Android ConstraintLayout Fill by Percentage

ImageView height and width is 50% of screen height and width.
<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">


    <ImageView
        android:id="@+id/imageView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintHeight_percent="0.5"
        app:layout_constraintWidth_percent="0.5"
        android:background="#FE2EF7"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>


</androidx.constraintlayout.widget.ConstraintLayout>