<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="pl.komunikator.komunikator.ConversationsListActivity"
    tools:showIn="@layout/app_bar_conversations_list">

</android.support.constraint.ConstraintLayout>

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="pl.komunikator.komunikator.ConversationsListActivity"
    tools:showIn="@layout/app_bar_conversations_list">

    <android.support.v7.widget.RecyclerView
        android:layout_width="368dp"
        android:layout_height="495dp"
        android:layout_marginRight="0dp"
        app:layout_constraintRight_toRightOf="parent"
        android:layout_marginLeft="0dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginTop="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        android:layout_marginBottom="0dp" />
</android.support.constraint.ConstraintLayout>

Add recycler view to the layout
Add recycler view to the layout
