这是一个围绕Google网络身份验证的轻量级包装，适用于移动设备。
let viewController = DANGoogleSignInViewController(clientId: "your google client id", scopes: ["your google scopes"])
navigationController.pushViewController(viewController, animated: true)或在遗留项目中
DANGoogleSignInViewController *viewController = [[DANGoogleSignInViewController alloc] initWithClientId:@"your google client id" scopes:@[@"your google scopes"]];
[self.navigationController pushViewController:viewController animated:YES];CocoaPods是推荐的安装方法。
pod 'DANGoogleSignIn'