tt-rss-android/org.fox.ttrss/src/main/res/layout/activity_login.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:fitsSystemWindows="true"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <include layout="@layout/toolbar" android:id="@+id/toolbar" />

        <TextView
            android:background="?android:colorBackground"
            android:id="@+id/loading_message"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center"
            android:text="@string/loading_message" />

</FrameLayout>