How to implement AdMob collapsible Banner ads in android

implementation 'com.google.android.gms:play-services-ads:23.3.0'

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    

<meta-data 
    android:name="com.google.android.gms.ads.APPLICATION_ID" 
    android:value="ca-app-pub-3940256099942544~3347511713" />
    

<FrameLayout
    android:id="@+id/adContainer"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginBottom="20dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"  />
    

private static final String AD_UNIT_ID = "ca-app-pub-3940256099942544/2014213617";
private AdView adView;
    

MobileAds.initialize(this, initializationStatus -> {}); 
loadBannerAd();
    

private void loadBannerAd() {
    FrameLayout adContainer = findViewById(R.id.adContainer);
    adView = new AdView(this);
    adView.setAdUnitId(AD_UNIT_ID);
    adView.setAdSize(getAdSize());
    adContainer.addView(adView);

    Bundle extras = new Bundle();
    extras.putString("collapsible", "bottom");

    AdRequest adRequest = new AdRequest.Builder()
            .addNetworkExtrasBundle(AdMobAdapter.class, extras)
            .build();

    adView.loadAd(adRequest);
}

private AdSize getAdSize() {
    DisplayMetrics displayMetrics = getResources().getDisplayMetrics();
    int adWidthPixels = Build.VERSION.SDK_INT >= Build.VERSION_CODES.R
            ? getWindowManager().getCurrentWindowMetrics().getBounds().width()
            : displayMetrics.widthPixels;

    return AdSize.getCurrentOrientationAnchoredAdaptiveBannerAdSize(this, (int) (adWidthPixels / displayMetrics.density));
}