Android AdMob banner loader

Screen.java

    public void onCreate(Bundle savedInstanceState) {
        //....
        loadBanner();
        showBanner();
        //....
    }
    
    public void loadBanner() {
    	//banner ad
    	if (BANNER_AD_UNIT_ID.length() > 0) {
    	    // Create an ad.
    	    adView = new AdView(this);
            adView.setAdSize(AdSize.SMART_BANNER);
            adView.setAdUnitId(BANNER_AD_UNIT_ID);

            //make ad visible on bottom of screen
            RelativeLayout.LayoutParams params1 = new RelativeLayout.LayoutParams(
                LayoutParams.WRAP_CONTENT,
                LayoutParams.WRAP_CONTENT
            );
            params1.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
            params1.addRule(RelativeLayout.CENTER_HORIZONTAL);
            adView.setLayoutParams(params1);

            layout.addView(adView);
		}
	}

    public void showBanner() {
        adView.loadAd(new AdRequest.Builder().build());
        adView.setAdListener(new AdListener() {
            @Override
            public void onAdLoaded() {
                loadBanner();
            }
        });
    }