how to show notification on the icon in ionic code example
Example: ionic cordova icon notification
// Please test if this code added to config.xml <platform name="android"> tag will add the icon as default notification icon.
// Place the notification icon under "resources/android/notification/"
<resource-file src="resources/android/notification/notification_icon.png" target="app/src/main/res/drawable/notification_icon.png" />
<config-file parent="/manifest/application/" target="app/src/main/AndroidManifest.xml">
<meta-data android:name="com.google.firebase.messaging.default_notification_icon" android:resource="@drawable/notification_icon" />
</config-file>