nextcloud-talk-android/app/src/main/res/layout/item_system_message.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Nextcloud Talk application
  ~
  ~ @author Mario Danic
  ~ Copyright (C) 2017-2018 Mario Danic <mario@lovelyhq.com>
  ~
  ~ This program is free software: you can redistribute it and/or modify
  ~ it under the terms of the GNU General Public License as published by
  ~ the Free Software Foundation, either version 3 of the License, or
  ~ at your option) any later version.
  ~
  ~ This program is distributed in the hope that it will be useful,
  ~ but WITHOUT ANY WARRANTY; without even the implied warranty of
  ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  ~ GNU General Public License for more details.
  ~
  ~ You should have received a copy of the GNU General Public License
  ~ along with this program.  If not, see <http://www.gnu.org/licenses/>.
  -->

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginBottom="8dp"
                android:layout_marginEnd="16dp"
                android:layout_marginStart="16dp"
                android:layout_marginTop="8dp">

    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@id/bubble"
        android:layout_centerHorizontal="true">

        <TextView
            android:id="@+id/messageText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:gravity="center_horizontal"
            android:textAlignment="center"
            android:textColor="@color/colorPrimary"
            android:textSize="12sp"/>

    </RelativeLayout>
</RelativeLayout>