k-9/res/layout/message_view_header.xml

<?xml version="1.0" encoding="utf-8"?>
<com.fsck.k9.view.MessageHeader
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/header_container"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

    <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

        <TextView
                android:id="@+id/subject"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:maxLines="3"
                android:ellipsize="end"
                android:textStyle="bold"
                android:textColor="?android:attr/textColorPrimary"
                android:textAppearance="?android:attr/textAppearanceMedium"
                android:text="@string/general_no_subject"
                android:padding="8dp" />

        <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal">

            <!-- Color chip -->
            <View
                    android:id="@+id/chip"
                    android:layout_width="6dip"
                    android:layout_height="match_parent"
                    android:layout_marginRight="6dip"/>

            <RelativeLayout
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:orientation="vertical">

                <QuickContactBadge
                        android:id="@+id/contact_badge"
                        android:layout_width="40dp"
                        android:layout_height="40dp"
                        android:layout_marginTop="8dp"
                        android:layout_marginLeft="8dp" />

                <!-- State icons -->
                <LinearLayout
                        android:id="@+id/icon_container"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_marginTop="10dip"
                        android:layout_marginBottom="2dip"
                        android:layout_below="@+id/contact_badge"
                        android:layout_centerHorizontal="true"
                        android:orientation="vertical">

                    <View
                            android:id="@+id/answered"
                            android:layout_width="32sp"
                            android:layout_height="32sp"
                            android:paddingRight="2dip"
                            android:background="@drawable/ic_email_answered_small"/>

                    <View
                            android:id="@+id/forwarded"
                            android:layout_width="22sp"
                            android:layout_height="22sp"
                            android:paddingRight="4dip"
                            android:background="@drawable/ic_email_forwarded_small"/>

                </LinearLayout>

            </RelativeLayout>

            <RelativeLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:padding="6dip"
                    android:layout_marginLeft="4dp">

                <!-- From -->
                <TextView
                        android:id="@+id/from"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_alignParentTop="true"
                        android:layout_alignParentLeft="true"
                        android:layout_toLeftOf="@+id/flagged"
                        android:paddingTop="0dp"
                        android:paddingRight="6dip"
                        android:singleLine="true"
                        android:ellipsize="end"
                        android:textColor="?android:attr/textColorPrimary"
                        android:textAppearance="?android:attr/textAppearanceMedium"
                        android:textStyle="bold"
                        android:text="@string/general_no_sender" />

                <!-- To -->
                <TextView
                        android:id="@+id/to_label"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_alignLeft="@+id/from"
                        android:layout_alignBaseline="@+id/to"
                        android:paddingTop="2dp"
                        android:paddingRight="4dp"
                        android:text="@string/message_to_label"
                        android:textColor="?android:attr/textColorPrimary"
                        android:textAppearance="@android:style/TextAppearance.Medium"
                        android:textStyle="bold" />

                <TextView
                        android:id="@+id/to"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_toRightOf="@+id/to_label"
                        android:layout_below="@+id/from"
                        android:layout_toLeftOf="@+id/flagged"
                        android:maxLines="2"
                        android:ellipsize="end"
                        android:paddingTop="2dp"
                        android:textColor="?android:attr/textColorSecondary"
                        android:textAppearance="@android:style/TextAppearance.Medium" />

                <!-- CC -->
                <TextView
                        android:id="@+id/cc_label"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_below="@+id/to_label"
                        android:layout_alignLeft="@+id/to_label"
                        android:layout_alignBaseline="@+id/cc"
                        android:paddingTop="2dp"
                        android:paddingRight="4dp"
                        android:text="@string/message_view_cc_label"
                        android:textColor="?android:attr/textColorPrimary"
                        android:textStyle="bold"
                        android:textAppearance="@android:style/TextAppearance.Medium" /> -->

                <TextView
                        android:id="@+id/cc"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_toRightOf="@+id/cc_label"
                        android:layout_below="@+id/to"
                        android:layout_toLeftOf="@+id/flagged"
                        android:maxLines="2"
                        android:ellipsize="end"
                        android:paddingTop="2dp"
                        android:textColor="?android:attr/textColorSecondary"
                        android:textAppearance="@android:style/TextAppearance.Medium" />

                <!-- Date -->
                <TextView
                        android:id="@+id/date"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_below="@id/cc"
                        android:layout_alignParentRight="true"
                        android:paddingTop="8dp"
                        android:singleLine="true"
                        android:ellipsize="none"
                        android:textAppearance="?android:attr/textAppearanceSmall"
                        android:textColor="?android:attr/textColorSecondary" />

                <CheckBox
                        android:id="@+id/flagged"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_alignParentRight="true"
                        android:layout_alignTop="@id/from"
                        android:focusable="false"
                        style="?android:attr/starStyle"
                        android:checked="false" />

            </RelativeLayout>

        </LinearLayout>

        <TextView
                android:id="@+id/additional_headers_view"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:layout_margin="10dp"
                android:layout_marginRight="6dip"
                android:singleLine="false"
                android:ellipsize="none"
                android:textColor="?android:attr/textColorSecondary"
                android:textAppearance="?android:attr/textAppearanceSmall"
                android:textIsSelectable="true" />

        <View
                android:layout_height="1dip"
                android:layout_width="match_parent"
                android:layout_alignParentLeft="true"
                android:layout_below="@id/additional_headers_view"
                android:background="@drawable/divider_horizontal_email"/>

        <!-- Button area -->
        <LinearLayout
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:gravity="right"
                android:paddingLeft="6dip"
                android:paddingRight="6dip"
                android:paddingTop="4dip"
                android:baselineAligned="false">

            <Button
                    android:id="@+id/show_pictures"
                    android:layout_width="wrap_content"
                    android:visibility="gone"
                    android:layout_marginLeft="6dip"
                    android:layout_marginBottom="4dip"
                    android:layout_height="wrap_content"
                    android:text="@string/message_view_show_pictures_action"
                    style="?android:attr/buttonStyleSmall"/>

            <Button
                    android:id="@+id/show_attachments"
                    android:visibility="gone"
                    android:layout_marginLeft="6dip"
                    android:layout_marginBottom="4dip"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/message_view_show_attachments_action"
                    style="?android:attr/buttonStyleSmall"/>

            <Button
                    android:id="@+id/show_message"
                    android:visibility="gone"
                    android:layout_marginLeft="6dip"
                    android:layout_marginBottom="4dip"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/message_view_show_message_action"
                    style="?android:attr/buttonStyleSmall"/>

        </LinearLayout>

        <include layout="@layout/message_view_crypto_layout"/>

    </LinearLayout>

</com.fsck.k9.view.MessageHeader>