iOS you can use this script:

import * as firebase from 'nativescript-plugin-firebase';

_initFirebase(): Promise<any> {
    if (!(firebase as any).initialized) {
      return firebase.init({}).then(
        () => {
          console.info('firebase started...');
        },
        (error) => console.error(error)
      );
    }
  }

How to check if a Firebase App is already initialized on Android

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