如何让android视图占据剩余空间

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:weightSum="1">

    <View
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="0.2"
        android:background="#FF0000" />

    <View
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="0.8"
        android:background="#00FF00" />

</LinearLayout>

<androidx.constraintlayout.widget.ConstraintLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <View
        android:id="@+id/view1"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintHeight_default="percent"
        app:layout_constraintHeight_percent="0.2"
        android:background="#FF0000" />

    <View
        android:id="@+id/view2"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintHeight_default="percent"
        app:layout_constraintHeight_percent="0.8"
        android:background="#00FF00" />

</androidx.constraintlayout.widget.ConstraintLayout>