智能横幅广告

改为试用新型自适应横幅广告。

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。

如需使用智能横幅广告，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]];
}