FairEmail/app/src/main/res/layout/activity_eml.xml

<eu.faircode.email.ConstraintLayoutEx xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="eu.faircode.email.ActivityEML">

    <eu.faircode.email.ScrollViewEx
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:paddingHorizontal="6dp"
        android:paddingVertical="12dp"
        android:scrollbarStyle="outsideOverlay"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <eu.faircode.email.ConstraintLayoutEx
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <eu.faircode.email.FixedTextView
                android:id="@+id/tvHint"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_marginTop="3dp"
                android:drawableStart="@drawable/twotone_info_24"
                android:drawablePadding="6dp"
                android:text="@string/title_hint_eml"
                android:textAppearance="@style/TextAppearance.AppCompat.Small"
                android:textStyle="italic"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent" />

            <androidx.cardview.widget.CardView
                android:id="@+id/cardMessage"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginHorizontal="3dp"
                android:layout_marginTop="12dp"
                app:cardBackgroundColor="?attr/colorCardBackground"
                app:cardCornerRadius="6dp"
                app:cardElevation="0dp"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@id/tvHint">

                <eu.faircode.email.ConstraintLayoutEx
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:paddingHorizontal="6dp"
                    android:paddingVertical="12dp">

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvFromTitle"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="@string/title_from"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textStyle="bold"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toTopOf="parent" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvFrom"
                        android:layout_width="0dp"
                        android:layout_height="wrap_content"
                        android:layout_marginStart="6dp"
                        android:text="From"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textIsSelectable="true"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toEndOf="@id/tvFromTitle"
                        app:layout_constraintTop_toTopOf="parent" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvToTitle"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="@string/title_to"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textStyle="bold"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toBottomOf="@id/tvFrom" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvTo"
                        android:layout_width="0dp"
                        android:layout_height="wrap_content"
                        android:layout_marginStart="6dp"
                        android:text="To"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textIsSelectable="true"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toEndOf="@id/tvToTitle"
                        app:layout_constraintTop_toBottomOf="@id/tvFrom" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvReplyToTitle"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="@string/title_reply_to"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textStyle="bold"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toBottomOf="@id/tvTo" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvReplyTo"
                        android:layout_width="0dp"
                        android:layout_height="wrap_content"
                        android:layout_marginStart="6dp"
                        android:text="Reply to"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textIsSelectable="true"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toEndOf="@id/tvReplyToTitle"
                        app:layout_constraintTop_toBottomOf="@id/tvTo" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvCcTitle"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="@string/title_cc"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textStyle="bold"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toBottomOf="@id/tvReplyTo" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvCc"
                        android:layout_width="0dp"
                        android:layout_height="wrap_content"
                        android:layout_marginStart="6dp"
                        android:text="CC"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textIsSelectable="true"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toEndOf="@id/tvCcTitle"
                        app:layout_constraintTop_toBottomOf="@id/tvReplyTo" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvBccTitle"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="@string/title_bcc"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textStyle="bold"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toBottomOf="@id/tvCc" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvBcc"
                        android:layout_width="0dp"
                        android:layout_height="wrap_content"
                        android:layout_marginStart="6dp"
                        android:text="BCC"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textIsSelectable="true"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toEndOf="@id/tvBccTitle"
                        app:layout_constraintTop_toBottomOf="@id/tvCc" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvSentTitle"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="@string/title_sent"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textStyle="bold"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toBottomOf="@id/tvBcc" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvSent"
                        android:layout_width="0dp"
                        android:layout_height="wrap_content"
                        android:layout_marginStart="6dp"
                        android:text="Sent"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textIsSelectable="true"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toEndOf="@id/tvSentTitle"
                        app:layout_constraintTop_toBottomOf="@id/tvBcc" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvReceivedTitle"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="@string/title_received"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textStyle="bold"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toBottomOf="@id/tvSent" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvReceived"
                        android:layout_width="0dp"
                        android:layout_height="wrap_content"
                        android:layout_marginStart="6dp"
                        android:text="Received"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textIsSelectable="true"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toEndOf="@id/tvReceivedTitle"
                        app:layout_constraintTop_toBottomOf="@id/tvSent" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvSubject"
                        android:layout_width="0dp"
                        android:layout_height="wrap_content"
                        android:text="Subject"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textIsSelectable="true"
                        android:textStyle="italic"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toBottomOf="@id/tvReceived" />

