作为一种广告单元，智能横幅可在任何屏幕尺寸、任何屏幕方向的各种设备上展示与屏幕等宽的横幅广告。智能横幅广告可以检测设备处于当前屏幕方向时的宽度，并据此创建与之等宽的广告视图。
在 iPhone 上，当屏幕为纵向时，智能横幅广告高度为 50 点；当屏幕为横向时，广告高度为 32 点。在 iPad 上，智能横幅广告高度在屏幕为纵向和横向时均为 90 点。
当图片广告不足以占据所分配的整个空间时，系统会居中放置图片，然后填充两侧剩余的空间。
要使用智能横幅广告，只需为广告尺寸指定 kGADAdSizeSmartBannerPortrait（适用于纵向屏幕）或 kGADAdSizeSmartBannerLandscape（适用于横向屏幕）即可：
Swift
let bannerView = GADBannerView(adSize: kGADAdSizeSmartBannerPortrait)
Objective-C
GADBannerView *bannerView = [[GADBannerView alloc] initWithAdSize:kGADAdSizeSmartBannerPortrait];
由于 iOS 11 增加了安全区域，因此对于全宽横幅广告，您还应添加对其边缘的限制，使之不超过安全区域的边缘。以下代码段展示了如何执行此操作：
Swift
func addBannerViewToView(_ bannerView: GADBannerView) { bannerView.translatesAutoresizingMaskIntoConstraints = false view.addSubview(bannerView) if #available(iOS 11.0, *) { // In iOS 11, we need to constrain the view to the safe area. positionBannerViewFullWidthAtBottomOfSafeArea(bannerView) } else { // In lower iOS versions, safe area is not available so we use // bottom layout guide and view edges. positionBannerViewFullWidthAtBottomOfView(bannerView) } } // MARK: - view positioning @available (iOS 11, *) func positionBannerViewFullWidthAtBottomOfSafeArea(_ bannerView: UIView) { // Position the banner. Stick it to the bottom of the Safe Area. // Make it constrained to the edges of the safe area. let guide = view.safeAreaLayoutGuide NSLayoutConstraint.activate([ guide.leftAnchor.constraint(equalTo: bannerView.leftAnchor), guide.rightAnchor.constraint(equalTo: bannerView.rightAnchor), guide.bottomAnchor.constraint(equalTo: bannerView.bottomAnchor) ]) } func positionBannerViewFullWidthAtBottomOfView(_ bannerView: UIView) { view.addConstraint(NSLayoutConstraint(item: bannerView, attribute: .leading, relatedBy: .equal, toItem: view, attribute: .leading, multiplier: 1, constant: 0)) view.addConstraint(NSLayoutConstraint(item: bannerView, attribute: .trailing, relatedBy: .equal, toItem: view, attribute: .trailing, multiplier: 1, constant: 0)) view.addConstraint(NSLayoutConstraint(item: bannerView, attribute: .bottom, relatedBy: .equal, toItem: bottomLayoutGuide, attribute: .top, multiplier: 1, constant: 0)) }
Objective-C
- (void)addBannerViewToView:(UIView *)bannerView { bannerView.translatesAutoresizingMaskIntoConstraints = NO; [self.view addSubview:bannerView]; if (@available(ios 11.0, *)) { // In iOS 11, we need to constrain the view to the safe area. [self positionBannerViewFullWidthAtBottomOfSafeArea:bannerView]; } else { // In lower iOS versions, safe area is not available so we use // bottom layout guide and view edges. [self positionBannerViewFullWidthAtBottomOfView:bannerView]; } } #pragma mark - view positioning - (void)positionBannerViewFullWidthAtBottomOfSafeArea:(UIView *_Nonnull)bannerView NS_AVAILABLE_IOS(11.0) { // Position the banner. Stick it to the bottom of the Safe Area. // Make it constrained to the edges of the safe area. UILayoutGuide *guide = self.view.safeAreaLayoutGuide; [NSLayoutConstraint activateConstraints:@[ [guide.leftAnchor constraintEqualToAnchor:bannerView.leftAnchor], [guide.rightAnchor constraintEqualToAnchor:bannerView.rightAnchor], [guide.bottomAnchor constraintEqualToAnchor:bannerView.bottomAnchor] ]]; } - (void)positionBannerViewFullWidthAtBottomOfView:(UIView *_Nonnull)bannerView { [self.view addConstraint:[NSLayoutConstraint constraintWithItem:bannerView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeading multiplier:1 constant:0]]; [self.view addConstraint:[NSLayoutConstraint constraintWithItem:bannerView attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTrailing multiplier:1 constant:0]]; [self.view addConstraint:[NSLayoutConstraint constraintWithItem:bannerView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self.bottomLayoutGuide attribute:NSLayoutAttributeTop multiplier:1 constant:0]]; }