session-android/res/layout/reminder_header.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:tools="http://schemas.android.com/tools"
              android:orientation="vertical"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content">
    <LinearLayout android:id="@+id/container"
                  android:orientation="horizontal"
                  android:layout_width="match_parent"
                  android:layout_height="wrap_content"
                  android:visibility="gone"
                  tools:visibility="visible"
                  android:padding="2dp"
                  android:gravity="center_vertical"
                  android:background="?reminder_header_background">

        <LinearLayout android:id="@+id/reminder"
                      android:layout_width="0dp"
                      android:layout_height="wrap_content"
                      android:layout_weight="1"
                      android:layout_margin="10dp"
                      android:orientation="vertical">

            <TextView android:id="@+id/reminder_title"
                      android:layout_width="wrap_content"
                      android:layout_height="wrap_content"
                      android:layout_marginBottom="5dp"
                      tools:text="Invite to Signal"
                      android:textColor="@color/white"
                      android:textSize="18sp"/>

            <TextView android:id="@+id/reminder_text"
                      android:layout_width="wrap_content"
                      android:layout_height="wrap_content"
                      tools:text="Take your conversation with Jules Bonnot to the next level."
                      android:fontFamily="sans-serif-light"
                      android:textColor="@color/white"
                      android:textSize="16sp"/>

        </LinearLayout>

        <LinearLayout android:layout_width="wrap_content"
                      android:layout_height="match_parent"
                      android:gravity="right"
                      android:layout_marginLeft="15dp"
                      android:orientation="vertical">

            <LinearLayout android:layout_width="wrap_content"
                          android:layout_height="0dp"
                          android:layout_weight="1"
                          android:gravity="top">

                <ImageButton android:id="@+id/cancel"
                             android:layout_width="40dp"
                             android:layout_height="40dp"
                             android:padding="10dp"
                             android:background="@drawable/touch_highlight_background"
                             android:src="@drawable/ic_close_white_24dp"/>
            </LinearLayout>
          </LinearLayout>

    </LinearLayout>
</LinearLayout>