notebook_sheet.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
    android:background="#66330E">

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="vertical"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_margin="8dp">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="8dp"
            android:background="@drawable/sheet_background"
            android:orientation="vertical">

            <fragment
                android:id="@+id/fragment_new_word"
                android:name="com.paktalin.vocabularynotebook.ui.NewWordFragment"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="8dp" />

            <fragment
                android:id="@+id/fragment_vocabulary"
                android:name="com.paktalin.vocabularynotebook.ui.VocabularyFragment"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
        </LinearLayout>

    </ScrollView>

    <FrameLayout
        android:id="@+id/btnAddWordLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/colorPrimary"
        android:visibility="gone"
        app:layout_constraintBottom_toBottomOf="parent">

        <ImageButton
            android:id="@+id/btnAddWord"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="end"
            android:layout_marginBottom="8dp"
            android:layout_marginEnd="8dp"
            android:layout_marginRight="8dp"
            android:background="@android:color/transparent"
            app:srcCompat="@drawable/ic_done_icon"
            tools:ignore="ContentDescription" />

    </FrameLayout>

</android.support.constraint.ConstraintLayout>