Constraint layout with top title, recycler view and bottom button

Question

I am trying to implement a layout, which will contain the top title, recycler view and bottom button. Looks simple, but I need to have a wrap_content height for constraint layout to make it scalable depending on the content (top title, bottom button and recycler view. All examples that I've already found with match_parent value. Also, I need to keep the title and bottom button on the screen, where there are a lot of recycler view items. In turn recycler view must fill all available place and don't overlap title and bottom button.

So, requirements for layout:

1. Title is always on the screen
2. Bottom button is always on the screen
3. Constraint layout must be scalable depending on the recycler view content (picture below)

The concept:

Layout which I have now

 <?xml version="1.0" encoding="utf-8"?>
   <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="wrap_content">

    <TextView
        android:id="@+id/tvTitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Title"
        android:background="@color/yellow"
        android:textAlignment="center"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:textSize="16dp"
        android:textStyle="bold" />

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rvList"
        android:layout_width="wrap_content"
        android:layout_height="@dimen/constraint_parent"
        app:layout_constraintBottom_toTopOf="@id/btnSave"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/tvTitle"
        tools:itemCount="50" />

    <androidx.appcompat.widget.AppCompatButton
        android:id="@+id/btnSave"
        android:layout_width="@dimen/constraint_parent"
        android:layout_height="wrap_content"
        android:text="Save"
        android:textSize="16dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

Result - recycler view isn't displayed

Perhaps there is another way to do this, but I spent a lot of time looking for a solution. I believe the solution should be simple, but I haven't found one yet. DialogFragment doesn't fit here because this screen needs to be in full-screen mode when the app is in portrait orientation.

Answer 1

Just constraint the bottom button (btnSave) as - app:layout_constraintTop_toBottomOf="@id/rvList"

Also don't fix the height of the recyclerView. Keep it as wrap_content

Answer 2

Try to set android:layout_height to match_parent on your ContraintLayout.