无法在我的 iOS9 应用程序中打印 FBSDKAccessToken.currentAccessToken().tokenString [英] Cannot print the FBSDKAccessToken.currentAccessToken().tokenString in my iOS9 app

问题描述

我正在 Swift 中为 iOS 9 创建一个应用程序以用于学习目的.当我通过我的应用程序登录 Facebook 时，我试图打印 Facebook 的当前访问令牌.

I was creating an app in Swift for iOS 9 for learning purposes. I was trying to print the current access Token of Facebook at time when I log into Facebook through my app.

当我单击 fblogin 按钮时，它会打开 Safari 并显示我已经授权了我的应用程序，但是当我单击确定"时，它卡在 Safari 页面上并且没有按应有的方式打印令牌.它说:

When I click the fblogin button it opens Safari and shows me that I already have authorized my app but when I click okay it stuck on the Safari page and doesn't print the token as it should. And it says :

致命错误:解包可选值时意外发现 nil

fatal error: unexpectedly found nil while unwrapping an Optional value

我使用的是 XCode 7.3.1.我正在添加代码的图片:

I am using XCode 7.3.1. I am adding the pic of the code:

推荐答案

可能是此时在完成处理程序中，FBSDKAccessToken.currentAccessToken() 尚未保存，这就是原因它仍然是 nil.您可以在 FBSDKLoginManagerLoginResult 上使用 @property (copy, nonatomic) FBSDKAccessToken *token; 属性:

It might be that at this point in the completion handler, the FBSDKAccessToken.currentAccessToken() isn't saved yet, that's why it's still nil. You can use the @property (copy, nonatomic) FBSDKAccessToken *token; property on FBSDKLoginManagerLoginResult:

FBSDKLoginManager().logInWithReadPermissions(["email"], fromViewController: self) { (facebookResult: FBSDKLoginManagerLoginResult!, facebookError: NSError!) in
  if let token = facebookResult.token.tokenString {
    print(token)
  }
}

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