SchildiChat-android/vector/src/main/res/drawable/red_dot.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">

    <size
        android:width="8dp"
        android:height="8dp" />

    <solid android:color="?colorError" />

</shape>