How To Send OneSignal Firebase Notification in Flutter

Getting Started With the OneSignal

Step 1: App Registration with OneSignal.

• Register an account at OneSignal.
• Click on Add a new app. Select the android and Fill in the name of the app and click configure your platform.

• Click On Configure your Platform.

Step 2: Add the firebase server Key and sender id.

• To find the firebase server key and the sender id go to your firebase console.
• open the project->project setting and select the Cloud Messaging. Then you find the server key and sender Id.

• Now fill in the server key and the sender id and click on the Save & Continue.

• Then Select the platform as Flutter and continue. then Click on Done.
• Now in the OneSignal website navigate to the Settings->Keys & IDs to find your App Id and Rest API Key

Step 3: Integrate the one signal to your Flutter App.

• Add the one signal Plugin to the pubspec.yaml file and run Pub get.
• Navigate to android->app->build. gradle and add the following lines of code.

buildscript {
    repositories {
        // ...
        maven { url 'https://plugins.gradle.org/m2/' } // Gradle Plugin Portal
    }
    dependencies {
        // ...
        // OneSignal-Gradle-Plugin
        classpath 'gradle.plugin.com.onesignal:onesignal-gradle-plugin:[0.12.6, 0.99.99]'
    }
}

apply plugin: 'com.onesignal.androidsdk.onesignal-gradle-plugin'

• Initialize the one signal by adding the following line of code in the init state of the main. dart file of your project.

@override
  void initState() {
    super.initState();
    configOneSignel();
  }

  void configOneSignel()
  {
    OneSignal.shared.init('7d108336-42a4-4e9f-9a23-6105dd125a74');
  }

• Build your App Now, This would register a user on the one signal.
• After building the flutter application check the dashBoard on the OneSignal website to view the subscribed users.

Step 4: Go to the Message in the OneSignal page and make a notification.

• Click the Send Message button.

Output:

Reference:
https://sanjay144.medium.com/how-to-send-notification-from-device-to-device-in-flutter-7a47c911d66