                    <View
                        android:id="@+id/vSeparatorAttachments"
                        android:layout_width="0dp"
                        android:layout_height="1dp"
                        android:layout_marginTop="3dp"
                        android:background="?attr/colorSeparator"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toBottomOf="@id/tvSubject" />

                    <androidx.recyclerview.widget.RecyclerView
                        android:id="@+id/rvAttachment"
                        android:layout_width="0dp"
                        android:layout_height="wrap_content"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toBottomOf="@+id/vSeparatorAttachments" />

                    <View
                        android:id="@+id/vSeparatorBody"
                        android:layout_width="0dp"
                        android:layout_height="1dp"
                        android:layout_marginTop="3dp"
                        android:background="?attr/colorSeparator"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toBottomOf="@id/rvAttachment" />

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvBody"
                        android:layout_width="0dp"
                        android:layout_height="wrap_content"
                        android:layout_marginTop="3dp"
                        android:text="Body"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textIsSelectable="true"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toBottomOf="@id/vSeparatorBody" />

                </eu.faircode.email.ConstraintLayoutEx>
            </androidx.cardview.widget.CardView>

            <androidx.cardview.widget.CardView
                android:id="@+id/cardStructure"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginHorizontal="3dp"
                android:layout_marginTop="12dp"
                app:cardBackgroundColor="?attr/colorCardBackground"
                app:cardCornerRadius="6dp"
                app:cardElevation="0dp"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@id/cardMessage">

                <eu.faircode.email.ConstraintLayoutEx
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:paddingHorizontal="6dp"
                    android:paddingVertical="12dp">

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvStructure"
                        android:layout_width="0dp"
                        android:layout_height="wrap_content"
                        android:layout_marginTop="3dp"
                        android:fontFamily="monospace"
                        android:minHeight="30dp"
                        android:text="Structure"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textIsSelectable="true"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toTopOf="parent" />

                    <eu.faircode.email.FixedImageButton
                        android:id="@+id/ibEml"
                        android:layout_width="36dp"
                        android:layout_height="36dp"
                        android:layout_marginEnd="6dp"
                        android:background="?attr/selectableItemBackground"
                        android:padding="3dp"
                        app:layout_constraintBottom_toBottomOf="@id/tvStructure"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:srcCompat="@drawable/baseline_code_24" />
                </eu.faircode.email.ConstraintLayoutEx>
            </androidx.cardview.widget.CardView>

            <androidx.cardview.widget.CardView
                android:id="@+id/cardHeaders"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginHorizontal="3dp"
                android:layout_marginTop="12dp"
                app:cardBackgroundColor="?attr/colorCardBackground"
                app:cardCornerRadius="6dp"
                app:cardElevation="0dp"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@id/cardStructure">

                <eu.faircode.email.ConstraintLayoutEx
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:paddingHorizontal="6dp"
                    android:paddingVertical="12dp">

                    <eu.faircode.email.FixedTextView
                        android:id="@+id/tvHeaders"
                        android:layout_width="0dp"
                        android:layout_height="wrap_content"
                        android:layout_marginTop="3dp"
                        android:fontFamily="monospace"
                        android:minHeight="30dp"
                        android:text="Headers"
                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
                        android:textIsSelectable="true"
                        app:layout_constraintEnd_toEndOf="parent"
                        app:layout_constraintStart_toStartOf="parent"
                        app:layout_constraintTop_toTopOf="parent" />
                </eu.faircode.email.ConstraintLayoutEx>
            </androidx.cardview.widget.CardView>

            <androidx.constraintlayout.widget.Group
                android:id="@+id/grpReady"
                android:layout_width="0dp"
                android:layout_height="0dp"
                app:constraint_referenced_ids="cardMessage,cardStructure" />
        </eu.faircode.email.ConstraintLayoutEx>
    </eu.faircode.email.ScrollViewEx>

    <eu.faircode.email.ContentLoadingProgressBar
        android:id="@+id/pbWait"
        style="@style/Base.Widget.AppCompat.ProgressBar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:indeterminate="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</eu.faircode.email.ConstraintLayoutEx>