ios - 如何实现 iOS 的 Facebook 原生登录？

Question

为我的应用程序支持 Facebook 登录的最佳做法是什么？

我正在查看现有的与 Facebook 集成的应用程序。以 Pinterest 为例，即使设备上没有安装 Facebook 应用程序，该应用程序也使用 iOS 原生登录。我也想实现这样的逻辑流程。

看着:

Get if my app is authorized to use facebook [iOS 6, FB SDK 3.2]

https://developers.facebook.com/docs/ios/

https://developer.apple.com/documentation/social/slcomposeviewcontroller

https://developer.apple.com/documentation/accounts

我不清楚如何实现回退流程，应用会执行以下操作:

如果可以使用设备登录，请使用它。如果不是，则回退到 Facebook 应用程序登录，如果不是回退到 Facebook Safari 登录。

Answer 1

您可以在打开 session 时执行此身份验证，如下所示。此枚举 FBSessionLoginBehaviorUseSystemAccountIfPresent 将执行如下步骤

1. 尝试在设置应用程序中访问 Facebook 帐户
2. 如果失败 #1，如果安装了 Facebook 原生应用，则转向快速应用切换

3. 如果 #2 失败，它将切换到 safari。

   [FBSession.activeSession openWithBehavior:FBSessionLoginBehaviorUseSystemAccountIfPresent
completionHandler:^(FBSession *session,
FBSessionState状态，
NSError *错误){
//你的代码。
}];

枚举常量清楚地说明了登录流程，我们可以随意选择其中的任何一个。

@discussion Facebook Login authorizes the application to act on behalf of the user, using the user's Facebook account. Usually a Facebook Login will rely on an account maintained outside of the application, by the native Facebook application, the browser, or perhaps the device itself. This avoids the need for a user to enter their username and password directly, and provides the most secure and lowest friction way for a user to authorize the application to interact with Facebook. If a Facebook Login is not possible, a fallback Facebook Login may be attempted, where the user is prompted to enter their credentials in a web-view hosted directly by the application.

The FBSessionLoginBehavior enum specifies whether to allow fallback, disallow fallback, or force fallback login behavior. Most applications will use the default, which attempts a normal Facebook Login, and only falls back if needed. In rare cases, it may be preferable to disallow fallback Facebook Login completely, or to force a fallback login. */

typedef enum {
    /*! Attempt Facebook Login, ask user for credentials if necessary */
    FBSessionLoginBehaviorWithFallbackToWebView      = 0,
    /*! Attempt Facebook Login, no direct request for credentials will be made */
    FBSessionLoginBehaviorWithNoFallbackToWebView    = 1,
    /*! Only attempt WebView Login; ask user for credentials */
    FBSessionLoginBehaviorForcingWebView             = 2,
    /*! Attempt Facebook Login, prefering system account and falling back to fast app switch if necessary */
    FBSessionLoginBehaviorUseSystemAccountIfPresent  = 3,
} FBSessionLoginBehavior;

注意:查看文档以了解如何使用 FB 应用程序进行应用程序切换。那么只有这个枚举会按预期工作。