We are going to use MIT app inventor 2 to create our Android app. Its very simple to use and easy to integrate win Google firebase.

You can do it in two ways:-

Way one:-

Create a new app, and then make the layout (as shown in screenshot 1).

After that, create code logic (as shown in screenshot 2).

Way two:-

Alternatively, you can download the project (.aia file) attached below

Then go to MIT app inventor >> projects >> import project (as shown in screenshot 3). Select the file from your computer and upload it. After that open project and navigate to screen2 (as shown in screenshot 4).

Once layout and code logic is ready, go to layout window, click on firebaseDB1 (located at bottom of the workspace), enter database URL and secret key. Also keep ProjectBucket field empty (as shown in screenshot 5).

After that, click on the build button and save app file (.apk file) to your computer. Later transfer that file to your Android device.