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 <style name="ShapeAppearanceOverlay.App.CornerSize50Percent" parent="">
        <item name="cornerSize">50%</item>
    </style>

<androidx.constraintlayout.widget.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"
    tools:context=".MainActivity">


   <androidx.recyclerview.widget.RecyclerView
       android:id="@+id/recview"
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       app:layout_constraintBottom_toBottomOf="parent"
       app:layout_constraintEnd_toEndOf="parent"
       app:layout_constraintHorizontal_bias="0.0"
       app:layout_constraintStart_toStartOf="parent"
       app:layout_constraintTop_toTopOf="parent"
       app:layout_constraintVertical_bias="0.0" />

   <com.google.android.material.floatingactionbutton.FloatingActionButton
       android:id="@+id/fadd"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:clickable="true"
       app:backgroundTint="@color/apptheam"
       app:borderWidth="0dp"
       app:elevation="6dp"
       app:fabSize="normal"
       app:layout_constraintBottom_toBottomOf="parent"
       app:layout_constraintEnd_toEndOf="parent"
       app:layout_constraintHorizontal_bias="0.884"
       app:layout_constraintStart_toStartOf="parent"
       app:layout_constraintTop_toTopOf="parent"
       app:layout_constraintVertical_bias="0.945"
       app:srcCompat="@drawable/ic_baseline_add_24" />


</androidx.constraintlayout.widget.ConstraintLayout>