habitica-android/Habitica/res/layout/challenge_add_task_item.xml

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

    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#FFF"
    android:orientation="vertical"
    android:gravity="center">


    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="22dp"
        android:layout_marginBottom="18dp"
        android:layout_marginEnd="24dp"
        android:layout_marginStart="24dp"
        android:textAllCaps="false"
        style="@style/Subheader2"
        android:textColor="?colorAccent"
        android:background="#f9f9f9"
        android:id="@+id/btn_add_task"
        tools:text="Add habit">

    </Button>

</LinearLayout>