ImageView Ratio XML

gistfile1.txt

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:scaleType="centerCrop"
        android:src="@drawable/ic_launcher_background"
        app:layout_constraintHeight_percent="0.4"
        app:layout_constraintTop_toTopOf="parent" />
    
</androidx.constraintlayout.widget.ConstraintLayout>