Quelle  header_group_detail.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:id="@+id/group_details_container"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <ImageView
            android:id="@+id/change_group_desc_btn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:clickable="true"
            android:contentDescription="@string/edit"
            android:focusable="true"
            android:padding="10dp"
            android:scaleType="fitCenter"
            app:layout_anchor="@id/group_desc_text"
            app:layout_anchorGravity="top|right"
            app:layout_constraintBottom_toBottomOf="@+id/group_desc_text"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintHorizontal_bias="1.0"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:srcCompat="@drawable/ic_pencil_outline"
            app:tint="?attr/colorPrimary" />

        <ch.threema.app.ui.SectionHeaderView
            android:id="@+id/group_desc_title"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="16dp"
            android:text="@string/group_description"
            app:layout_constraintBottom_toTopOf="@+id/group_desc_text"
            app:layout_constraintTop_toTopOf="parent" />

        <ch.threema.app.emojis.EmojiConversationTextView
            android:id="@+id/group_desc_text"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginBottom="32dp"
            android:clickable="true"
            android:ellipsize="end"
            android:ems="10"
            android:focusable="true"
            android:linksClickable="true"
            android:maxLines="3"
            android:singleLine="false"
            android:text=""
            android:textColor="?attr/colorOnBackground"
            android:textSize="14sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toStartOf="@+id/change_group_desc_btn"
            app:layout_constraintHorizontal_chainStyle="packed"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_goneMarginRight="2dp" />

        <TextView
            android:id="@+id/expand_group_desc_text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:clickable="true"
            android:focusable="true"
            android:gravity="center"
            android:text="@string/read_more"
            android:textColor="@color/material_green"
            android:textSize="16sp"
            android:textStyle="normal|bold"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/group_desc_text"
            app:layout_constraintVertical_bias="0.0" />

        <ch.threema.app.ui.SectionHeaderView
            android:id="@+id/group_desc_changed_date"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="12dp"
            android:layout_marginBottom="16dp"
            android:text="@string/changed_group_desc_date"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/expand_group_desc_text"
            app:layout_constraintVertical_bias="0.255"
            tools:layout_editor_absoluteX="0dp" />
    </androidx.constraintlayout.widget.ConstraintLayout>

    <com.google.android.material.card.MaterialCardView
        android:id="@+id/group_notice_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="2dp"
        android:layout_marginRight="2dp"
        android:layout_marginTop="4dp"
        android:layout_marginBottom="4dp"
        android:clickable="false"
        android:orientation="vertical"
        android:visibility="visible"
        app:cardBackgroundColor="?android:attr/colorBackground"
        app:cardCornerRadius="@dimen/cardview_border_radius"
        app:cardElevation="@dimen/notice_views_elevation"
        app:strokeWidth="0dp"
        app:contentPaddingLeft="8dp"
        app:contentPaddingRight="8dp"
        app:contentPaddingTop="4dp"
        app:contentPaddingBottom="4dp"
        android:outlineProvider="none">

        <RelativeLayout
            android:id="@+id/group_notice_layout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:clickable="false">

            <TextView
                style="@style/Threema.TextAppearance.BodyMedium"
                android:id="@+id/group_notice"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginRight="8dp"
                android:layout_alignParentLeft="true"
                android:layout_centerVertical="true"
                android:textColor="?attr/colorOnBackground"
                android:ellipsize="end"
                android:maxLines="6" />

        </RelativeLayout>

    </com.google.android.material.card.MaterialCardView>

    <ch.threema.app.ui.SectionHeaderView
        android:id="@+id/group_members_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="6dp"
        android:layout_marginBottom="8dp" />

    <RelativeLayout
        android:id="@+id/add_member"
        android:layout_width="match_parent"
        android:layout_height="@dimen/group_detail_list_item_size"
        android:background="?attr/selectableItemBackground"
        android:clickable="true"
        android:contentDescription="@string/add_group_members"
        android:focusable="true"
        android:orientation="vertical">

        <ImageView
            android:id="@+id/add_member_button"
            android:layout_width="@dimen/avatar_size_small"
            android:layout_height="@dimen/avatar_size_small"
            android:layout_centerVertical="true"
            android:clickable="false"
            android:focusable="false"
            android:importantForAccessibility="no"
            android:padding="6dp"
            android:visibility="visible"
            app:srcCompat="@drawable/ic_person_add_outline"
            app:tint="?attr/colorOnSurface" />

        <TextView
            android:id="@+id/add_member_text"
            style="@style/Threema.TextAppearance.List.FirstLine"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignWithParentIfMissing="true"
            android:layout_centerVertical="true"
            android:layout_marginLeft="16dp"
            android:layout_toRightOf="@id/add_member_button"
            android:clickable="false"
            android:ellipsize="end"
            android:focusable="false"
            android:importantForAccessibility="no"
            android:singleLine="true"
            android:text="@string/add_group_members" />

    </RelativeLayout>

</LinearLayout>