Grey icon on notifications

[Carlos Mota]

On recent versions of Android, the system ignores non-alpha channels in notification icons. In other words, if we have an icon which is composed by a background color and several railroads the system will merge everything into a solid colour; on my case the default one is grey.

This can easily be fixed by creating a notification icon without the white background and setting it on the manifest file via meta-data:

<meta-data
            android:name="com.google.firebase.messaging.default_notification_icon"
            android:resource="@drawable/ic_notification_icon" />