android/app/src/main/res/drawable/login_rectangle.xml

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

    <solid
        android:color="@android:color/white"/>

    <size
        android:width="339dp"
        android:height="150dp"/>
</shape>