mihon/app/src/main/res/layout/navigation_view_spinner.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="?attr/listPreferredItemHeightSmall"
    android:background="?attr/selectableItemBackground"
    android:focusable="true"
    android:paddingStart="?attr/listPreferredItemPaddingStart"
    android:paddingEnd="?attr/listPreferredItemPaddingEnd">

    <TextView
        android:id="@+id/nav_view_item_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <Spinner
        android:id="@+id/nav_view_item"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:gravity="center_vertical|start"
        android:maxLines="1"
        android:textAppearance="@style/TextAppearance.AppCompat.Body2" />

</LinearLayout>