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="fill_parent"
    android:layout_height="wrap_content">

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

        <!-- Message header area -->
        <TableLayout
            android:id="@+id/top_container"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:stretchColumns="1"
            android:shrinkColumns="1"
            android:background="@color/message_view_header_background">

            <TableRow>

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

                <LinearLayout
                    android:paddingTop="2dip"
                    android:layout_column="1"
                    android:layout_height="wrap_content"
                    android:orientation="vertical">

                    <!-- Subject -->
                    <TextView
                        android:id="@+id/subject"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:maxLines="3"
                        android:ellipsize="end"
                        android:textSize="10sp"
                        android:textStyle="bold"
                        android:textColor="?android:attr/textColorSecondary"
                        android:textAppearance="?android:attr/textAppearanceSmall"/>

                    <!-- From -->
                    <LinearLayout
                        android:id="@+id/from_container"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content">

                        <TextView
                            android:id="@+id/from"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:paddingRight="6dip"
                            android:singleLine="true"
                            android:ellipsize="end"
                            android:textColor="?android:attr/textColorPrimary"
                            android:textAppearance="?android:attr/textAppearanceSmall"/>

                    </LinearLayout>

                    <!-- To -->
                    <LinearLayout
                        android:id="@+id/to_container"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:baselineAligned="true">

                        <TextView
                            android:id="@+id/to_label"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:paddingRight="4dip"
                            android:text="@string/message_to_label"
                            android:textSize="10sp"
                            android:textStyle="bold"
                            android:textColor="?android:attr/textColorSecondary"/>

                        <TextView
                            android:id="@+id/to"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:maxLines="2"
                            android:ellipsize="end"
                            android:textSize="10sp"
                            android:textColor="?android:attr/textColorSecondary"
                            android:textAppearance="?android:attr/textAppearanceSmall"/>

                    </LinearLayout>

                    <!-- CC -->
                    <LinearLayout
                        android:id="@+id/cc_container"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:baselineAligned="true">

                        <TextView
                            android:id="@+id/cc_label"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:paddingRight="4dip"
                            android:text="@string/message_view_cc_label"
                            android:textSize="10sp"
                            android:textStyle="bold"
                            android:textColor="?android:attr/textColorSecondary"/>

                        <TextView
                            android:id="@+id/cc"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:maxLines="2"
                            android:ellipsize="end"
                            android:textSize="10sp"
                            android:textColor="?android:attr/textColorSecondary"
                            android:textAppearance="?android:attr/textAppearanceSmall"/>

                    </LinearLayout>

                </LinearLayout>


                <!-- Date/Time + Icons -->
                <LinearLayout
                    android:id="@+id/topright_container"
                    android:layout_marginTop="2dip"
                    android:layout_marginRight="6dip"
                    android:orientation="vertical"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="6dp"
                    android:gravity="right">

                    <LinearLayout
                        android:id="@+id/icons_container"
                        android:orientation="horizontal"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:gravity="center_vertical">

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

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

                    </LinearLayout>

                    <TextView
                        android:id="@+id/date"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:singleLine="true"
                        android:ellipsize="none"
                        android:textSize="10sp"
                        android:textColor="?android:attr/textColorPrimary"
                        android:textAppearance="?android:attr/textAppearanceSmall"/>

                    <TextView
                        android:id="@+id/time"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:textSize="10sp"
                        android:singleLine="true"
                        android:ellipsize="none"
                        android:textColor="?android:attr/textColorPrimary"
                        android:textAppearance="?android:attr/textAppearanceSmall"/>

                </LinearLayout>

            </TableRow>

            <TableRow
                android:id="@+id/additional_headers_row">

                <!-- Color chip 2 -->
                <View
                    android:id="@+id/chip2"
                    android:layout_marginRight="6dip"
                    android:layout_width="6dip"
                    android:layout_height="fill_parent"/>

                <!-- Additional headers -->
                <TextView
                    android:layout_span="2"
                    android:id="@+id/additional_headers_view"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginRight="10dp"
                    android:singleLine="false"
                    android:ellipsize="none"
                    android:textSize="10sp"
                    android:textColor="?android:attr/textColorSecondary"
                    android:textAppearance="?android:attr/textAppearanceSmall" />

            </TableRow>

        </TableLayout>

        <!-- Separator -->
        <!-- This layout has an explicit height because otherwise there will be strange
             display issues when the additional headers are shown. -->
        <LinearLayout
            android:id="@+id/show_additional_headers_area"
            android:orientation="vertical"
            android:layout_width="fill_parent"
            android:layout_height="21.5dp"
            android:focusable="true"
            android:clickable="true"
            android:background="@drawable/message_view_header_background">

            <RelativeLayout
                android:orientation="horizontal"
                android:layout_width="fill_parent"
                android:layout_height="20dp">

                <!-- Color chip 3 -->
                <View
                    android:id="@+id/chip3"
                    android:layout_marginRight="6dip"
                    android:layout_width="6dip"
                    android:layout_height="fill_parent"
                    android:layout_alignParentLeft="true"/>

                <!-- Show more/less indicator -->
                <ImageView
                    android:id="@+id/show_additional_headers_icon"
                    android:src="@drawable/show_more"
                    android:layout_alignParentRight="true"
                    android:layout_alignParentBottom="true"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginBottom="4dp"
                    android:layout_marginRight="12dp"/>

            </RelativeLayout>

            <View
                android:id="@+id/separator"
                android:layout_width="fill_parent"
                android:layout_height="1.5dp"
                android:background="#59000000"/>

        </LinearLayout>

        <!-- 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>