How can I put the Recyclerview at the Center of the screen in Android?

I have a recycler view that displays all the saved cards but my only issue is , it never comes at the middle of the screen but to the right of the screen. I even tried marginleft but still the problem persists. Below is my code XML code of the both layout files present in it .

fragment_to_learn.xml

<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="match_parent">

    <androidx.appcompat.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:background="@drawable/flash_tablebar"
        android:elevation="4dp"
        android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
        android:layout_alignParentTop="true"
        tools:ignore="MissingConstraints">

        <ImageView
            android:id="@+id/back_icon"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            android:src="@drawable/ic_arrow_back" />
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
        </LinearLayout>
    </androidx.appcompat.widget.Toolbar>

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerview"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginTop="20dp"
        android:layout_marginLeft="20dp"
        tools:listitem="@layout/recycle_view"
        app:layout_constraintTop_toBottomOf="@id/toolbar"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5" />

</androidx.constraintlayout.widget.ConstraintLayout>

recycle_view.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_margin="20dp"
    android:layout_marginTop="40dp"
    android:background="@drawable/rounded_cardview"
    android:layout_width="match_parent"
    android:layout_height="400dp">

    <TextView
        android:layout_gravity="center"
        android:id="@+id/textView"
        style="@style/word_title"
        android:textColor="#FFFF"
        android:textStyle="bold"
        android:layout_marginStart="30dp"
        android:text="@string/word1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1" />

    <TextView
        android:layout_marginLeft="20dp"
        android:layout_gravity="center"
        android:text="@string/word2"
        android:textColor="#FFFF"
        android:textStyle="bold"
        android:id="@+id/text1"
        style="@style/word_title"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"/>

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/imageDelete"
        android:src="@drawable/baseline_delete_24"
        android:layout_gravity="center"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="20dp" />
</LinearLayout>

This is how my screen looks like instead of having the recyclerview at the center.

Remove this line android:layout_marginLeft="20dp" from below code.

<androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerview"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginTop="20dp"
        android:layout_marginLeft="20dp" // Remove this line
        tools:listitem="@layout/recycle_view"
        app:layout_constraintTop_toBottomOf="@id/toolbar"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5" />

To position the RecyclerView in the center of the screen, put it in a nested LinearLayout like below:

<LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:paddingBottom="2dp">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:orientation="horizontal">

                <LinearLayout
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:orientation="horizontal"
                    android:gravity="center">

                    <androidx.recyclerview.widget.RecyclerView
                        android:id="@+id/recyclerview"
                        android:layout_width="wrap_content"  
                        android:layout_height="wrap_content"
                        tools:listitem="@layout/recycle_view" />

                </LinearLayout>

            </LinearLayout>

        </LinearLayout>

Put the LinearLayout inside your ConstraintLayout along with all the other elements.

Modified fragment_to_learn.xml file:

<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="match_parent">

    <androidx.appcompat.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:background="@drawable/flash_tablebar"
        android:elevation="4dp"
        android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
        android:layout_alignParentTop="true"
        tools:ignore="MissingConstraints">

        <ImageView
            android:id="@+id/back_icon"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            android:src="@drawable/ic_arrow_back" />
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
        </LinearLayout>
    </androidx.appcompat.widget.Toolbar>

    <!--Add nested linear layout--> 
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal"
        android:paddingBottom="2dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:gravity="center"
                android:orientation="horizontal">
                
                <!--Change from 0dp to wrap_content-->
                <androidx.recyclerview.widget.RecyclerView
                    android:id="@+id/recyclerview"
                    android:layout_width="wrap_content"  
                    android:layout_height="wrap_content"
                    tools:listitem="@layout/recycle_view" />

            </LinearLayout>

        </LinearLayout>

    </LinearLayout>
    
</androidx.constraintlayout.widget.ConstraintLayout>

You also need to change the android:layout_width and android:layout_height from 0dp to wrap_content.