Gadgetbridge/app/src/main/res/layout/activity_contact_details.xml

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/constraintLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="nodomain.freeyourgadget.gadgetbridge.activities.ContactDetails">

    <com.google.android.material.card.MaterialCardView
        android:id="@+id/card_contact_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="8dp"
        android:foreground="?android:attr/selectableItemBackground"
        app:cardBackgroundColor="?attr/cardview_background_color"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        card_view:cardElevation="3dp"
        card_view:contentPadding="4dp">

        <androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="8dp">

            <TextView
                android:id="@+id/label_contact_name"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/contact_name"
                android:textAppearance="?android:attr/textAppearance"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent" />

            <EditText
                android:id="@+id/contact_name"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="2dp"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@id/label_contact_name" />
        </androidx.constraintlayout.widget.ConstraintLayout>
    </com.google.android.material.card.MaterialCardView>

    <com.google.android.material.card.MaterialCardView
        android:id="@+id/card_contact_number"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="8dp"
        android:foreground="?android:attr/selectableItemBackground"
        app:cardBackgroundColor="?attr/cardview_background_color"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/card_contact_name"
        card_view:cardElevation="3dp"
        card_view:contentPadding="4dp">

        <androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_margin="8dp">

            <TextView
                android:id="@+id/label_contact_number"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/contact_phone_number"
                android:textAppearance="?android:attr/textAppearance"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent" />

            <EditText
                android:id="@+id/contact_number"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="2dp"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toBottomOf="@id/label_contact_number" />
        </androidx.constraintlayout.widget.ConstraintLayout>
    </com.google.android.material.card.MaterialCardView>

    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@+id/fab_save"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="16dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:srcCompat="@drawable/ic_save" />
</androidx.constraintlayout.widget.ConstraintLayout>