Packed chain with gravity top

Question

I have two view that are fit at the top and bottom of the screen and I have a Recycler view that will sit between them but there is one view that much be packed with recyclview vertically. Something like this

I have to use constraint layout to achieve this. I have tried to achieve this with using packed-chain but that puts the view in center of screen not align to the the top view.

Answer 1

Change the bias of the chain to zero and that will position the RecyclerView and the view below it to the top of the center area. Something like this:

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

    <TextView
        android:id="@+id/textView2"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginEnd="16dp"
        android:text="Bottom View"
        android:textSize="24sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="16dp"
        android:gravity="center"
        android:text="Top"
        android:textSize="24sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constrainedHeight="true"
        android:layout_marginStart="16dp"
        android:layout_marginTop="16dp"
        android:layout_marginEnd="16dp"
        android:background="@android:color/holo_green_light"
        app:layout_constraintBottom_toTopOf="@+id/textView3"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView"
        app:layout_constraintVertical_bias="0.0"
        app:layout_constraintVertical_chainStyle="packed" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="View"
        android:textSize="24sp"
        app:layout_constraintBottom_toTopOf="@+id/textView2"
        app:layout_constraintStart_toStartOf="@+id/recyclerView"
        app:layout_constraintTop_toBottomOf="@+id/recyclerView" />

</androidx.constraintlayout.widget.ConstraintLayout>

I think the key point here is that the top and bottom views do not have to be part of the chain.

You could also, maybe, do the same without the chain by constraining the tops of the center views.