Show AdMob

// Initialize the banner at the bottom of the screen.

    CGPoint origin = CGPointMake(0.0,

                                 self.view.frame.size.height -

                                 CGSizeFromGADAdSize(kGADAdSizeBanner).height);

// Use predefined GADAdSize constants to define the GADBannerView.

    bannerView_ = [[GADBannerView alloc] initWithAdSize:kGADAdSizeBanner

                                                    origin:origin]

                     ;

// Note: Provide a definition for ADMOB_ID

    // before compiling.

    bannerView_.adUnitID = ADMOB_ID;

    [bannerView_ setRootViewController:self];

    [self.view addSubview:bannerView_];

    [bannerView_ loadRequest:[GADRequest request]];