dialog_new_achievement.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:padding="12dp"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
        <Spinner
                android:layout_width="match_parent"
                android:id="@+id/achievement_name"
                android:layout_height="wrap_content"/>
</LinearLayout>