Layout login activity - adding progress view

activity_login.xml

<!--

login_image
login_username
login_password
login_button

-->

<LinearLayout
    android:id="@+id/progress_view"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:gravity="center_horizontal"
    android:orientation="vertical"
    android:visibility="gone"
    tools:visibility="visible">

  <ProgressBar
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      style="@android:style/Widget.DeviceDefault.ProgressBar" />

  <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="@string/loading" />
</LinearLayout>