Android remove strange distance between bottomnavview and ad

Question

Here is how it looks like

I want to remove the distance between bottom of the ad and top of the bottom navigation view. I have no idea where is this gap comming from.

Here is my code:

MainActivity.java

private void initFragment() {
    bottomNavigationView.post(() -> {
        bottomNavViewHeight = bottomNavigationView.getMeasuredHeight();
        FragmentList fragmentOne = new FragmentList();
        Bundle args = new Bundle();
        args.putInt("b_nav_height", bottomNavViewHeight);
        fragmentOne.setArguments(args);
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        ft.replace(R.id.content_frame, fragmentOne);
        ft.commit();
    });
}

FragmentList.java

private void initAd() {
    AdView mAdView = getView().findViewById(R.id.adView);
    RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) mAdView.getLayoutParams();
    Bundle bundle = getArguments();
    if (bundle != null) {
        numberOfCols = bundle.getString("number_of_cols", "null");
        bottomNavHeight = bundle.getInt("b_nav_height", 0);
    }
    params.setMargins(0, 0, 0, bottomNavHeight); //substitute parameters for left, top, right, bottom
    mAdView.setLayoutParams(params);
    AdRequest adRequest = new AdRequest.Builder()
            .build();
    mAdView.loadAd(adRequest);
}

main_activity.xml

<?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"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <include
        layout="@layout/app_bar_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <FrameLayout
        android:id="@+id/frame_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/navigation"
        android:animateLayoutChanges="true">

        <com.google.android.material.bottomnavigation.BottomNavigationView
            android:id="@+id/bottomNavigation"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom"
            android:background="?attr/myBackgroundColor"
            app:menu="@menu/bottom_navigation_items"
            app:labelVisibilityMode="selected"
            app:itemTextAppearanceActive="@color/colorAccent"
            app:itemTextColor="@color/bottom_nav_color"
            app:itemIconTint="@color/bottom_nav_color"/>

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

fragment_list.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:ads="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

<androidx.swiperefreshlayout.widget.SwipeRefreshLayout
    android:id="@+id/swipeContainer"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_above="@id/adView">

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/card_view_recycler_list"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_above="@+id/adView" />

</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>

<com.google.android.gms.ads.AdView
    android:id="@+id/adView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    ads:adSize="BANNER"
    ads:adUnitId="ca-app-pub-3940256099942544/6300978111" />
</RelativeLayout>

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