Xamarin集成Google用户认证流程疑问：是否需通过浏览器标签页？

Great question! Let me break this down clearly so you understand why you're seeing different login behaviors and whether the tutorial's approach is valid.

Is the browser-based flow from the tutorial a legitimate Google auth process? #

Absolutely. The flow described—opening a system browser tab to handle login—is a compliant OAuth 2.0 authorization code flow, which is actually recommended by Google and most major OAuth providers. Here’s why it’s a standard approach:

• It uses the system’s existing browser session, so users might already be logged into Google without needing to re-enter credentials.
• It avoids storing sensitive authentication data directly in your app, reducing security risks like credential theft or phishing vulnerabilities.
• It’s a universal implementation that works with nearly any OAuth provider (not just Google), which is why the Xamarin guide uses it as a generalizable example.

Why do other apps skip opening a browser? #

Those apps are using alternative approaches to deliver a more native-feeling experience:

• Google Sign-In SDK for Xamarin: This official SDK integrates with platform-specific services (Google Play Services on Android, Google’s native Sign-In framework on iOS). Instead of launching a browser, it triggers a system-level login dialog that feels seamless within the app.
• Embedded WebView: Some apps load Google’s login page inside an in-app WebView instead of using the system browser. While this keeps users within the app, it’s less secure (WebViews can be vulnerable to injection attacks) and doesn’t leverage existing system login sessions.

Which approach should you choose? #

• Stick with the tutorial’s browser-based flow if you want a secure, provider-agnostic implementation that follows OAuth best practices.
• Switch to the Google Sign-In SDK if you prioritize a native, app-integrated login experience. It’s tailored specifically for Google accounts and includes features like one-tap sign-in.

内容的提问来源于stack exchange，提问作者Dre